Unusual Ring Contration by Substitution of 4-O-activated-pentono-1,5-lactams with cyanide. Stereospecific Synthesis of 6-Amino-1,4,5,6-tetradeoxy-1,4-imino-hexitols

DEFF Research Database (Denmark)

Godskesen, Michael Anders; Lundt, Inge; Søtofte, Inger

2000-01-01

Reaction of 4-O-sulfonylated 2,3-O-isopropylidene-D-ribo- or -D-lyxo-1,5-lactams with tetrabutylammonium cyanide gave 4-amino-5-C-cyano-4,5-dideoxy-2,3-O-isopropylidene-L-lyxo-5 or -L-ribo-15-1,4-lactams, respectively. A stereospecific ring contraction with inversion at C-4 had taken place in each...

2-[4-(2-Chloroacetylphenyl]-2-methyl-1-(pyrrolidin-1-ylpropan-1-one

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Dong-mei Ren

2013-08-01

Full Text Available The asymmetric unit of the title compound, C16H20ClNO2, contains two molecules in which the dihedral angles between the benzene ring and the plane of the amide unit are 77.4 (1 and 81.1 (1°. In both molecules, the five-membered ring adopts an envelope conformation with one of the β-C atoms as the flap. In the crystal, molecules are connected via C—H...O hydrogen bonds, forming chains along the b-axis direction. These chains are further linked by C—H...π interactions, forming a three-dimensional network.

Moving ring reactor 'Karin-1'

International Nuclear Information System (INIS)

1983-12-01

The conceptual design of a moving ring reactor ''Karin-1'' has been carried out to advance fusion system design, to clarify the research and development problems, and to decide their priority. In order to attain these objectives, a D-T reactor with tritium breeding blanket is designed, a commercial reactor with net power output of 500 MWe is designed, the compatibility of plasma physics with fusion engineering is demonstrated, and some other guideline is indicated. A moving ring reactor is composed mainly of three parts. In the first formation section, a plasma ring is formed and heated up to ignition temperature. The plasma ring of compact torus is transported from the formation section through the next burning section to generate fusion power. Then the plasma ring moves into the last recovery section, and the energy and particles of the plasma ring are recovered. The outline of a moving ring reactor ''Karin-1'' is described. As a candidate material for the first wall, SiC was adopted to reduce the MHD effect and to minimize the interaction with neutrons and charged particles. The thin metal lining was applied to the SiC surface to solve the problem of the compatibility with lithium blanket. Plasma physics, the engineering aspect and the items of research and development are described. (Kako, I.)

The first C4-functionalisation of condensed tannins. Phlobatannins as prototype of a new class of C-ring isomerised oligomers

International Nuclear Information System (INIS)

Steenkamp, J.A.

1986-06-01

This thesis comprises besides the characterisation of new oligomeric flavenoids from the core wood of the indigeneous Colophosphermum mopane, an investigation into the C 4 -functionalisation of flavan-3-ol analogues. The first peltogynoid biflavenoid and prototypes of a new series C-ring isomerised condensed tannins, namely the phlobatannins, were isolated. Besides 1 H- nmr-parameters for structure analysis, the natural phlobatannins were characterised and the unique ring isomerisation was investigated

Ring-expansion synthesis and crystal structure of dimethyl 4-ethyl-1,4,5,6,7,8-hexahydroazonino[5,6-b]indole-2,3-dicarboxylate

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Van Tuyen Nguyen

2017-03-01

Full Text Available The title compound, C20H24N2O4, is the product of a ring-expansion reaction from a seven-membered hexahydroazepine to a nine-membered azonine. The azonine ring of the molecule adopts a chair–boat conformation. In the crystal, molecules are linked by bifurcated N—H...(O,O hydrogen bonds, generating [010] zigzag chains. The title compound shows inhibitory activity against acetylcholinesterase and butyrylcholinesterase, and might be considered as a candidate for the design of new types of anti-Alzheimer's drugs.

4-Fluoro-N-methyl-N-(1,2,3,4-tetrahydrocarbazol-3-ylbenzenesulfonamide

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Kaspar Gothardt Rasmussen

2009-04-01

Full Text Available In the title compound, C19H19FN2O2S, the hydrogenated six-membered ring of the carbazole unit adopts a half-chair conformation and the plane of the fluorophenyl ring forms a dihedral angle of 41.5 (1° with respect to the carbazole mean plane. The crystal structure is segregated into layers containing the carbazole units and fluorophenyl rings in alternate (200 planes. The carbazole units form centrosymmetric face-to-face interactions [interplanar separation = 4.06 (1 Å] and edge-to-face interactions in which the N—H group is directed towards an adjacent carbazole face, with a shortest H...C contact of 2.53 Å. The fluorophenyl rings form face-to-face contacts with an approximate interplanar separation of 3.75 Å and a centroid–centroid distance of 4.73 (1 Å.

Ethyl 2-(1,2,3,4-tetrahydrospiro[carbazole-3,2′-[1,3]dioxolan]-9-ylacetate

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Philipp M. G. Löffler

2009-04-01

Full Text Available In the title compound, C18H21NO4, the hydrogenated six-membered ring of the carbazole unit adopts a half-chair conformation. The dioxolane ring and ethylacetate substituent point to opposite sides of the carbazole plane. The ethylacetate substituent adopts an essentially fully extended conformation, and its mean plane forms a dihedral angle of 83.8 (1° with respect to the carbazole mean plane. The molecules are arranged into stacks in which the carbazole planes form a dihedral angle of 4.4 (1° and have an approximate interplanar separation of 3.6 Å.

2,6-Diphenyl-4-(2-thienyl-1,4-dihydropyridine-3,5-dicarbonitrile

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Xiao-Tong Zhu

2009-09-01

Full Text Available The asymmetric unit of the title compound, C23H15N3S, contains two crystallographically independent molecules. The pyridine rings adopt envelope conformations. The thiophene rings are oriented at dihedral angles of 77.97 (4/53.53 (4 and 78.44 (4/57.11 (4° with respect to the phenyl rings, while the dihedral angles between the phenyl rings are 48.51 (4 and 44.49 (4°. In the crystal structure, intermolecular N—H...N hydrogen bonds link the molecules into chains along the c axis. The S, C and H atoms of one of the thiophene rings are disordered over two orientations, with occupancy ratios of 0.314 (15:0.686 (15.

3-(4-Fluorobenzoyl-4-(4-fluorophenyl-4-hydroxy-2,6-diphenylcyclohexane-1,1-dicarbonitrile

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B. Narayana

2014-06-01

Full Text Available In the title compound, C33H24F2N2O2, the cyclohexane ring adopts a slightly distorted chair conformation. The dihedral angle between the planes of the phenyl rings is 71.80 (9°, while the planes of the fluorophenyl and fluorobenzoyl rings are inclined to one another by 31.04 (10°. The dihedral angles between the planes of the phenyl ring adjacent to the 4-hydroxy group and those of the the fluorophenyl and fluorobenzoyl rings are 51.64 (10 and 34.31 (10°, respectively, while the corresponding angles for the phenyl ring adjacent to the 3-(4-fluorobenzoyl group are 57.51 (9 and 85.02 (10°, respectively. An intramolecular O—H...O hydrogen bond generates an S(6 ring motif. In the crystal, molecules are linked via pairs of O—H...N hydrogen bonds, forming inversion dimers. The dimers are linked via C—H...N and C—H...O hydrogen bonds, forming chains along the c-axis direction. C—H...F hydrogen bonds link the chains into sheets lying parallel to the bc plane.

5-(4-Ethoxyphenyl-3-(pyridin-2-yl-4,5-dihydro-1H-pyrazole-1-carbothioamide

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Hoong-Kun Fun

2012-03-01

Full Text Available In the title compound, C17H18N4OS, a pyrazoline derivative, the pyrazoline ring adopts an envelope conformation with the C atom bonded to the benzene ring as the flap atom. The dihedral angle between the pyridine and benzene rings is 80.50 (6°. The ethoxyphenyl group is approximately planar, with an r.m.s. deviation of 0.0238 (1 Å for the nine non-H atoms. In the crystal, molecules are linked by N—H...O and N—H...S hydrogen bonds into a tape along the b axis. Weak C—H...N and C—H...π interactions are also observed.

Crystal structure of 1-[(2S*,4R*-6-fluoro-2-methyl-1,2,3,4-tetrahydroquinolin-4-yl]pyrrolidin-2-one

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P. S. Pradeep

2014-09-01

Full Text Available In the title compound, C14H17FN2O, the 1,2,3,4-tetrahydropyridine ring of the quinoline moiety adopts a half-chair conformation, while the pyrrolidine ring has an envelope conformation with the central methylene C atom as the flap. The pyrrolidine ring lies in the equatorial plane and its mean plane is normal to the mean plane of the quinoline ring system, with a dihedral angle value of 88.37 (9°. The bridging N—C bond distance [1.349 (3 Å] is substantially shorter than the sum of the covalent radii (dcov: C—N = 1.47 Å and C=N = 1.27 Å, which indicates partial double-bond character for this bond, resulting in a certain degree of charge delocalization. In the crystal, molecules are linked by N—H...O and C—H...O hydrogen bonds, forming sheets lying parallel to (10-1. These two-dimensional networks are linked via C—H...F hydrogen bonds and C—H...π interactions, forming a three-dimensional structure.

(11-Methylpyrido[2,3-b][1,4]benzodiazepin-6-yl(phenylmethanone

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Fuqiang Shi

2010-09-01

Full Text Available In the title compound, C20H15N3O, the diazepine ring adopts a boat conformation. The dihedral angle between pyridine and benzene rings is 55.2 (1°. The benzoyl phenyl ring forms dihedral angles of 49.4 (1 and 75.9 (1°, respectively, with the pyridine and benzene rings. In the crystal, molecules are linked into centrosymmetric dimers by pairs of C—H...N hydrogen bonds.

Crystal structures of three 1-oxo-1,2-dihydronaphthalene derivatives: dimethyl 4-(4-methoxyphenyl-2-(4-methylphenyl-1-oxo-1,2-dihydronaphthalene-2,3-dicarboxylate, dimethyl 1-oxo-2-(pyren-4-yl-4-(thiophen-2-yl-1,2-dihydronaphthalene-2,3-dicarboxylate and ethyl 1-oxo-2-phenyl-2,4-bis(thiophen-2-yl-1,2-dihydronaphthalene-3-carboxylate

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S. Gopinath

2017-02-01

Full Text Available In the title 1-oxo-1,2-dihydronaphthalene derivatives, C28H24O6, (I, C34H22O5S, (II, and C27H20O3S2, (III, the cyclohexa-1,3-diene rings of the 1,2-dihydronaphthalene ring systems adopt half-chair, boat and half-chair conformations, respectively. The carbonyl O atoms attached to the dihydronaphthalene ring systems are each significantly deviated from the mean plane of the 1,2-dihydronaphthalene ring system, by 0.6162 (12 Å in (I, 0.6016 (16 Å in (II and 0.515 (3 Å in (III. The mean planes of the 1,2-dihydronaphthalene ring systems make dihedral angles of 85.83 (3, 88.19 (3 and 81.67 (8°, respectively, with the methylphenyl ring in (I, the pyrene ring in (II and the phenyl ring in (III. In (I, the molecular structure is stabilized by an intramolecular C—H...O hydrogen bond, generating an S(6 ring motif. In the crystal of (I, molecules are linked by an intermolecular C—H...O hydrogen bond, which generates a C(8 zigzag chain running along [100]. Adjacent chains are further connected by C—H...π and offset π–π interactions [centroid–centroid distance = 3.6572 (9 Å], forming a double-chain structure. In the crystals of (II and (III, molecules are linked into chain structures by offset π–π interactions with centroid–centroid distances of 3.5349 (12 and 3.8845 (13 Å for (II and 3.588 (2 Å for (III. In (II and (III, the thiophene rings are orientationally disordered over two sites, with occupancy ratios of 0.69:0.31 for (II, and 0.528 (4:0.472 (4 and 0.632 (5:0.368 (5 for (III.

AMS 14C measurements for tree-ring samples from Japanese woods from 4c AD to 8c AD

International Nuclear Information System (INIS)

Ozaki, Hiromasa; Sakamoto, Minoru; Imamura, Mineo; Mitsutani, Takumi

2010-01-01

Regional offsets of atmospheric 14 C concentration, as represented by differences from IntCal calibration datasets, are discussed at times in relation to universal use of international radiocarbon calibration curve. In the construction of IntCal, 14 C contents of contemporaneous tree-ring samples from different regions in the northern hemisphere have been used, because the regional differences were indistinguishable from errors of measurements. Nowadays, high-precision 14 C results can be obtained much more easily than before, so more attention should be paid to the possible regional offsets. Most parts of IntCal has been constructed by using 14 C contents of tree-ring samples from woods in high latitude of Europe and North America, which are farthest from Japan in the northern hemisphere. So far, we have measured 14 C contents of tree-ring samples from Japanese wood samples dendrochronologically dated from 11th century BC to 4th century AD in order to investigate regional offset in Japan. Although the obtained results agreed well with IntCal in general, there were some periods when the 14 C contents differ significantly from IntCal. In this paper, we report the new results of AMS 14 C measurement for Japanese tree-ring samples ranging from 4th century AD to 8th century AD. The results show a significant disagreement with IntCal at around 630 AD. Similar difference was indicated by 14 C contents of tree-ring samples from other Japanese woods (Imamura et al., 2007). So it is certain that the regional offset in Japan exists at around 630 AD. (author)

NMR studies of echinomycin bisintercalation complexes with d(A1-C2-G3-T4) and d(T1-C2-G3-A4) duplexes in aqueous solution: sequence-dependent formation of Hoogsteen A1 x T4 and Watson-Crick T1 x A4 base pairs flanking the bisintercalation site

International Nuclear Information System (INIS)

Gao, X.; Patel, D.J.

1988-01-01

The authors report on two-dimensional proton NMR studies of echinomycin complexes with the self-complementary d(A1-C2-G3-Tr) and d(T1-C2-G3-A4) duplexes in aqueous solution. The exchangeable and nonexchangeable antibiotic and nucleic acid protons in the 1 echinomycin per tetranucleotide duplex complexes have been assigned from analyses of scalar coupling and distance connectivities in two-dimensional data sets records in H 2 O and D 2 O solution. An analysis of the intermolecular NOE patterns for both complexes combined with large upfield imino proton and large downfield phosphorus complexation chemical shift changes demonstrates that the two quinoxaline chromophores of echinomycin bisintercalate into the minor groove surrounding the dC-dG step of each tetranucleotide duplex. Further, the quinoxaline rings selectively stack between A1 and C2 bases in the d(ACGT) complex and between T1 and C2 bases in the d(TCGA) complex. The intermolecular NOE patterns and the base and sugar proton chemical shifts for residues C2 and G3 are virtually identical for the d(ACGT) and d(TCGA) complexes. A large set of intermolecular contacts established from nuclear Overhauser effects (NOEs) between antibiotic and nucleic acid protons in the echinomycin-tetranucleotide complexes in solution are consistent with corresponding contacts reported for echinomycin-oligonucleotide complexes in the crystalline state. The authors demonstrate that the G x G base pairs adopt Watson-Crick pairing in both d(ACGT) and d(TCGA) complexes in solution. By contrast, the A1 x T4 base pairs adopt Hoogsteen pairing for the echinomycin-d(A1-C2-G3-Tr) complex while the T1 x A4 base pairs adopt Watson-Crick pairing for the echinomycin-d(T1-C2-G3-A4) complex in aqueous solution. These results emphasize the role of sequence in discriminating between Watson-Crick and Hoogsteen pairs at base pairs flanking the echinomycin bisintercalation site in solution

rac-(1S,6S)-Methyl 6-methyl-2-oxobicyclo[4.1.0]heptane-1-carboxylate

DEFF Research Database (Denmark)

Juhl, Martin; Søtofte, Inger

2007-01-01

The crystal structure of the title compound, C10H14O3, was investigated as part of a study of the chemistry of nucleophilic 1,4-additions to highly electrophilic C=C double bonds. The cyclohexane ring adopts a half-chair conformation. The crystal packing is stabilized by van der Waals forces....

7-Chloro-11a-phenyl-2,3,5,10,11,11a-hexahydro-1H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11-dione

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Vahan Martirosyan

2008-03-01

Full Text Available The title compound, C18H15ClN2O2, is a potential human immunodeficiency virus type-1 (HIV-1 non-nucleoside reverse transcriptase inhibitor. The pyrrolidine ring adopts an envelope and the diazepine ring a boat conformation. In the crystal structure, two isomers (R and S form centrosymmetric dimers via N—H...O hydrogen bonds.

(3R,4R,4aS,7aR,12bS-3-Cyclopropylmethyl-4a,9-dihydroxy-3-methyl-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium bromide

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Xiangfeng Chen

2012-02-01

Full Text Available The title compound, C21H26NO4+·Br−, also known as R-methylnaltrexone (MNTX bromide, is a selective peripherally acting μ-opioid receptor antagonist with a oroxymorphone skeleton, synthesized by hydroxyl protection, N-methylation, deprotection and anion exchange of naltrexone. It comprises a five-ring system A/B/C/D/E. Rings C and E adopt distorted chair conformations, whereas ring D is in half-chair conformation. The C/E ring junctions are trans fused. The dihedral angle between rings D and E is 82.3 (1°, while the dihedral angles between the planes of rings C and A, and rings D and E are respectively 81.7 (1, 75.9 (1 and 12.2 (1°. In the crystal, molecules are linked by O—H...Br hydrogen bonds.

rac-6-Hydroxy-4-(4-nitrophenyl-5-(2-thienylcarbonyl-6-(trifluoromethyl-3,4,5,6-tetrahydropyrimidin-2(1H-one monohydrate

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Jian-Li Zhang

2010-11-01

Full Text Available The title compound, C16H12F3N3O5S·H2O, was prepared by reaction of 4-nitrobenzaldehyde, 4,4,4-trifluoro-1-(thiophen-2-ylbutane-1,3-dione and urea. The asymmetric unit contains two independent molecules, with essentially identical geometries and conformations. The dihydropyrimidine rings adopt a half-chair conformation. The dihedral angles between the benzene ring and the thiophene ring are 54.82 (8 and 58.72 (8° in the two molecules. The molecular conformation of one of the molecules is stabilized by two intramolecular O—H...O hydrogen bonds, generating an S(6 ring. The crystal structure is stabilized by intermolecular O—H...O and N—H...O hydrogen bonds.

Kleinian singularities and the ground ring of c=1 string theory

International Nuclear Information System (INIS)

Ghoshal, D.; Jatkar, D.P.; Mukhi, S.

1993-01-01

We investigate the nature of the ground ring of c=1 string theory at the special ADE points in the c=1 moduli space associated to discrete subgroups of SU(2). The chiral ground rings at these points are shown to define the ADE series of singular varieties introduced by Klein. The non-chiral ground rings relevant to closed-string theory are 3 real dimensional singular varieties obtained as U(1) quotients of the kleinian varieties. The unbroken symmetries of the theory at these points are the volume-preserving diffeomorphisms of these varieties. The theory of kleinian singularities has a close relation to that of complex hyperKaehler surfaces, or gravitational instantons. We speculate on the relevance of these instantons and of self-dual gravity in c=1 string theory. (orig.)

3-(4-Hexyloxyphenyl-1,2,4-triazolo[3,4-b]benzothiazole

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Dieter Schollmeyer

2014-03-01

Full Text Available The title compound, C20H21N3OS, was prepared by Huisgen reaction of 5-(4-hexyloxyphenyltetrazole and chlorobenzothiazole. The essentially planar benzothiazolotriazole framework [maximum deviation from the mean plane of 0.077 (1 Å for the bridgehead N atom] and the phenyl ring form a dihedral angle of 53.34 (5°. The hexyloxy chain adopts a gauche–all-anti conformation. The intracentroid separation of 3.7258 (8 Å between the triazole and benzene rings is the closest contact between individual molecules in the crystal.

Three closely related 4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridines: synthesis, molecular conformations and hydrogen bonding in zero, one and two dimensions.

Science.gov (United States)

Sagar, Belakavadi K; Harsha, Kachigere B; Yathirajan, Hemmige S; Rangappa, Kanchugarakoppal S; Rathore, Ravindranath S; Glidewell, Christopher

2017-03-01

In each of 1-(4-fluorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C 21 H 19 F 4 N 3 O 2 S, (I), 1-(4-chlorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C 21 H 19 ClF 3 N 3 O 2 S, (II), and 1-(3-methylphenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C 22 H 22 F 3 N 3 O 2 S, (III), the reduced pyridine ring adopts a half-chair conformation with the methylsulfonyl substituent occupying an equatorial site. Although compounds (I) and (II) are not isostructural, having the space groups Pbca and P2 1 2 1 2 1 , respectively, their molecular conformations are very similar, but the conformation of compound (III) differs from those of (I) and (II) in the relative orientation of the N-benzyl and methylsulfonyl substituents. In compounds (II) and (III), but not in (I), the trifluoromethyl groups are disordered over two sets of atomic sites. Molecules of (I) are linked into centrosymmetric dimers by C-H...π(arene) hydrogen bonds, molecules of (II) are linked by two C-H...O hydrogen bonds to form ribbons of R 3 3 (18) rings, which are themselves further linked by a C-Cl...π(arene) interaction, and a combination of C-H...O and C-H...π(arene) hydrogen bonds links the molecules of (III) into sheets. Comparisons are made with the structures of some related compounds.

5-[(1-Benzyl-1H-1,2,3-triazol-4-ylmethyl]-5H-dibenzo[b,f]azepine

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N. K. Lokanath

2013-12-01

Full Text Available In the title compound, C24H20N4, the azepine ring adopts a boat conformation. The dihedral angle between the benzene rings fused to the azepine ring is 49.40 (9°. The triazole ring makes a dihedral angle of 77.88 (9° with the terminal phenyl ring. In the crystal, molecules are linked via C—H...π interactions and a parallel slipped π–π interaction [centroid–centroid distance = 3.7324 (9, normal distance = 3.4060 (6 and slippage = 1.526 Å], forming a three-dimensional network.

5′-Methylsulfanyl-4′-oxo-7′-phenyl-3′,4′-dihydro-1′H-spiro[cyclohexane-1,2′-quinazoline]-8′-carbonitrile dimethylformamide monosolvate

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Xuan Liu

2011-08-01

Full Text Available In the title compound, C21H21N3OS·C3H7NO, the carbonitrile molecule is built up of two fused six-membered rings and one six-membered ring linked through a spiro C atom. The 1,3-diaza ring adopts an envelope conformation and the cyclohexane ring adopts a chair conformation. The dihedral angle between the aromatic rings is 46.7 (3°. In the crystal, the components are linked by N—H...O hydrogen bonds.

(3S,4S)-3-Ethyl-4-hydroxy-3-(3-methoxyphenyl)-1-methylazepan-1-ium d-tartrate dihydrate

OpenAIRE

Zhui-Bai Qiu; Bo Chao; Xing-Hai Wang

2008-01-01

In the title compound, C16H26NO2+·C4H5O6−·2H2O, a meptazinol derivative, three C atoms of the azepane ring are disordered over two positions, with site-occupancy factors of 0.80 and 0.20; the major disorder component adopts a twist-chair conformation, while the minor component has a chair conformation. The benzene ring is axially substituted on the heterocyclic ring, resulting in a folded conformation of the cation. The absolute configuration was determined with reference to d...

Crystal structure of 1-{3-(4-methylphenyl-5-[(E-2-phenylethenyl]-4,5-dihydro-1H-pyrazol-1-yl}ethan-1-one

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Farook Adam

2015-12-01

Full Text Available The title compound, C20H20N2O, was studied as a part of our work on pyrazoline derivatives. It represents a trans-isomer. The central pyrazoline ring adopts an envelope conformation with the asymmetric C atom having the largest deviation of 0.107 (1 Å from the mean plane. It forms dihedral angles of 6.2 (1 and 86.4 (1° with the adjacent p-tolyl and styrene groups, respectively. In the crystal, C—H...O interactions link molecules into infinite chains along the c axis.

(4-Chloroacetanilido-κ2N,Obis[2-(pyridin-2-ylphenyl-κ2C1,N]iridium(III

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Lijun Sun

2013-02-01

Full Text Available In the neutral mononuclear iridium(III title compound, [Ir(C8H7ClNO(C11H8N2], the IrIII atom adopts an octahedral geometry, and is coordinated by two 2-phenylpyridyl ligands and one anionic 4-chloroacetanilide ligand. The 2-phenylpyridyl ligands are arranged in a cis-C,C′ and cis-N,N′ fashion. Each 2-phenylpyridyl ligand forms a five-membered ring with the IrIII atom. The 2-phenylpyridyl planes are perpendicular to each other [dihedral angle = 89.9 (1°]. The Ir—C and Ir—N bond lengths are comparable to those reported for related iridium(III 2-phenylpyridyl complexes. The remaining two coordination sites are occupied by the amidate N and O atoms, which form a four-membered ring with the iridium atom (Ir—N—C—O. The amidate plane is nearly perpendicular to both 2-phenylpyridyl ligands [dihedral angles = 87.8 (2 and 88.3 (2°].

N,N′-Dicyclohexylnaphthalene-1,8;4:5-dicarboximide

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Manju Rajeswaran

2008-09-01

Full Text Available The title compound, C26H26N2O4, synthesized by the reaction of naphthalene-1,4,5,8-tetracarboxylic acid anhydride and cyclohexylamine, exhibits good n-type semiconducting properties. Accordingly, thin-film transistor devices comprising this compound show n-type behavior with high field-effect electron moblity ca 6 cm2/Vs [Shukla, Nelson, Freeman, Rajeswaran, Ahearn, Meyer & Carey(2008. Chem. Mater. Submitted]. The asymmetric unit comprises one-quarter of the centrosymmetric molecule in which all but two methylene C atoms of the cyclohexane ring lie on a mirror plane; the point-group symmetry is 2/m. The naphthalenediimide unit is strictly planar, and the cyclohexane rings adopt chair conformations with the diimide unit in an equatorial position on each ring.

Positron Options for the Linac-Ring LHeC

CERN Document Server

Zimmermann, F; Papaphilippou, Y; Schulte, D; Sievers, P; Rinolfi, L; Variola, A; Zomer, F; Braun, H H; Yakimenko, V; Bulyak, E V; Klein, M

2012-01-01

The full physics program of a future Large Hadron electron Collider (LHeC) [1] requires both pe+ and pe− collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8 × 1015 or 4.4 × 1016 e+/s at the collision point, which is about 300 or 7000 times the rate previously obtained, at the SLAC Linear Collider (SLC). We consider providing this e+ rate through a combination of measures: (1) Reducing the required production rate from the e+ target through colliding e+ (and the LHC protons) several times before deceleration, by reusing the e+ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, slicedrod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coher...

A versatile synthesis of cyclic dipeptides using the stepwise construction of the piperazine-2,5-dione ring from simple precursors: synthetic sequence and the structure of a representative product, (3RS)-4-(2-allyl-3,5-dimethylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione.

Science.gov (United States)

Acosta Quintero, Lina M; Palma, Alirio; Cobo, Justo; Glidewell, Christopher

2018-02-01

A versatile synthesis of multiply substituted cyclic dipeptides has been designed, based on the stepwise construction of the piperazine-2,5-dione ring using molecular fragments from four different precursor molecules. Starting from substituted 2-allylanilines, reaction with methyl 2-bromo-2-phenylacetate yields the corresponding methyl 2-(2-allylanilino)-2-phenylacetates, which react with haloacetyl chlorides to give methyl 2-[N-(2-allylphenyl)-2-haloacetamido]-2-phenylacetates, which then undergo ring closure with benzylamine to yield the corresponding cyclic dipeptides of type 4-(2-allylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione. (3RS)-4-(2-Allyl-3,5-dimethylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione, C 28 H 28 N 2 O 2 , (IIId), crystallizes with Z' = 2 in the space group P2 1 /c; the allyl groups in the two independent molecules adopt different conformations and, in one of them, the allyl group is disordered over two sets of atomic sites having occupancies of 0.534 (4) and 0.466 (4). In both molecules, the piperazine-2,5-dione ring adopts a boat conformation, with the 3-phenyl ring in a quasi-axial site. The molecules of (IIId) are linked into a three-dimensional framework structure by a combination of three C-H...O hydrogen bonds and three C-H...π(arene) hydrogen bonds. Comparisons are made with some related structures.

Piperazin-1-ium 4-aminobenzoate monohydrate

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P. Sivakumar

2016-05-01

Full Text Available The asymmetric unit of the title hydrated salt, C4H11N2+·C7H6NO2−·H2O, contains a piperazin-1-ium cation, a 4-aminobenzoate anion and a water molecule. One NH group of the piperazine ring is protonated and this ring adopts a chair conformation. The anion of this salt is generated by deprotonation of the OH group of the carboxylic acid substituent of 4-aminobenzoic acid. The benzene ring makes a dihedral angle of 2.6 (2° with the carboxylate substituent. The anion and the solvent water molecule are linked by an N—H...O hydrogen bond. Additional N—H...O and O—H...O hydrogen bonds connect adjacent anions through the water molecules, generating a two-dimensional network parallel to (100, forming R33(12 ring motifs. Adjacent cations are linked by N—H...N hydrogen bonds into infinite chains along (001. These chains are linked to the two-dimensional network of anions and water molecules by another N—H...O hydrogen bond, forming a three-dimensional network.

Crystal structure of methyl 3′-benzamido-4′-(4-methoxyphenyl-1′-methylspiro[indeno[1,2-b]quinoxaline-11,2′-pyrrolidine]-3′-carboxylate

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Kuppan Chandralekha

2016-09-01

Full Text Available In the title compound, C35H30N4O3, the spiro C atom connects the five-membered pyrrolidine ring and the indenoquinoxaline ring system. The pyrrolidine ring adopts a twist conformation. An intramolecular N—H...N interaction between the amino group and the pyrazine ring is observed. In the crystal, molecules are linked by a pairs of C—H...O hydrogen bonds, forming inversion dimers.

3-Hydroxy-2-[(4-hydroxy-3,5-dimethoxyphenyl(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-ylmethyl]-5,5-dimethylcyclohex-2-en-1-one

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Xiao-Hui Yang

2011-02-01

Full Text Available In the title compound, C25H32O7, the 3-hydroxy-5,5-dimethylcyclohex-2-enone rings adopt slightly distorted envelope conformations with the two planes at the base of the envelope forming dihedral angles of 57.6 (4 and 53.9 (9° with the benzene ring. There is an intramolecular hydroxy–ketone O—H...O interaction between the two substituted cyclohexane rings as well as a short intramolecular phenol–methoxy O—H...O interaction.

Butane-1,4-diyl bis(pyridine-4-carboxylate

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J. Muthukumaran

2011-07-01

Full Text Available The molecule of the title compound, C16H16N2O4, lies about an inversion centre; the butane chain adopts an extended zigzag conformation. The dihedral angle between the pyridine ring and the adjacent COO group is 3.52 (s14°.

Ethyl 2-(1,2,3,4-tetrahydro­spiro­[carba­zole-3,2′-[1,3]dioxolan]-9-yl)acetate

Science.gov (United States)

Löffler, Philipp M. G.; Ulven, Trond; Bond, Andrew D.

2009-01-01

In the title compound, C18H21NO4, the hydrogenated six-membered ring of the carbazole unit adopts a half-chair conformation. The dioxolane ring and ethyl­acetate substituent point to opposite sides of the carbazole plane. The ethyl­acetate substituent adopts an essentially fully extended conformation, and its mean plane forms a dihedral angle of 83.8 (1)° with respect to the carbazole mean plane. The mol­ecules are arranged into stacks in which the carbazole planes form a dihedral angle of 4.4 (1)° and have an approximate inter­planar separation of 3.6 Å. PMID:21582427

t-3-Benzyl-r-2,c-6-diphenylpiperidin-4-one oxime

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R. Arulraj

2016-12-01

Full Text Available In the title compound, C24H24N2O [systematic name: (E-3-benzyl-2,6-diphenylpiperidin-4-one oxime], the piperidine ring adopts a slightly distorted chair conformation and the phenyl rings and the benzyl group substituents are attached equatorially. The oxime group makes a dihedral angle of 42.88 (12° with the piperidine ring. The dihedral angle between the phenyl rings is 71.96 (8°. The benzyl ring makes dihedral angles of 63.01 (8 and 59.35 (8° with the two phenyl rings. In the crystal, molecules are linked by O—H...N hydrogen bonds, forming C(7 chains along the c axis. The chains are linked by C—H...π interactions, forming slabs lying parallel to the bc plane.

Design of new anti-Alzheimer drugs: ring-expansion synthesis and synchrotron X-ray diffraction study of dimethyl 4-ethyl-11-fluoro-1,4,5,6,7,8-hexahydroazonino[5,6-b]indole-2,3-dicarboxylate

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Flavien A. A. Toze

2018-03-01

Full Text Available The title compound, C20H23FN2O4, is the product of a ring-expansion reaction from a seven-membered fluorinated hexahydroazepine to a nine-membered azonine. The nine-membered azonine ring of the molecule adopts a chair–boat conformation. The C=C and C—N bond lengths [1.366 (3 and 1.407 (3 Å, respectively] indicate the presence of conjugation within the enamine CH2—C=C—N—CH2 fragment. The substituent planes at the C=C double bond of this fragment are twisted by 16.0 (3° as a result of steric effects. The amine N(Et N atom has a trigonal–pyramidal configuration (sum of the bond angles = 346.3°. The interplanar angle between the two carboxylate substituents is 60.39 (8°. In the crystal, molecules form zigzag chains along [010] by intermolecular N—H...O hydrogen-bonding interactions, which are further packed in stacks toward [100]. The title azoninoindole might be considered as a candidate for the design of new Alzheimer drugs.

2-Phenyl-7-(4-pyridylmethylamino-1,2,4-triazolo[1,5-a][1,3,5]triazin-5(4H-oneFused heterocyclic systems with s-triazine ring. Part 17. For part 16, see Dolzhenko et al. (2011.

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Lip Lin Koh

2011-01-01

Full Text Available In the title compound, C16H13N7O, the 1,2,4-triazolo[1,5-a][1,3,5]triazine heterocyclic system is essentially planar (r.m.s. deviation = 0.0375 Å. The attached benzene ring lies almost in the mean plane of 1,2,4-triazolo[1,5-a][1,3,5]triazine [dihedral angle = 1.36 (23°], while the pyridine ring is turned out of this plane by the aminomethyl bridge [dihedral angle = 69.22 (9°]. The amino group H atom is involved in intramolecular hydrogen bonding with a triazole N atom. In the crystal, molecules are connected via C(=ONH...N hydrogen bonds into C(11 chains parallel to [100]. The amino group H atom acts as a hydrogen-bond donor, forming an NH...O=C hydrogen bond with the carbonyl O atom, which links the molecules into C(6 chains running along [011] and [01overline{1}].

Ethyl 2-(2,5-dioxo-4,4-diphenylimidazolidin-1-ylacetate

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Youssef Ramli

2017-01-01

Full Text Available The five-membered ring of the title compound, C19H18N2O4, adopts an envelope conformation. In the crystal, pairwise N—H...O hydrogen bonds form centrosymmetric dimers which are connected into chains parallel to the c-axis direction by pairwise C—H...O hydrogen bonds. A second set of C—H...O hydrogen bonds links these chains into sheets oriented parallel to (100. A combination of additional C—H...O hydrogen bonds and C—H...π(ring interactions combine the sheets into a three-dimensional network.

(1R,2R,3R,4R,5S-2,3-Bis[(2S′-2-acetoxy-2-phenylacetoxy]-4-azido-1-[(2,4-dinitrophenylhydrazonomethyl]bicyclo[3.1.0]hexane

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Robert McDonald

2008-02-01

Full Text Available In the title compound, C38H29N7O12, the five-membered ring adopts an envelope conformation in which the `flap' is cis to the cyclopropane group. This conformation is similar to those of other bicyclo[3.1.0]hexane analogues for which crystal structures have been reported. The absolute configuration of the stereogenic centers on the cyclopentane ring, as determined by comparison with the known configurations of the stereogenic centers in the (2S-2-acetoxy-2-phenylacetoxy groups, is 1(R, 2(R, 3(R, 4(R and 5(S. An intramolecular N—H...O hydrogen bond is present.

4-(2,3-Dihydroxybenzylideneamino-3-methyl-1H-1,2,4-triazol-5(4H-one

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Şamil Işık

2009-12-01

Full Text Available All the non-H atoms of the title compound, C10H10N4O3, are almost coplanar, the maximum deviation from planarity being 0.065 (3 Å. The dihedral angle between the aromatic rings is 1.66 (6°. The molecule adopts the enol–imine tautomeric form with an intramolecular hydrogen-bonding interaction between the Schiff base N atom and the hydroxy group. In the crystal, intermolecular N—H...O and O—H...O hydrogen bonds link the molecules into a three-dimensional network.

Synthesis of a cleavable heterobifunctional photolabelling reagent: ring-labelled 3-((4-azidophenyl)dithio)propionic acid- sup 14 C

Energy Technology Data Exchange (ETDEWEB)

Ramaswami, Varadarajan (Carnegie-Mellon Univ., Pittsburgh, PA (USA). Dept. of Chemistry); Tirrell, D.A. (Massachusetts Univ., Amherst, MA (USA). Dept. of Polymer Science and Engineering)

1989-08-01

An efficient synthesis of ring-labelled 3-((4-azidophenyl)dithio)propionic acid-{sup 14}C is described. Chlorosulfonation of uniformly ring-labelled acetanilide-{sup 14}C followed by reductive dimerization of the sulfonyl chloride with HI afforded 4-acetamidophenyl disulfide. Hydrolysis and diazotization then gave 4-azidophenyl disulfide, which was converted to the title compound via the sulfur transfer reagent N-(4-azidophenylthio)phthalimide. The overall yield of 3-((4-azidophenyl)dithio)propionic acid-{sup 14}C was 22%. 3-((4-Azidophenyl)dithio)propionic acid-{sup 14}C is a cleavable heterobifunctional photolabelling reagent of potential utility in studies of biomembrane structure and intermacromolecular interaction. (author).

Synthesis of the EF-ring of ciguatoxin 3C based on the [2,3]-Wittig rearrangement and ring-closing olefin metathesis.

Science.gov (United States)

Goto, Akiyoshi; Fujiwara, Kenshu; Kawai, Ayako; Kawai, Hidetoshi; Suzuki, Takanori

2007-12-20

The EF-ring segment of ciguatoxin 3C, a causative toxin of ciguatera fish poisoning, was synthesized in three major steps: 1,4-addition for the C20O-C27 bond connection, chirality transferring anti selective [2,3]-Wittig rearrangement for the construction of the anti-2-hydroxyalkyl ether part, and ring-closing olefin metathesis for the F-ring formation.

Investigations into the construction of the pentasubstituted ring C of Neosurugatoxin – a crystallographic study

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Alan M. Jones

2016-01-01

Full Text Available The crystal structures of three cyclopenta[c]furans with various substituents at the 4-, 5- and 6-positions of the ring system are reported, namely, (±-(3aR,4S,5S,6aS-4-methyl-5-phenylhexahydro-1H-cyclopenta[c]furan-4,5-diol, C14H18O3, (I, (±-(3aR,4S,5S,6aS-4-benzyloxy-4-methyl-5-phenylhexahydro-1H-cyclopenta[c]furan-5-ol, C21H24O3, (II, and (±-(1aR,1bS,4aR,5S,5aR-5-benzyloxy-5-methyl-5a-phenylhexahydro-2H-oxireno[2′,3′:3,4]cyclopenta[1,2-c]furan, C21H22O3, (III. The dominant interaction in (I and (II is an O—H...O hydrogen bond across the bicyclic 5,5-ring system between the non-functionalized hydroxy group and the tetrahydrofuran O atom, which appears to influence the envelope conformations of the fused five-membered rings, whereas in (III, the rings have different conformations. A weak intramolecular C—H...O interaction appears to influence the degree of tilt of the phenyl ring attached to the 5-position and is different in (I compared to (II and (III.

The c-Ring of the F1FO-ATP Synthase: Facts and Perspectives.

Science.gov (United States)

Nesci, Salvatore; Trombetti, Fabiana; Ventrella, Vittoria; Pagliarani, Alessandra

2016-04-01

The F1FO-ATP synthase is the only enzyme in nature endowed with bi-functional catalytic mechanism of synthesis and hydrolysis of ATP. The enzyme functions, not only confined to energy transduction, are tied to three intrinsic features of the annular arrangement of c subunits which constitutes the so-called c-ring, the core of the membrane-embedded FO domain: (i) the c-ring constitution is linked to the number of ions (H(+) or Na(+)) channeled across the membrane during the dissipation of the transmembrane electrochemical gradient, which in turn determines the species-specific bioenergetic cost of ATP, the "molecular currency unit" of energy transfer in all living beings; (ii) the c-ring is increasingly involved in the mitochondrial permeability transition, an event linked to cell death and to most mitochondrial dysfunctions; (iii) the c subunit species-specific amino acid sequence and susceptibility to post-translational modifications can address antibacterial drug design according to the model of enzyme inhibitors which target the c subunits. Therefore, the simple c-ring structure not only allows the F1FO-ATP synthase to perform the two opposite tasks of molecular machine of cell life and death, but it also amplifies the enzyme's potential role as a drug target.

Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octahydro-1aH-1-oxacyclopropa[d]naphthalen-7-ylacrylate

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Mohamed Tebbaa

2012-02-01

Full Text Available The title compound, C16H20O5, was synthesized from ilicic acid [2-(8-hydroxy-4a,8-dimethyldecahydronaphthalen-2-ylacrylic acid], which was isolated from the chloroform extract of the aerial part of Inula viscose (L Aiton [or Dittrichia viscosa (L Greuter]. The molecule is built up from two fused six-membered rings, the epoxidized six-membered ring adopts a half-chair conformation while the other ring displays a perfect chair conformation. The crystal structure features C—H...O hydrogen bonds.

1,10,10-Trimethyl-5-phenyl-3-oxa-4-azatricyclo[5.2.1.02,6]dec-4-en-2-ol

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Moha Berraho

2013-08-01

Full Text Available The title compound, C17H21NO2, was synthesized by the reaction of (1R-(+-3-benzylcamphor and hydroxylamine. The oxazole ring makes a dihedral angle of 23.42 (16° with the phenyl ring. The six-membered ring of the norboryl group adopts a boat conformation, whereas each of the five-membered rings of the norboryl group displays a flattened envelope conformation, with the C atom carrying the methyl groups representing the flap for both rings. In the crystal, molecules are linked into zigzag chains propagating along the b axis by O—H...N hydrogen bonds.

13-Hydroxy-4,16-dimethyl-4,16-diazapentacyclo[12.3.1.01,5.05,13.07,12]octadeca-7(12,8,10-triene-6,18-dione

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K. Gurunathan

2009-05-01

Full Text Available In the title compound, C18H20N2O3, the N-methylpiperidone ring adopts a chair conformation. The pyrrolidine ring and the five-membered cyclopentane rings adopt envelope conformations. The five-membered ring of the ninhydrin system adopts an envelope conformation with the central C atom deviating by 0.217 (1Å from the mean plane through the other atoms. The molecular packing is characterized by intermolecular C—H...O and intramolecular C—H...O and O—H...N interactions.

1-(3,4-Difluorobenzyl-4-(4-methylphenylsulfonylpiperazine

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S. Sreenivasa

2013-07-01

Full Text Available In the title compound, C18H20F2N2O2S, the central piperazine ring adopts a chair conformation. The dihedral angle between the two benzene rings is 40.20°, whereas those between the piperazine ring (considering the best fit plane through all the non-H atoms and the sulfonyl-bound benzene and difluorobenzene rings are 74.96 and 86.16°, respectively. In the crystal, molecules are stacked along the a axis through weak C—H...O and C—H...F interactions.

Spectral Properties of Novel 1,3-oxazol-5(4H)-ones With Substituted Benzylidene and Phenyl Rings

DEFF Research Database (Denmark)

Palcut, Marián

2009-01-01

In the present work, five novel (4Z)-4-benzylidene-2-phenyl-1,3-oxazol-5(4H)-ones (azlactones) were investigated by the infra-red (IR) and nuclear magnetic resonance spectroscopy (NMR) of the 1H and 13C nuclei. The spectral properties of the oxazolone ring were monitored with respect to the subst...

Ethyl 2,6-bis(4-chlorophenyl-4-(4-methylanilino-1-(4-methylphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate

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Vivek K. Gupta

2013-03-01

Full Text Available In the title molecule, C34H32Cl2N2O2, the tetrahydropyridine ring adopts a distorted boat conformation and both 4-chlorophenyl substituents are in axial positions. An intramolecular N—H...O hydrogen bond is formed by the amino group and carbonyl O atom. In the crystal, weak C—H...Cl interactions link the molecules into chains along [010].

4′-Methyl-1H-14′,19′-dioxa-4′-azaspiro[indole-3,5′-tetracyclo[18.4.0.02,6.08,13]tetracosane]-1′(24′,8′,10′,12′,20′,22′-hexaene-2,7′(3H-dione

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Sibi Narayanan

2012-12-01

Full Text Available In the title compound, C29H28N2O4, the indoline ring system is essentially planar, with a maximum deviation of 0.027 (2 Å; the carbonyl O atom lies 0.102 (1 Å out of the least-squares plane of the indole ring. The pyrrolidine ring adopts a C-envelope conformation, with a C atom displaced by 0.643 (2 Å from the mean plane formed by the remaining ring atoms. The pyrrolidine ring makes a dihedral angle of 86.1 (8° with the indoline ring system. In the crystal, N—H...O hydrogen bonds result in the formation of cyclic centrosymmetric dimers [R22(8]. C—H...π interactions also occur, leading to a chain along the b-axis direction. There is a rather weak π–π electron interaction between the pyrrazole and benzene rings, with a centroid–centroid distance of 3.765 (1 Å.

5-(4-Methylphenylsulfonyl-1,3-dithiolo[4,5-c]pyrrole-2-thione

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Ning-Juan Zheng

2012-04-01

Full Text Available The asymmetric unit of the title compound, C12H9NO2S4, contains one half-molecule with the N, two S amd four C atoms lying on a mirror plane. The molecule exhibits a V-shaped conformation, with a dihedral angle of 87.00 (7° between the benzene and dithiolopyrrole rings. The methyl group was treated as rotationally disordered between two orientations in a 1:1 ratio. In the crystal, weak C—H...O hydrogen bonds link the molecules into chains in [010].

4,4′-Dimethoxy-2,2′-[(butane-1,4-diyldioxybis(nitrilomethylidyne]diphenol

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Yin-Xia Sun

2010-11-01

Full Text Available The title Schiff base bisoxime compound, C20H24N2O6, lies across an inversion centre and adopts an E configuration with respect to the C=N bond. In the molecule, the oxime group is roughly coplanar with the benzene ring, forming a dihedral angle of 1.77 (2°. An intramolecular O—H...N hydrogen bond forms a six-membered ring with an S(6 motif. Weak intermolecular C—H...O hydrogen bonding is present in the crystal structure.

Racemic methyl 3,10-dioxa-2-azatricyclo[6.2.1.02,6]undecane-4- carboxylate

KAUST Repository

Moosa, Basem; Fazal, Atif; Ali, Shaikh A.; Fettouhi, Mohammed

2011-01-01

The structure of the racemic title compound, C10H 15NO4, consists of a tricyclic skeleton comprising a six-membered piperidine ring and five-membered isoxazolidine and tetrahydrofuran rings. The piperidine ring adopts a distorted chair conformation

6-Methoxy-1-(4-methoxyphenyl-1,2,3,4-tetrahydro-9H-β-carbolin-2-ium acetate

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Mohd Mustaqim Rosli

2012-05-01

Full Text Available In the title compound, C19H21N2O2+·C2H3O2−, the 1H-indole ring system is essentially planar [maximum deviation = 0.0257 (14 Å] and forms a dihedral angle of 87.92 (7 Å with the benzene ring attached to the tetrahydropyridinium fragment. The tetrahydropyridinium ring adopts a half-chair conformation. In the crystal, cations and anions are linked by interionic N—H...O, C—H...O and C—H...N hydrogen bonds into chains along the a axis.

6-Chloro-3-[5-(3-methoxy-8-methyl-4-quinolyl-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-2-methyl-4-phenylquinoline

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Hoong-Kun Fun

2009-11-01

Full Text Available In the title compound, C36H29ClN4O, the dihydropyrazole ring adopts an envelope conformation. The two quinoline ring systems (r.m.s. deviations = 0.029 and 0.018 Å are oriented at a dihedral angle of 71.43 (4°. One of the quinoline rings makes a dihedral angle of 65.40 (7° with the phenyl substituent. In the crystal, molecules are linked into chains along the b axis by intermolecular C—H...N hydrogen bonds. In addition, C—H...π and π–π [centroid–centroid distance = 3.7325 (8 Å] interactions are observed.

Bis[2-(1,3-benzothiazol-2-ylphenyl-κ2C1,N][1,3-bis(4-bromophenylpropane-1,3-dionato-κ2O,O′]iridium(III

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Sung Kwon Kang

2013-08-01

Full Text Available The title complex, [Ir(C15H9Br2O2(C13H8NS2], lies about a crystallographic twofold rotation axis passing through the IrIII atom and the central C atom of the bis(bromophenylpropane-1,3-dionate ligand. The IrIII atom adopts a distorted octahedral geometry coordinated by two N atoms in the axial positions, and two C and two O atoms in the equatorial plane. The dihedral angle between the two thiazole ring systems in the complex is 77.45 (10°.

4,4′-([4,4′-Bipyridine]-1,1′-diium-1,1′-diyldibenzoate dihydrate

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Mark A. Rodriguez

2016-06-01

Full Text Available We report here the synthesis of a neutral viologen derivative, C24H16N2O4·2H2O. The non-solvent portion of the structure (Z-Lig is a zwitterion, consisting of two positively charged pyridinium cations and two negatively charged carboxylate anions. The carboxylate group is almost coplanar [dihedral angle = 2.04 (11°] with the benzene ring, whereas the dihedral angle between pyridine and benzene rings is 46.28 (5°. The Z-Lig molecule is positioned on a center of inversion (Fig. 1. The presence of the twofold axis perpendicular to the c-glide plane in space group C2/c generates a screw-axis parallel to the b axis that is shifted from the origin by 1/4 in the a and c directions. This screw-axis replicates the molecule (and solvent water molecules through space. The Z-Lig molecule links to adjacent molecules via O—H...O hydrogen bonds involving solvent water molecules as well as intermolecular C—H...O interactions. There are also π–π interactions between benzene rings on adjacent molecules.

Critical contribution of aromatic rings to specific recognition of polyether rings. The case of ciguatoxin CTX3C-ABC and its specific antibody 1C49.

Science.gov (United States)

Tsumoto, Kouhei; Yokota, Akiko; Tanaka, Yoshikazu; Ui, Mihoko; Tsumuraya, Takeshi; Fujii, Ikuo; Kumagai, Izumi; Nagumo, Yoko; Oguri, Hiroki; Inoue, Masayuki; Hirama, Masahiro

2008-05-02

To address how proteins recognize polyether toxin compounds, we focused on the interaction between the ABC ring compound of ciguatoxin 3C and its specific antibody, 1C49. Surface plasmon resonance analyses indicated that Escherichia coli-expressed variable domain fragments (Fv) of 1C49 had the high affinity constants and slow dissociation constants typical of antigen-antibody interactions. Linear van't Hoff analyses suggested that the interaction is enthalpy-driven. We resolved the crystal structure of 1C49 Fv bound to ABC ring compound of ciguatoxin 3C at a resolution of 1.7A. The binding pocket of the antibody had many aromatic rings and bound the antigen by shape complementarity typical of hapten-antibody interactions. Three hydrogen bonds and many van der Waals interactions were present. We mutated several residues of the antibody to Ala, and we used surface plasmon resonance to analyze the interactions between the mutated antibodies and the antigen. This analysis identified Tyr-91 and Trp-96 in the light chain as hot spots for the interaction, and other residues made incremental contributions by conferring enthalpic advantages and reducing the dissociation rate constant. Systematic mutation of Tyr-91 indicated that CH-pi and pi-pi interactions between the aromatic ring at this site and the antigen made substantial contributions to the association, and van der Waals interactions inhibited dissociation, suggesting that aromaticity and bulkiness are critical for the specific recognition of polyether compounds by proteins.

Racemic methyl 3,10-dioxa-2-azatricyclo[6.2.1.02,6]undecane-4- carboxylate

KAUST Repository

Moosa, Basem

2011-04-29

The structure of the racemic title compound, C10H 15NO4, consists of a tricyclic skeleton comprising a six-membered piperidine ring and five-membered isoxazolidine and tetrahydrofuran rings. The piperidine ring adopts a distorted chair conformation, while the isoxazolidine and tetrahydrofuran rings have envelope conformations.

meso-4,4′-Dimethoxy-2,2′-{[(3aR,7aS-2,3,3a,4,5,6,7,7a-octahydro-1H-benzimidazole-1,3-diyl]bis(methylene}diphenol

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Augusto Rivera

2013-07-01

Full Text Available The title compound, C23H30N2O4, a di-Mannich base derived from 4-methoxyphenol and cis-1,2-diaminecyclohexane, has a perhydrobenzimidazolidine nucleus, in which the cyclohexane ring adopts a chair conformation and the heterocyclic ring has a half-chair conformation with a C—N—C—C torsion angles of −48.14 (15 and −14.57 (16°. The mean plane of the heterocycle makes dihedral angles of 86.29 (6 and 78.92 (6° with the pendant benzene rings. The molecular structure of the title compound shows the presence of two interactions between the N atoms of the imidazolidine ring and the hydroxyl groups through intramolecular O—H...N hydrogen bonds with graph-set motif S(6. The unobserved lone pairs of the N atoms are presumed to be disposed in a syn conformation, being only the second example of an exception to the typical `rabbit-ears' effect in 1,2-diamines.

3-Benzyl-4-ethyl-1H-1,2,4-triazole-5(4H)-thione.

Science.gov (United States)

Karczmarzyk, Zbigniew; Pitucha, Monika; Wysocki, Waldemar; Pachuta-Stec, Anna; Stańczuk, Andrzej

2013-02-01

The title compound, C(11)H(13)N(3)S, exists in the 5-thioxo tautomeric form. The benzene ring exhibits disorder with a refined ratio of 0.77 (2):0.23 (2) for components A and B with a common bridgehead C atom. The 1,2,4-triazole ring is essentially planar, with a maximum deviation of 0.002 (3) Å for the benzyl-substituted C atom, and forms dihedral angles of 88.94 (18) and 86.56 (49)° with the benzene rings of components A and B, respectively. The angle between the plane of the ethyl chain and the mean plane of 1,2,4-triazole ring is 88.55 (15)° and this conformation is stabilized by an intra-molecular C-H⋯S contact. In the crystal, pairs of N-H⋯S hydrogen bonds link mol-ecules into inversion dimers. π-π inter-actions are observed between the triazole and benzene rings, with centroid-centroid separations of 3.547 (4) and 3.544 (12) Å for components A and B, and slippages of 0.49 (6) and 0.58 (15) Å, respectively.

Racemic methyl 3,10-dioxa-2-azatricyclo[6.2.1.02,6]undecane-4-carboxylate

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Basem A. Moosa

2011-05-01

Full Text Available The structure of the racemic title compound, C10H15NO4, consists of a tricyclic skeleton comprising a six-membered piperidine ring and five-membered isoxazolidine and tetrahydrofuran rings. The piperidine ring adopts a distorted chair conformation, while the isoxazolidine and tetrahydrofuran rings have envelope conformations.

Crystal structure of 1,4-bis(3-ammoniopropylpiperazine-1,4-diium bis[dichromate(VI

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S. Vetrivel

2016-05-01

Full Text Available The asymmetric unit of the organic–inorganic title salt, (C10H28N4[Cr2O7]2, comprises one half of an 1,4-bis(3-ammoniopropylpiperazinediium cation (the other half being generated by the application of inversion symmetry and a dichromate anion. The piperazine ring of the cation adopts a chair conformation, and the two CrO4 tetrahedra of the anion are in an almost eclipsed conformation. In the crystal, the cations and anions form a layered arrangement parallel to (001. N—H...O hydrogen bonds between the cations and anions and additional C—H...O interactions lead to the formation of a three-dimensional network structure.

3-Ethyl-4-[(E-(4-fluorobenzylideneamino]-1H-1,2,4-triazole-5(4H-thione

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Alphonsus D'souza

2012-05-01

Full Text Available In the title compound, C11H11FN4S, the dihedral angle between the 1,2,4-triazole ring and the benzene ring is 25.04 (12° and an intramoleuclar C—H...S interaction leads to an S(6 ring. In the crystal, inversion dimers linked by pairs of N—H...S hydrogen bonds generate R22(8 loops.

1,3-Di-4-pyridylpropane–4,4′-oxydibenzoic acid (1/1

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Hirofumi Hinode

2008-12-01

Full Text Available The hydrothermal reaction of Cd(NO32·4H2O, 1,3-di-4-pyridylpropane (BPP and 4,4′-oxydibenzoic acid (OBA led to the formation of the title compound, C13H14N2·C14H10O5. The asymmetric unit consists of one molecule of OBA and one of BPP. In the OBA molecule, one COOH group is nearly planar with its attached benzene ring [dihedral angle = 0.9 (1°], while the other COOH group is slightly twisted with a dihedral angle of 10.8 (3°. The carboxyl groups form strong intermolecular O—H...N hydrogen bonds with N atoms of the pyridine rings in BPP, linking the molecules into zigzag chains.

Methyl (9aR*,10S*,11R*,13aS*,13bS*-9-oxo-6,7,9,9a,10,11-hexahydro-5H,13bH-11,13a-epoxypyrrolo[2′,1′:3,4][1,4]diazepino[2,1-a]isoindole-10-carboxylate

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Flavien A. A. Toze

2011-11-01

Full Text Available The title compound, C17H18N2O4, is the methyl ester of the adduct of intramolecular Diels–Alder reaction between maleic anhydride and 1-(2-furyl-2,3,4,5-tetrahydro-1H-pyrrolo[1,2-a][1,4]diazepine. The molecule comprises a fused pentacyclic system containing four five-membered rings (viz. pyrrole, 2-pyrrolidinone, tetrahydrofuran and dihydrofuran and one seven-membered ring (1,4-diazepane. The pyrrole ring is approximately planar (r.m.s. deviation = 0.003 Å while the 2-pyrrolidinone, tetrahydrofuran and dihydrofuran five-membered rings have the usual envelope conformations. The central seven-membered diazepane ring adopts a boat conformation. In the crystal, molecules are bound by weak intermolecular C—H...O hydrogen-bonding interactions into zigzag chains propagating in [010]. In the crystal packing, the chains are stacked along the a axis.

4,4′-Dimethoxy-2,2′-{[(3aRS,7aRS-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene}diphenol

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Augusto Rivera

2011-09-01

Full Text Available The title compound, C23H30N2O4, is a Mannich base useful for studying the effect of an electron-donating phenol substituent on intramolecular hydrogen bonding. In the molecular structure, the cyclohexane ring adopts a chair conformation and the five-membered ring has a twisted envelope conformation. Each methoxy group is oriented in the same plane of the respective aromatic ring, showing torsion angles below 11.8 (3° and bond angles between the methoxy group and the aromatic ring of 116.6 (2 and 116.6 (1°. The structure shows interactions between two the N atoms of the heterocyclic ring and the hydroxy groups by intramolecular O—H...N hydrogen-bonding interactions. In the crystal, C—H...O interactions are observed. The crystal studied was a racemic mixture of RR and SS enantiomers.

1-[(4-Bromophenyl(morpholin-4-ylmethyl]naphthalen-2-ol

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Qun Zhao

2012-03-01

Full Text Available The title compound, C21H20BrNO2, was obtained via a one-pot synthesis from the reaction of 4-bromobenzaldehyde, 2-naphthol and morpholine. In the asymmetric unit, there are four molecules with similar structures. The morpholine ring adopts a chair conformation, and the hydroxy group links with the morpholine via an intramolecular O—H...N hydrogen bond. The bromophenyl ring is approximately perpendicular to the mean pane of the naphthalene system at dihedral angles of 76.7 (3, 81.4 (3, 79.7 (3 and 84.5 (3° in the four independent molecules. Weak C—H...O hydrogen bonds are observed in the crystal.

(3S,4S)-3-Ethyl-4-hydr-oxy-3-(3-methoxy-phen-yl)-1-methyl-azepan-1-ium d-tartrate dihydrate.

Science.gov (United States)

Wang, Xing-Hai; Chao, Bo; Qiu, Zhui-Bai

2008-04-02

In the title compound, C(16)H(26)NO(2) (+)·C(4)H(5)O(6) (-)·2H(2)O, a meptaz-inol derivative, three C atoms of the azepane ring are disordered over two positions, with site-occupancy factors of 0.80 and 0.20; the major disorder component adopts a twist-chair conformation, while the minor component has a chair conformation. The benzene ring is axially substituted on the heterocyclic ring, resulting in a folded conformation of the cation. The absolute configuration was determined with reference to d-tartaric acid. The crystal structure is stabilized by an extensive network of intra- and inter-molecular O-H⋯O hydrogen bonds.

4-[(3-Phenyl-4,5-dihydroisoxazol-5-ylmethyl]-2H-benzo[b][1,4]thiazin-3(4H-one

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Nada Kheira Sebbar

2016-06-01

Full Text Available In the title compound, C18H16N2O2S, the 5-dihydroisoxazol-5-yl ring and its phenyl substituent are nearly coplanar, with the largest deviation from the mean plane being 0.0184 (16 Å. The thiomorpholin-3-one ring adopts a screw-boat conformation and the attached benzene ring makes a dihedral angle of 42.26 (7° with the mean plane through the 3-phenyl-4,5-dihydroisoxazol-5-yl ring system. In the crystal, molecules are linked by pairs of C—H...N hydrogen bonds, forming inversion dimers. These dimers are linked via C—H...O hydrogen bonds, generating a three-dimensional network.

C and C* among intermediate rings

NARCIS (Netherlands)

Sack, J.; Watson, S.

2014-01-01

Given a completely regular Hausdorff space X, an intermediate ring A(X) is a ring of real valued continuous functions between C*(X) and C(X). We discuss two correspondences between ideals in A(X) and z-filters on X, both reviewing old results and introducing new results. One correspondence, ZA,

Tree-ring C-H-O isotope variability and sampling

International Nuclear Information System (INIS)

Leavitt, Steven W.

2010-01-01

In light of the proliferation of tree-ring isotope studies, the magnitude and cause of variability of tree-ring δ 13 C, δ 18 O and δ 2 H within individual trees (circumferential) and among trees at a site is examined in reference to field and laboratory sampling requirements and strategies. Within this framework, this paper provides a state-of-knowledge summary of the influence of 'juvenile' isotope effects, ageing effects, and genetic effects, as well as the interchangeability of species, choice of ring segment to analyze (whole ring, earlywood or latewood), and the option of sample pooling. The range of isotopic composition of the same ring among trees at a site is ca. 1-3 per mille for δ 13 C, 1-4 per mille δ 18 O, and 5-30 per mille for δ 2 H, whereas the circumferential variability within a tree is lower. A standard prescription for sampling and analysis does not exist because of differences in field environmental circumstances and mixed findings represented in relevant published literature. Decisions in this regard will usually be tightly constrained by goals of the study and project resources. Sampling 4-6 trees at a site while avoiding juvenile effects in rings near the pith seems to be the most commonly used methodology, and although there are some reasoned arguments for analyzing only latewood and developing separate isotope records from each tree, the existence of some contradictory findings together with efforts to reduce cost and effort have prompted alternate strategies (e.g., most years pooled with occasional analysis of rings in the sequence separately for each tree) that have produced useful results in many studies.

4′-Methyl-14′,19′-dioxa-4′-azaspiro[acenaphthylene-1,5′-tetracyclo[18.4.0.02,6.08,13]tetracosane]-1′(24′,8′,10′,12′,20′,22′-hexaene-2,7′(1H-dione

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Sibi Narayanan

2012-12-01

Full Text Available In the title compound, C33H29NO4, the acenaphthylene ring system is essentially planar (r.m.s. deviation = 0.0290 Å. The pyrrolidine ring adopts a C-envelope conformation with a C atom displaced by 0.671 (2 Å from the mean-plane formed by the remaining ring atoms. The pyrrolidine ring is fused to acenaphthylene ring system making a dihedral angle of 88.0 (7°. In the crystal, molecules are linked into R22(9 dimers via C—H...N and C—H...O hydrogen bonds. Two C atoms act as donors to the same O atom acceptor, resulting in the formation of R21(7 ring motifs. These two motifs combine to form hydrogen-bonded sheets running along the a- and b-axis directions.

1-[3-(4-Chlorophenyl-5-(4-methoxyphenyl-4,5-dihydro-1H-pyrazol-1-yl]ethanone

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Hoong-Kun Fun

2012-04-01

Full Text Available In the title compound, C18H17ClN2O2, the benzene rings form dihedral angles of 6.69 (6 and 74.88 (5° with the 4,5-dihydro-1H-pyrazole ring. The benzene rings form a dihedral angle of 76.67 (5° with each other. In the crystal, molecules are linked via bifurcated (C,C–H...O hydrogen bonds into chains along [010]. The crystal structure is further consolidated by C—H...π interactions.

Redox shuttles having an aromatic ring fused to a 1,1,4,4-tetrasubstituted cyclohexane ring

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Weng, Wei; Zhang, Zhengcheng; Amine, Khalil

2015-12-01

An electrolyte includes an alkali metal salt; an aprotic solvent; and a redox shuttle additive including an aromatic compound having at least one aromatic ring fused with at least one non-aromatic ring, the aromatic ring having two or more oxygen or phosphorus-containing substituents.

Isotypic crystal structures of 1-benzyl-4-(4-bromophenyl-2-imino-1,2,5,6,7,8,9,10-octahydrocycloocta[b]pyridine-3-carbonitrile and 1-benzyl-4-(4-fluorophenyl-2-imino-1,2,5,6,7,8,9,10-octahydrocycloocta[b]pyridine-3-carbonitrile

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R. A. Nagalakshmi

2014-11-01

Full Text Available The molecules of the two isotypic title compounds, C25H24BrN3, (I, and C25H24FN3, (II, comprise a 2-iminopyridine ring fused with a cyclooctane ring. In (I, the cyclooctane ring adopts a twisted chair–chair conformation, while in (II, this ring adopts a twisted boat–chair conformation. The dihedral angles between the planes of the pyridine ring and the bromobenzene and phenyl rings are 80.14 (12 and 71.72 (13°, respectively, in (I. The equivalent angles in (II are 75.25 (8 and 68.34 (9°, respectively. In both crystals, inversion dimers linked by pairs of C—H...N interactions generate R22(14 loops, which are further connected by weak C—H...π interactions, generating (110 sheets.

Crystal structure of chlorido(2-{1-[2-(4-chlorophenylhydrazin-1-ylidene-κN]ethyl}pyridine-κN(η5-pentamethylcyclopentadienylrhodium(III chloride

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Neelakandan Devika

2015-03-01

Full Text Available The cation of the title compound, [Rh(η5-C5Me5Cl(C13H12ClN3]Cl, adopts a typical piano-stool geometry. The complex is chiral at the metal and crystallizes as a racemate. Upon coordination, the hydrazinylidenepyridine ligand is non-planar, an angle of 54.42 (7° being observed between the pyridine ring and the aromatic ring of the [2-(4-chlorophenylhydrazin-1-ylidene]ethyl group. In the crystal, a weak interionic N—H...Cl hydrogen bond is observed.

Sulfonated 1,3-bis(4-pyridylpropane

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Ore Kuyinu

2011-06-01

Full Text Available In the title compound, 4-[3-(3-sulfonatopyridin-1-ium-4-ylpropyl]pyridin-1-ium-3-sulfonate, C13H14N2O6S2, the molecule is zwitterionic, with the sulfonic acid proton transfered to the basic pyridine N atom. Also, the structure adopts a butterfly-like conformation with the sulfonate groups on opposite sides of the `wings'. The dihedral angle between the two pyridinium rings is 83.56 (7°, and this results in the molecule having a chiral conformation and packing. There is strong intermolecular hydrogen bonding between the pyridinium H and sulfonate O atoms of adjoining molecules. In addition, there are weaker intermolecular C—H...O interactions.

Synthesis of 14C-labeled 3-{[1-ethoxycarbonyl-3-phenyl-(1S)-propyl]amino}-2,3,4,5-tetrahydro-2-oxo -1H-1-(3S)-benzazepine-1-acetic acid hydrochloride ([14C]CGS 14824A)

International Nuclear Information System (INIS)

Chaudhuri, N.K.; Patera, R.; Markus, B.; Mingsang Sung

1987-01-01

The title compound, CGS 14824A, was synthesized with a 14 C-label in the azepine ring in 14 steps starting with 1-bromo-3-phenylpropane (1) and K 14 CN in an overall yield of 1.31%. The reaction of 1 with K 14 CN yielded the nitrile 2 which upon hydrolysis followed by ring closure gave α-tetralone-1- 14 C (4). Bromination of 4 followed by oxime formation gave the bromo oxime 5, which upon Beckmann rearrangement by acid treatment yielded the ring expansion product 6. The bromine atom of 6 was then replaced by an azido group, and an acetic ester side chain was introduced at the nitrogen atom. Catalytic reduction of the azido compound 8 gave a mixture of epimeric amino esters which was resolved by salt formation with L-tartaric acid. The negatively rotating isomer was then reacted with 4-phenyl-2-oxo-butanoate in presence of sodium cyanoborohydride to give a mixture of diastereoisomers which were separated as their benzyl esters by chromatography. The major isomer was then converted to labeled CGS 14824A. (author)

2-Amino-4-(4-bromophenyl-8-trifluoromethyl-3,4-dihydropyrimido[1,2-a][1,3,5]triazin-6(5H-onePart 13 in the series `Fused heterocyclic systems with an s-triazine ring'. For Part 12, see Dolzhenko et al. (2008b.

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Anton V. Dolzhenko

2009-04-01

Full Text Available The title compound, C13H9BrF3N5O, crystallizes with two independent molecules in the asymmetric unit. The pyrimidine rings of the molecules are planar [maximum deviations 0.053 (3 and 0.012 (3 Å], while the triazine rings adopt flattened half-boat conformations with the p-bromophenyl rings in the flagpole positions. The crystal packing is stabilized by a three-dimensional network of intermolecular N—H...N, N—H...O and N—H...F hydrogen bonds.

3-Benzyl-4-ethyl-1H-1,2,4-triazole-5(4H-thione

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Zbigniew Karczmarzyk

2013-02-01

Full Text Available The title compound, C11H13N3S, exists in the 5-thioxo tautomeric form. The benzene ring exhibits disorder with a refined ratio of 0.77 (2:0.23 (2 for components A and B with a common bridgehead C atom. The 1,2,4-triazole ring is essentially planar, with a maximum deviation of 0.002 (3 Å for the benzyl-substituted C atom, and forms dihedral angles of 88.94 (18 and 86.56 (49° with the benzene rings of components A and B, respectively. The angle between the plane of the ethyl chain and the mean plane of 1,2,4-triazole ring is 88.55 (15° and this conformation is stabilized by an intramolecular C—H...S contact. In the crystal, pairs of N—H...S hydrogen bonds link molecules into inversion dimers. π–π interactions are observed between the triazole and benzene rings, with centroid–centroid separations of 3.547 (4 and 3.544 (12 Å for components A and B, and slippages of 0.49 (6 and 0.58 (15 Å, respectively.

Dual RING E3 Architectures Regulate Multiubiquitination and Ubiquitin Chain Elongation by APC/C.

Science.gov (United States)

Brown, Nicholas G; VanderLinden, Ryan; Watson, Edmond R; Weissmann, Florian; Ordureau, Alban; Wu, Kuen-Phon; Zhang, Wei; Yu, Shanshan; Mercredi, Peter Y; Harrison, Joseph S; Davidson, Iain F; Qiao, Renping; Lu, Ying; Dube, Prakash; Brunner, Michael R; Grace, Christy R R; Miller, Darcie J; Haselbach, David; Jarvis, Marc A; Yamaguchi, Masaya; Yanishevski, David; Petzold, Georg; Sidhu, Sachdev S; Kuhlman, Brian; Kirschner, Marc W; Harper, J Wade; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

2016-06-02

Protein ubiquitination involves E1, E2, and E3 trienzyme cascades. E2 and RING E3 enzymes often collaborate to first prime a substrate with a single ubiquitin (UB) and then achieve different forms of polyubiquitination: multiubiquitination of several sites and elongation of linkage-specific UB chains. Here, cryo-EM and biochemistry show that the human E3 anaphase-promoting complex/cyclosome (APC/C) and its two partner E2s, UBE2C (aka UBCH10) and UBE2S, adopt specialized catalytic architectures for these two distinct forms of polyubiquitination. The APC/C RING constrains UBE2C proximal to a substrate and simultaneously binds a substrate-linked UB to drive processive multiubiquitination. Alternatively, during UB chain elongation, the RING does not bind UBE2S but rather lures an evolving substrate-linked UB to UBE2S positioned through a cullin interaction to generate a Lys11-linked chain. Our findings define mechanisms of APC/C regulation, and establish principles by which specialized E3-E2-substrate-UB architectures control different forms of polyubiquitination. Copyright © 2016 Elsevier Inc. All rights reserved.

Ethyl 2-[(5Z-5-(4-methylbenzylidene-2,4-dioxo-1,3-thiazolidin-3-yl]acetate

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Karrouchi Khalid

2016-06-01

Full Text Available In the title molecule, C15H15NO4S, the dihedral angle between the almost planar heterocyclic ring (r.m.s. deviation = 0.027 Å and the benzene ring is 5.33 (8°. The chain of the ester group adopts an extended conformation [C—O—C—C = −174.80 (14°]. In the crystal, inversion dimers linked by pairs of C—H...O hydrogen bonds generate R22(10 loops and further such bonds connect the dimers into `stair-step' chains propagating in [100].

1,4-Dimethyl-3-phenyl-3H-pyrazolo[3,4-c]isoquinolin-5(4H-one

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Giuseppe Daidone

2008-05-01

Full Text Available The title compound, C18H15N3O, is the product of the thermal decomposition of the diazonium salt derived from 2-amino-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-ylbenzamide. It is characterized by a trans orientation of the methyl groups with respect to the tricyclic ring system. The molecule has a nearly planar phenylpyrazolo[3,4-c]isoquinolin-5-one system, the largest deviation from the mean plane being 0.066 (2 Å for the O atom. The dihedral angle between the phenyl substituent and the heterotricycle is 67 (1°. The packing is stabilized by C—H...N hydrogen-bond interactions, with the formation of molecular chains along the c axis.

Crystal structure of 4-aminobenzoic acid–4-methylpyridine (1/1

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M. Krishna Kumar

2015-02-01

Full Text Available In the title 1:1 adduct, C6H7N·C7H7NO2, the carboxylic acid group is twisted at an angle of 4.32 (18° with respect to the attached benzene ring. In the crystal, the carboxylic acid group is linked to the pyridine ring by an O—H...N hydrogen bond, forming a dimer. The dimers are linked by N—H...O hydrogen bonds, generating (010 sheets.

Polymers Containing 1, 3, 4-Oxadiazole Rings for Advanced Materials

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Mariana-Dana Damaceanu

2011-10-01

Full Text Available This paper presents the synthesis, properties and potential applications of new polymers containing 1, 3, 4-oxadiazole rings, tacking into account the requirements of the modern technologies. Two classes of polymers containing oxadiazole rings were approached: polyamides and polyimides. All the polymers were characterized with respect to the identification of their chemical structure, solubility, molecular weights, film forming ability, thermal, dielectric and optical properties, and the behaviour of polyoxadiazole films upon irradiation with pulsed KrF laser. All the properties were discussed in correlation with their chemical structure and compared with those of related polymers.

Mineralization and volatilization of 14C-ring labelled 2,4-dichlorophenoxy acetic acid in Pakistani soils

International Nuclear Information System (INIS)

Hussain, Altaf; Iqbal, Zafar; Asi, Muhammad Rafique; Chaudhry, Jamil Anwar

2001-01-01

The mineralization and volatilization of [U-ring 14 C] 2,4-D in three Pakistani soils was investigated under laboratory conditions using 50 g of soil and uniform distribution of 1.345 μg/g of 2,4-D. Maximum losses of 14 CO 2 and volatile organic compounds occurred at day 7 and losses gradually slowed down after 21 days of incubation. The relative distribution of 14 C losses differed with soil type. Volatilization was higher in control soil as compared to test and treated soil in both the study seasons. The contribution of volatile material to the total loss in 1997 was highest in test soil (24.4%), and lowest in farm soil (19.8%) but in 1998 was highest in control soil (26%) and lowest in test and farm soils (7%) during 1998. (author)

(E-1-(2,4-Dimethylquinolin-3-yl-3-(4-methylphenylprop-2-en-1-one

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R. Prasath

2012-05-01

Full Text Available In the title compound, C21H19NO, there are two molecules in the asymmetric unit (Z′ = 2. There are π–π interactions between these two molecules [centroid–centroid distance = 3.678 (2 Å], as well as a weak C—H...O interaction. The conformation adopted by the two molecules is such that the quinoline mean plane and the benzene ring are almost perpendicular [89.04 (5 and 76.89 (4°]. In each molecule, the methyl group of the tolyl ring is disordered over two conformations, with occupancy ratios of 0.56 (3:0.44 (3 and 0.65 (3:0.35 (3.

1-Methylpiperazine-1,4-diium dipicrate

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Grzegorz Dutkiewicz

2011-02-01

Full Text Available In the crystal structure of the title compound [systematic name: 1-methylpiperazine-1,4-diium bis(2,4,6-trinitrophenolate], C5H14N22+·2C6H2N3O7−, the ionic components are connected by relatively strong N—H...O hydrogen bonds into centrosymmetric six-membered conglomerates, which comprise two dications and four anions. Besides Coulombic interactions, only weak C—H...O interactions and some stacking between picrates (separation between the planes of ca. 3.4 Å but only a small overlapping can be identified between these `building blocks' of the crystal structure. The piperazine ring adopts a chair conformation with the methyl substituent in the equatorial position. In the picrate anions, the twist angles of the nitro groups depend on their positions relative to the phenolate O atom: it is much smaller for the NO2 groups para to the C—O− group [15.23 (9and 3.92 (14°] than for the groups in the ortho positions [28.76 (13–39.84 (11°].

4-{(E-[2-(4-Iodobutoxybenzylidene]amino}-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H-one

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Hoong-Kun Fun

2010-07-01

Full Text Available The title Schiff base compound, C22H24IN3O2, adopts an E configuration about the central C=N bond. The pyrazolone ring makes a dihedral angle of 49.68 (10° with its attached phenyl ring. The phenolate plane makes dihedral angles of 16.78 (9 and 50.54 (9°, respectively, with the pyrazolone ring and the terminal phenyl ring. An intramolecular C—H...O hydrogen bond generates an S(6 ring motif. In the crystal structure, an intermolecular C—H...O hydrogen bond is also observed.

Study of 4H-SiC junction barrier Schottky diode using field guard ring termination

International Nuclear Information System (INIS)

Feng-Ping, Chen; Yu-Ming, Zhang; Hong-Liang, Lü; Yi-Men, Zhang; Jian-Hua, Huang

2010-01-01

This paper reports that the 4H-SiC Schottky barrier diode, PiN diode and junction barrier Schottky diode terminated by field guard rings are designed, fabricated and characterised. The measurements for forward and reverse characteristics have been done, and by comparison with each other, it shows that junction barrier Schottky diode has a lower reverse current density than that of the Schottky barrier diode and a higher forward drop than that of the PiN diode. High-temperature annealing is presented in this paper as well to figure out an optimised processing. The barrier height of 0.79 eV is formed with Ti in this work, the forward drop for the Schottky diode is 2.1 V, with an ideality factor of 3.2, and junction barrier Schottky diode with blocking voltage higher than 400 V was achieved by using field guard ring termination. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

New type of transformation of a 1,2,4-triazine ring to pyrazine derivatives

International Nuclear Information System (INIS)

Alekseev, S.G.; Charushin, V.N.; Chupakhin, O.N.

1987-01-01

We have discovered a new type of transformation of a triazine ring in which the l-ethyl-1,2,4-triazine cation participates. It has been established that the cation reacts at 20 0 C with ortho-phenylenediamine (in methylene chloride) and 5,6-diaminopyrimidin-4-one (in 9:1 ethanol-DMF) with the formation of quinoxaline (yield 43%) and pteridin-4-one (yield 23%). This transformation is based on the susceptibility of the cation to bi-addition of nucleophiles and proceeds via cyclic adducts which are then aromatized on account of separation of 3-morpholinoamidrazone. The reaction products were identified by comparison of their melting points and spectroscopic characteristics (NMR, mass-spectra) with those of samples whose structure is definitely known

SO(2,C) invariant ring structure of BRST cohomology and singular vectors in 2D gravity with C<1 matter

International Nuclear Information System (INIS)

Chair, N.; Dobrev, V.K.; Kanno, H.

1992-01-01

We consider BRST quantized 2D gravity coupled to conformal matter with arbitrary central change c M = c(p,q) M = 1 chiral ground ring. We show that the ring structure generated by the (relative BRST cohomology) discrete states in the (matter x Liouville x ghosts) Fock module may be obtained by this rotation. We give also explicit formulae for the discrete states. For some of them we use new formulae for c<1 Fock modules singular vectors which we present in terms of Schur polynomials generalizing the c = 1 expressions of Goldstone, while the rest of the discrete states we obtain by finding the proper SO(2,C) rotation. Our formulae give the extra physical states (arising from the relative BRST cohomology) on the boundaries of the p x q rectangles of the conformal lattice and thus all such states in (1,q) or (p,1) models. (author). 24 refs

4-Benzyloxy-1-oxaspiro[4.6]undec-3-en-2-one

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Jose H. Quintana Mendoza

2016-10-01

Full Text Available The title compound, C17H20O3, the cycloheptane ring adopts a slightly distorted chair conformation. The planar five-membered ring is inclined at 57.13 (11° to the phenyl ring of the benzyloxy substituent. In the crystal structure, C—H...O and C—H...π hydrogen bonds generate layers in the ac plane.

4,4-Dimethyl-3,4-dihydropyrido[2′,3′:3,4]pyrazolo[1,5-a][1,3,5]triazin-2-amine ethanol monosolvateFused heterocyclic systems with s-triazine ring. Part 16. for part 15, see Sachdeva et al. (2010.

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Lip Lin Koh

2011-01-01

Full Text Available In the title compound, C10H12N6·C2H5OH, the planarity of the heterocyclic system is slightly distorted at the triazine ring (r.m.s. deviation = 0.1191 Å, which adopts a conformation best described as intermediate between a flattened twisted boat and a half-boat with the tertiary Csp3 atom at the bow. In the crystal, molecules form centrosymmetric dimers connected by N...H—O and O...H—N hydrogen bonds between the amino group H atom, the ethanol solvent molecule and the triazine N atom, making an R44(12 graph-set motif. The other H atom of the amino group and the H atom on the endocyclic N atom form N...H—N hydrogen bonds with the N atoms of the pyrazole and pyridine rings, respectively, linking the molecules into C(7C(7 chains with the R22(8 binary graph-set motif running along [010].

Novel Platinum-Catalyzed Ring-Opening of 1,2-Cyclopropanated Sugars with Alcohols

DEFF Research Database (Denmark)

Beyer, Jürgen; Madsen, Robert

1998-01-01

Reaction of 1,2-cyclopropanated sugars with a catalytic amount ofZeise's dimer [Pt(C2H4)Cl2]2 and an alcohol gives 2-C-branched glycosides by a novel platinum catalyzed ring-opening. A wide variety of alcohols can participate in this ring-opening reaction giving 2-C-branched glycosides ranging from...

4-(2-Azaniumylethylpiperazin-1-ium bis(perchlorate

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Mohammad Reza Reisi

2011-09-01

Full Text Available In the title compound, C6H17N32+·2ClO4−, the piperazine ring adopts a chair conformation with the ethylammonium fragment occupying an equatorial position. In the crystal, the dications and perchlorate anions are linked through N—H...O hydrogen bonding and weak C—H...O hydrogen bonding into a three-dimensional supramolecular network.

1-(4,5-Dinitro-10-azatricyclo[6.3.1.02,7]dodeca-2,4,6-trien-10-yl-2,2,2-trifluoroethanone

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Jin-Tang Wang

2008-12-01

Full Text Available In the title compound, C13H10F3N3O5, a derivative of andrographolide, the five-membered ring adopts an envelope conformation, while the non-planar six-membered ring has a chair conformation. An intramolecular C—H...F hydrogen bond results in the formation of a non-planar six-membered ring adopting a twisted conformation. In the crystal structure, intermolecular C—H...O hydrogen bonds link the molecules into centrosymmetric dimers.

3-[4-(10H-Indolo[3,2-b]quinolin-11-ylpiperazin-1-yl]propan-1-ol

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Gary S. Nichol

2011-12-01

Full Text Available In the title compound, C22H24N4O, the aromatic moiety is essentially planar (r.m.s. deviation of a least-squares plane fitted through all non-H atoms = 0.0386 Å and is rotated by 89.98 (4° from the piperazine ring, which adopts the expected chair conformation. The propanol chain is not fully extended away from the piperazine ring. In the crystal, there are two unique hydrogen-bonding interactions. One is an O—H...N interaction which, together with an inversion-related symmetry equivalent, forms a ring motif. The second is an N—H...N interaction which links adjacent molecules by means of a chain motif which propagates in the c-axis direction. Overall, a two-dimensional hydrogen-bonded structure is formed.

2-(2-Chlorophenyl-2,3-dihydroquinazolin-4(1H-one

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Ming-Jian Li

2009-09-01

Full Text Available The title compound, C14H11ClN2O, was synthesized by the reaction of 2-chlorobenzaldehyde and 2-aminobenzamide in an ionic liquid. The pyrimidine ring adopts a skew-boat conformation and the two benzene rings make a dihedral angle of 87.1 (1°. In the crystal, N—H...O and C—H...N hydrogen bonding links the molecules along b.

Crystal structure of (1R,2S,4R,7R,8S,9R-3,3-dichloro-8,9-epoxy-4,8,12,12-tetramethyltricyclo[5.5.0.02,4]dodecane

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Ahmed Benzalim

2015-08-01

Full Text Available The title compound, C16H24Cl2O, is built up from two fused six- and seven-membered rings which bear a dichlorocyclopropane group and an epoxy group, respectively. In the molecule, the six-membered ring adopts an envelope configuration with the C atom linking the epoxy ring at the flap, while the seven-membered ring adopts a boat–sofa conformation.

rac-1-[6-Hydroxy-4-(4-methoxyphenyl-3,6-dimethyl-4,5,6,7-tetrahydro-2H-indazol-5-yl]ethanone

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Konstantin A. Potekhin

2013-02-01

Full Text Available The title compound, C18H22N2O3, represents a (4S,5R,6S-stereoisomer, crystallizing as a racemate in a centrosymmetric space group. The six-membered aliphatic ring adopts a half-chair conformation, with the hydroxy- and acetyl-substituted C atoms deviating by 0.458 (2 and −0.366 (2 Å, respectively, from the plane defined by other four ring atoms. The pyrazole ring is essentially planar [r.m.s deviation = 0.004 (2 Å]. In the crystal, the molecules are linked into chains along the b axis by N—H...N hydrogen bonds. The chains are linked by O—H...N hydrogen bonds into layers parallel to the bc plane.

(3R,4Z-1,3-Diethyl-4-(2-oxopropylidene-2,3,4,5-tetrahydro-1H-1,5-benzodiazepin-2-one

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Laila El Foujji

2018-04-01

Full Text Available In the title compound, C16H20N2O2, the seven-membered ring adopts a bowl-shaped conformation while the orientation of the 2-oxopropylidene substituent is determined by an intramolecular N—H...O hydrogen bond, which generates an S(6 ring. In the crystal, inversion dimers linked by pairs of very weak C—H...O interactions occur, which generate R22(8 loops.

N-(4-Fluorophenyl-2,6-dimethyl-1,3-dioxan-4-amine

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Gottimukkala Rambabu

2013-11-01

Full Text Available In the title compound, C12H16FNO2, the dioxane ring adopts a chair conformation with the methyl substituents and the C—N bond in equatorial orientations. Its mean plane subtends a dihedral angle of 40.17 (6° with the benzene ring. In the crystal, weak N—H...F hydrogen bonds link the molecules into C(7 chains propagating in [100].

3-Methylpyridinium 4-nitrobenzoate–4-nitrobenzoic acid (1/1

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P. Sivakumar

2016-06-01

Full Text Available In the title compound, C6H8N+·C7H4NO4−·C7H5NO4, the cation is protonated at its pyridine N atom and makes a dihedral angle of 74.14 (12° with the benzene ring of the anion. The benzene ring of the neutral molecule and the pyridine ring are inclined at an angle of 79.20 (12°. The two benzene rings form a dihedral angle of 6.00 (12° with each other. In the crystal, N—H...O, O—H...O and C—H...O hydrogen bonds link the cations, anions and neutral molecules to form layers parallel to the ac plane, which enlose R44(18 ring motifs. The layers are linked by further C—H...O hydrogen bonds and C—H...π interactions, forming a three-dimensional supramolecular architecture.

2-[1-(1-Naphthyl-1H-1,2,3-triazol-4-yl]pyridine

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Ulrich S. Schubert

2009-05-01

Full Text Available In the crystal structure of the title compound, C17H12N4, the angle between the naphthalene and 1H-1,2,3-triazole ring systems is 71.02 (4° and that between the pyridine and triazole rings is 8.30 (9°.

10a-Hydroxy-9-(4-methoxyphenyl-3,4,5,6,7,8a,9,10a-octahydro-1H-xanthene-1,8(2H-dione

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Hoong-Kun Fun

2012-08-01

Full Text Available In the title compound, C20H22O5, the tetrahydropyran, cyclohexene and cyclohexane rings of the xanthene ring system adopt half-chair, half-boat and chair conformations, respectively. The mean plane of the four roughly planar atoms of the tetrahydropyran ring (r.m.s. deviation = 0.111 Å forms a dihedral angle of 82.91 (4° with the methoxybenzene group. In the crystal, molecules are linked via O—H...O and C—H...O hydrogen bonds into sheets lying parallel to the ac plane. The crystal is further consolidated by weak C—H...π interactions.

N-(1-Acryloyl-2,2,6,6-tetramethylpiperidin-4-ylacrylamide

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Shailesh K. Goswami

2011-11-01

Full Text Available The title compound, C15H24N2O2, crystallizes with two unique molecules, (I and (II, in the asymmetric unit, differing in the orientation of the acryloyl units with respect to the piperidine rings. The acrylamide units are essentially planar in both molecules (r.m.s. deviations = 0.042 and 0.024 Å, respectively, as are the C3N chains of the acryloyl units. The carbonyl O atoms of the acryloyl systems lie significantly out of these planes, viz. by −0.171 (9 Å for molecule (I and by 0.33 (1 Å for molecule (II. The acrylamide and acryloyl planes are inclined at 68.7 (4° and 59.8 (3° in the two molecules. The piperidine rings each adopt twist boat conformations. In the crystal, strong N—H...O hydrogen bonds link the molecules into zigzag C(4 chains along b. Additional C—H...O contacts result in the formation of stacks along a.

Crystal structure of 2′-[(2′,4′-difluorobiphenyl-4-ylcarbonyl]-1′-phenyl-1′,2′,5′,6′,7′,7a'-hexahydrospiro[indole-3,3′-pyrrolizin]-2(1H-one

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M. Fathimunnisa

2015-08-01

Full Text Available In the title pyrrolizidine derivative, C33H26F2N2O2, both pyrrolidine rings of the pyrrolizidine moiety adopt an envelope conformation. The difluorophenyl group is oriented at an angle of 54.3 (1° with respect to the oxindole moiety. The crystal packing features an N—H...O hydrogen bond, which forms an R22(8 motif, and a C—H...O interaction, which generates a C(8 chain along [010]. In addition, this chain structure is stabilized by C—H...π interactions. In one of the pyrrolidine rings, the methylene group forming the flap of an envelope and the H atoms of the adjacent methylene groups are disordered over two sets of sites, with site-occupancy factors of 0.571 (4 and 0.429 (4

4-(1,3-Diphenyl-4,5-dihydro-1H-pyrazol-5-yl-1,3-diphenyl-1H-pyrazole

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Hoong-Kun Fun

2011-11-01

Full Text Available The title compound, C30H24N4, contains two pyrazole rings and four phenyl rings. The pyrazole rings are essentially planar, with maximum deviations of 0.003 (1 and 0.066 (1 Å and make a dihedral angle of 73.43 (6°. The two pyrazole rings make dihedral angles of 40.08 (6, 9.28 (6, 15.78 (8 and 17.25 (7° with their attached phenyl rings. In the crystal, there are no significant intermolecular hydrogen-bonding interactions. The crystal structure is stabilized by C—H...π interactions.

1,2,3,3-Tetramethyl-7-nitro-3,4-dihydroisoquinolinium tetrafluoroborate

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Mouna Bouzid

2016-04-01

Full Text Available The title salt, C13H17N2O2+·BF4−, was prepared by the methylation of the imine with Meerwein salt in dichloromethane. The asymmetric unit comprises a 1,3,3-trimethyl-7-nitro-3,4-dihydroisoquinolinium cation and a tetrafluoroborate anion. The coordination around the boron atom in the tetrafluoroborate anion is tetrahedral. The heterocyclic ring adopts a half-chair conformation. The crystal packing is governed by means of C—H...F contacts, which lead to the formation of a three-dimensional network.

Synthesis, NMR spectral and antimicrobial studies of some [N-methyl-3t-alkyl-2r,6c-diarylpiperidin-4-ylidine]-5‧-methylthiazolidine-4-ones

Science.gov (United States)

Prakash, S. M.; Pandiarajan, K.; Kumar, S.

2013-06-01

Four new [N-methyl-3t-alkyl-2r,6c-diaryl-4-ylidine]-5'-methylthiozolidin-4-ones 9-12 have been synthesized by the condensation of N-methyl-3t-alkyl-2r,6c-diarylpiperidin-4-one thiosemicarbazones with ethyl 2-bromopropionate. These compounds have been characterized using FT-IR, 1H NMR, 13C NMR spectral techniques. HOMOCOSY, HSQC and HMBC spectral study have been done for [N-methyl-3,3-dimethyl-2r,6c-bis(p-methoxyphenyl)piperidin-4-ylidine]-5'-methylthiazolidine-4-one (12). Two geometrical isomers are formed in this reaction. In all these compounds piperidin rings adopt chair conformation. The rotation of the aryl group at C-2 is rather slow in 10-12. Antimicrobial activities have also been studied for 9-12. These compounds are active against all the tested bacterial and fungal strains.

8-{(E-[(4-Chlorophenylimino]methyl}-1,1,7,7-tetramethyl-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-ol

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Esen Nur Kantar

2013-06-01

Full Text Available The title Schiff base, C23H27ClN2O adopts the phenol–imine tautomeric form, with an intramolecular O—H...N hydrogen bond, which generates an S(6 ring motif. Three C atoms of the heterocyclic moiety of the hexahydropyridoquinoline unit, as well as the two methyl groups bonded to one of these C atoms, are disordered over two set of sites, with anoccupancy ratio of 0.740 (4:0.260 (4.

Synthesis and structural characterization of (H4APPIP)[V3(C2O4)2(HPO4)3(PO4)(H2O)]·6H2O (APPIP=1,4-bis(3-aminopropyl)piperazine), a layered vanadium oxalatophosphate containing double 6-ring units

International Nuclear Information System (INIS)

Tang, M.-F.; Lii, K.-H.

2004-01-01

A new vanadium(III) oxalatophosphate has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction and thermogravimetric analysis. It crystallizes in the triclinic space group P1-bar with a=11.604(2) A, b=12.391(2) A, c=15.220(3) A, α=71.090(3) deg., β=82.630(3) deg., γ=62.979(3) deg., V=1843.8(5) A 3 and Z=2. The structure consists of V 6 (HPO 4 ) 6 double 6-ring (D6R) units connected by coordinating C 2 O 4 2- and PO 4 3- anions to form anionic sheets in the ab plane with charge-compensating quadruply protonated 1,4-bis(3-aminopropyl)piperazinium cations and water molecules between the sheets. It is one of the few compounds with 2D layer structures and the second example containing D6R units in the system of metal oxalatophosphates. The iron analogue was also synthesized

Dipropyl 3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine-1,2-dicarboxylate.

Science.gov (United States)

Rao, Guo-Wu; Hu, Wei-Xiao

2003-05-01

The title compound, C(22)H(24)N(4)O(4), was prepared from propyl chloroformate and 3,6-diphenyl-1,2-dihydro-s-tetrazine. This reaction yields the title compound rather than dipropyl 3,6-diphenyl-1,4-dihydro-s-tetrazine-1,4-dicarboxylate. The 2,3-diazabutadiene group in the central six-membered ring is not planar; the C=N double-bond length is 1.285 (2) A, and the average N-N single-bond length is 1.401 (3) A, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie +/- 0.3268 (17) A from the plane of the ring. The molecule has twofold crystallographic symmetry.

2-[(2,4,4,6,6-Pentachloro-1,3,5,2λ5,4λ5,6λ5-triazatriphosphinin-2-ylazanidyl]pyridinium

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Safaa A. Ahmed

2012-02-01

Full Text Available The title compound, C5H5Cl5N5P3, crystallizes as a zwitterion in which the pyridine N atom is protonated. An S(6 ring motif is formed via an intramolecular C—H...N hydrogen bond. The triazatriphosphinine ring adopts an envelope conformation, with one N atom displaced by 0.145 (1 Å from the other atoms. In the crystal, N—H...N and C—H...N hydrogen bonds link the molecules into centrosymmetric dimers containing one R22(7 ring motif and two R22(8 ring motifs.

Poly[dibromidobis[μ-1-(pyridin-4-ylmethyl-1H-1,2,4-triazole-κ2N:N′]cadmium

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Xiu-Zhi Xu

2011-02-01

Full Text Available The title coordination polymer, [CdBr2(C8H8N42]n, arose from a layer-separated diffusion synthesis at room temperature. The title compound is isotypic with the I and Cl analogues. The Cd atom, located on an inversion center, is coordinated by two bromide ions and four N atoms (two from triazole rings and two from pyridyl rings in a distorted trans-CdBr2N4 octahedral arrangement. The bridging 1-(4-pyridylmethyl-1H-1,2,4-triazole ligands are twisted [dihedral angle between the triazole and pyridine rings = 72.56 (13°], affording a two-dimensional 44 sheet structure in the crystal.

2-[(1R*,4R*-1,4-Dihydroxycyclohexyl]acetic acid

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Mohammad Arfan

2011-04-01

Full Text Available The title compound, C8H14O4, is an isolation product of the aerial parts of Senecio desfontanei. The acetic acid group is oriented at a dihedral angle of 48.03 (9° with respect to the basal plane of the cyclohexane-1,4-diol chair. An intramolecular O—H...O hydrogen bond generates an S(6 ring with an envelope conformation. In the crystal, molecules are linked by O—H...O hydrogen bonds, resulting in R33(20 ring motifs and C(2 O—H...O—H...O—H... chains. Overall, a three-dimensional polymeric network arises. A C—H...O contact is also present.

4-Aminobenzoic acid–4,4′-(propane-1,3-diyldipyridine (1/1

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Fwu Ming Shen

2010-11-01

Full Text Available In the crystal structure of the title compound, C13H14N2·C7H7NO2, the 4,4′-trimethylene-dipyridine (TMDP molecule displays an approximately planar structure, the maximum atomic deviation excluding H atoms being 0.118 (2 Å and the dihedral angle between the pyridine rings 4.59 (10°. The TMDP and 4-aminobenzoic acid (ABA molecules are linked by O—H...N and N—H...N hydrogen bonding, while ABA molecules are linked by O—H...O hydrogen bonding. C—H...π interactions are also observed between the methylene groups of TMDP molecules and the benzene rings of ABA molecules.

What is the mechanism of the OSO ring formation in sulfur tetroxide (SO4(C2v)) molecule?

Science.gov (United States)

Goodarzi, Moein; Vahedpour, Morteza; Solimannejad, Mohammad

2012-06-01

The mechanism of SO2 + O2 and O + SO3(D3h) reactions have been investigated at the MP2/6-31 + G(d) and CCSD(T)/cc-pV(Q + d)Z//MP2 levels on the triplet and singlet PESs. Although, no stable collision complexes have been found for the SO2 + O2(3∑g-), O(3P) + SO3(D3h) and O(1D) + SO3(D3h) reactions, 1IN(O2S-O2) has been considered on the singlet PES for the SO2 + O2(1Δg) reaction. The results show that there are no favorable paths for the OSO ring formation of SO4(C2v) in the atmospheric reactions of the SO2 + O2(3∑g-), SO2 + O2(1Δg) and O(3P) + SO3(D3h) while, the O(1D) + SO3(D3h) reaction can be suitable for the SO4(C2v) formation on the singlet PES.

endo-3,3-Dimethyl-4-oxobicyclo[3.1.0]hexan-2-yl methanesulfonate

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Adrian Kremer

2010-04-01

Full Text Available The relative configuration of the endo isomer of the title compound, C9H14O4S, has been established and the conformation of the diastereoisomer is discussed. The five-membered ring adopts an envelope conformation. The conformation of the methanesulfonate substituent is stabilized by intermolecular C—H...O hydrogen bonds. The crystal packing results in alternating layers of polar methanesulfonates and stacked bicyclohexanyl rings parallel to ab.

Arabidopsis C3HC4-RING finger E3 ubiquitin ligase AtAIRP4 positively regulates stress-responsive abscisic acid signaling.

Science.gov (United States)

Yang, Liang; Liu, Qiaohong; Liu, Zhibin; Yang, Hao; Wang, Jianmei; Li, Xufeng; Yang, Yi

2016-01-01

Degradation of proteins via the ubiquitin system is an important step in many stress signaling pathways in plants. E3 ligases recognize ligand proteins and dictate the high specificity of protein degradation, and thus, play a pivotal role in ubiquitination. Here, we identified a gene, named Arabidopsis thaliana abscisic acid (ABA)-insensitive RING protein 4 (AtAIRP4), which is induced by ABA and other stress treatments. AtAIRP4 encodes a cellular protein with a C3HC4-RING finger domain in its C-terminal side, which has in vitro E3 ligase activity. Loss of AtAIRP4 leads to a decrease in sensitivity of root elongation and stomatal closure to ABA, whereas overexpression of this gene in the T-DNA insertion mutant atairp4 effectively recovered the ABA-associated phenotypes. AtAIRP4 overexpression plants were hypersensitive to salt and osmotic stresses during seed germination, and showed drought avoidance compared with the wild-type and atairp4 mutant plants. In addition, the expression levels of ABA- and drought-induced marker genes in AtAIRP4 overexpression plants were markedly higher than those in the wild-type and atairp4 mutant plants. Hence, these results indicate that AtAIRP4 may act as a positive regulator of ABA-mediated drought avoidance and a negative regulator of salt tolerance in Arabidopsis. © 2015 The Authors. Journal of Integrative Plant Biology published by Wiley Publishing Asia Pty Ltd on behalf of Institute of Botany, Chinese Academy of Sciences.

(E-1-(1,3-Benzodioxol-5-yl-3-[4-(dimethylaminophenyl]prop-2-en-1-one

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Karthik Kumara

2017-01-01

Full Text Available In the title compound, C18H17NO3, the olefinic double bond adopts an E conformation. The molecule is nearly planar as indicated by the dihedral angle of 3.11 (6° between the benzodioxole and benzene rings. The carbonyl group lies in the plane of the olefinic double bond and the benzodioxole ring. The trans conformation of the C=C double bond in the central enone group is confirmed by the C=C—C—C torsion angle of −177.82 (14°.

2-Isobutyl-6-(4-methoxyphenylimidazo[2,1-b][1,3,4]thiadiazole

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Hoong-Kun Fun

2011-02-01

Full Text Available In the title compound, C15H17N3OS, the dihedral angle between the statistically planar imidazo[2,1-b][1,3,4]thiadiazole fused-ring system (r.m.s. deviation = 0.002 Å and the methyoxbenzene ring is 4.52 (6°. In the crystal, molecules are arranged into columns and stacked down the a axis. The crystal structure is stabilized by weak C—H...π and π–π interactions [centroid–centroid separations = 3.6053 (8 and 3.7088 (7 Å].

1,3-Diphenyl-3,4-dihydrobenzo[b][1,6]naphthyridine

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Werner Seebacher

2010-05-01

Full Text Available The title compound, C24H18N2, is the first structural example containing the 3,4-dihydrobenzo[b][1,6]naphthyridine fragment. It was synthesized from 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one and was crystallized from a methanol–ethanol solution over two years as a racemate. The C=N double bond [1.2868 (15 Å] is bent significantly out of the plane of the aromatic bicyclic ring system [N—C—C—C = −157.63 (12°] and out of the plane of the phenyl ring bonded at the 1-position [N—C—C—C = 41.15 (16°].

N,N′-Bis(2-hydroxy-3-ethoxybenzylidenebutane-1,4-diamine

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Hoong-Kun Fun

2009-04-01

Full Text Available The title Schiff base compound, C22H28N2O4, lies across a crystallographic inversion centre and adopts an E configuration with respect to the C=N bond. Pairs of weak intermolecular C—H...O interactions link neighbouring molecules into dimers with an R22(28 ring motif. The crystal structure is stabilized by intermolecular C—H...π interactions. An intramolecular O—H...N hydrogen bond occurs.

2-Aminobenzoic acid–4-(pyridin-4-yldisulfanylpyridine (1/1

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Hadi D. Arman

2011-12-01

Full Text Available The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanylpyridine molecule [dihedral angle between the pyridine rings = 89.06 (10°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O—H...N and N—H...N hydrogen bonds into a supramolecular chain along the b axis. These are connected into layers by π–π interactions occurring between pyridine rings [centroid–centroid distance = 3.8489 (15 Å]. The layers are connected along the a axis by C—H...O contacts. The crystal studied was a racemic twin.

1,4a-Dimethyl-6-methyl-ene-5-(5,5,6,6-tetra-cyano-2-methyl-cyclo-hex-2-enylmeth-yl)deca-hydro-naphthalene-1-carboxylic acid: a trans-communic acid derivative.

Science.gov (United States)

Rejouani, Nezha; Auhmani, Aziz; Ait Itto, My Youssef; Benharref, Ahmed; Daran, Jean-Claude

2008-01-18

In the search for cancer chemopreventive agents, we have studied the Diels-Alder reaction of trans-communic acid with tetra-cyano-ethyl-ene in the presence of SiO(2) as catalyst. The title cycloadduct, C(26)H(30)N(4)O(2), was obtained in 75% yield. The mol-ecules are arranged in pairs through O-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. Both the fused cyclohexyl rings adopt a chair conformation, whereas the nonfused ring adopts a half-chair conformation.

CESR-c Performance of a Wiggler-Dominated Storage Ring

CERN Document Server

Temnykh, Alexander

2005-01-01

CESR-c operates now as a Wiggler-Dominated Storage Ring extending the lowest operating energy to 1.5GeV/beam. To improve beam stability at low energy, 12 super-ferric wiggler magnets with total length of 15m and 2.1T maximum field were installed in the ring. They cause ~90% of total beam radiation lost and increase radiation damping rate by factor 10 from ~3 to 40 Hz. However, the field of the wiggler magnets not only initiates the radiation, but potentially affects beam dynamics. The latter was an issue of a great concern from the planning the CESR-c project. In this paper we describe general performance of CESR-c and report the results of an experimental study on some aspects of beam dynamics. Comparisons are made between the experimental data and the model prediction. We find that all parameters, which are critically dependent on wigglers, such as beam properties and ring nonlinearity, are in good agreement with those calculated from the model. This validates the ring and wiggler models and justifies our d...

Synthesis and Antibacterial Activities of Novel 2,5-Diphenylindolo[2,3-e] Pyrazolo[1',5':3",4"]pyrimido[2",1"-c] [1,2,4]triazines

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Mohamed G. Marei

2011-12-01

Full Text Available The formation of (E-3-{2-(2,5-diphenylpyrazolo[1,5-c]pyrimidin-7-ylhydrazono}indolin-2-ones 3 has been achieved by condensation of equimolar amounts of 7-hydrazino-2,5-diphenylpyrazolo[1,5-c]pyrimidine (1 and isatin (or isatin derivatives 2 at room temperature. The (E-products could be isomerized into corresponding the (Z-3 isomers. Reactions of the latter fused heterocyclic hydrazones towards different electro-philic reagents yielded the corresponding 3-substituted derivatives 4–7. Dehydrative cyclisation of the hydrazones 3 using phosphorus oxychloride afforded the 2,5-diphenyl- indolo[2,3-e]pyrazolo[1',5':3",4"]pyrimido[2",1"-c][1,2,4] triazines 13. The polyfused heterocyclic ring system 13 underwent electrophilic substitution reactions at position 4 rather than at position 3. The 3-bromo isomer of 17 was prepared by a sequence of reactions starting from 2,5-diphenylpyrazolo[1,5-c]pyrimidine-7(6H-thione (11. The orientation of the electrophilic attack was supported by spectroscopic and chemical evidence. Some of the synthesized compounds were found to possess slight to moderate activity against the microorganisms Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa.

N-(2-Chlorophenyl-2-({5-[4-(methylsulfanylbenzyl]-4-phenyl-4H-1,2,4-triazol-3-yl}sulfanylacetamide

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Hoong-Kun Fun

2011-08-01

Full Text Available In the title molecule, C24H21ClN4OS2, the central 1,2,4-triazole ring forms dihedral angles of 89.05 (9, 86.66 (9 and 82.70 (10° with the chloro-substituted benzene ring, the methylsulfanyl-substituted benzene ring and the phenyl ring, respectively. In the crystal, molecules are linked into sheets parallel to (100 by intermolecular N—H...N and weak C—H...O hydrogen bonds.

10-[1,1-Dichloro-4-(trimethylsilylbut-1-en-3-yn-2-yl]-10H-phenothiazine

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Satoru Umezono

2018-02-01

Full Text Available The title compound, C19H17Cl2NSSi, is an enamine derivative, in which the N atom adopts a shallow trigonal–pyramidal geometry [displacement from the plane of its attached C atoms = 0.1383 (18 Å]. The dihedral angle between the plane through the three amino carbon atoms and the vinyl group is 89.47 (7°. The phenothiazine unit has a butterfly structure and the central six-membered ring adopts a boat conformation. The fold angle between the benzene rings is 28.52 (7°. The crystal structure features weak Csp3—H...Cl hydrogen bonds, H...S contacts and π–π stacking interactions between phenothiazine units.

Crystal structures of (E-4-[1-(2-carbamothioylhydrazinylideneethyl]phenyl acetate and (E-4-[1-(2-carbamothioylhydrazinylideneethyl]phenyl benzoate

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Vijayan Viswanathan

2017-01-01

Full Text Available In the title compounds, C11H13N3O2S, (I, and C16H15N3O2S, (II, the thiosemicarbazone group adopts an extended conformation. The acetate ester (I crystallizes with two independent molecules in the asymmetric unit. In the benzoate ester (II, the planes of the two aryl rings are inclined to one another by 46.70 (7°. In both compounds, there is a short intramolecular N—H...N contact present, forming an S(5 ring motif. In the crystals of both compounds, molecules are linked via pairs of N—H...S hydrogen bonds, forming dimers with R22(8 ring motifs. The dimers are linked by N—H...S and N—H...O hydrogen bonds, forming slabs parallel to (01-1. In (I, there are N—H...π and C—H...π interactions present within the slabs, while in (II, there are only N—H...π interactions present.

(1S*,3R*,5S*,7S*-4,4,8,8-Tetrachloro-1-isopropyl-5-methyltricyclo[5.1.0.03,5]octane

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Koblandy M. Turdybekov

2014-04-01

Full Text Available The title compound, C12H16Cl4, is a derivative of the natural product 1-isopropyl-4-methylcyclohexa-1,4-diene, and represents a diastereomer with two trans-fused cyclopropane rings. Both enantiomers are present in the non-centrosymmetric polar space group Pna21. The central cyclohexane ring is planar within 0.02 (1 Å. The C atoms of dichloromethylene groups deviate from this plane by 1.19 (1 and −1.26 (1 Å, whereas the isopropyl and methyl groups are oriented more equatorially, deviating by 0.71 (1 and −0.87 (1 Å, respectively.

N-(2,6-Dimethyl-3-oxo-1-thia-4-azaspiro[4.5]dec-4-yl-2-hydroxy-2,2-diphenylacetamide

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Eser Ihan

2008-10-01

Full Text Available In the title compound, C24H28N2O3S, the pendant methyl C atom bonded to the cyclohexane ring is disordered over two sites in a 0.580 (11:0.420 (11 ratio. The cyclohexane ring adopts a distorted chair conformation while the thiazolidine ring has an envelope conformation. The two phenyl rings make a dihedral angle of 71.8 (2° with each other. The conformation is stabilized by an intramolecular N—H...O hydrogen bond. In the crystal structure, an intermolecular hydrogen bond O—H...O occurs.

6a-Nitro-6-(2,2,7,7-tetramethyltetrahydro-3aH-bis[1,3]dioxolo[4,5-b:4′,5′-d]pyran-5-yl-6a,6b,7,8,9,11a-hexahydro-6H-spiro[chromeno[3,4-a]pyrrolizine-11,11′-indeno[1,2-b]quinoxaline

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T. Anuradha

2014-01-01

Full Text Available In the title compound, C39H38N4O8, the quinoxaline and indene subunits are essentially planar, with maximum deviations of 0.071 (2 and 0.009 (2 Å, respectively. The indenoquinoxaline system forms a dihedral angle of 72.81 (3° with the chromenopyrrolizine system. The two dioxolane rings, as well as the pyran ring of the chromeno group and the terminal pyrrolizine, each adopt an envelope conformation with O and C as flap atoms. The central pyrrolizine ring adopts a twisted conformation. Intramolecular C—H...O and C—H...N hydrogen bonds occur. The crystal structure exhibits C—H...O hydrogen bonds, and is further stablized by C—H...π interactions, forming a two-dimensional network along the bc plane.

The crystal structure of 6-(4-chlorophenyl-2-(4-methylbenzylimidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde

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A. Sowmya

2016-10-01

Full Text Available In the title imidazo[2,1-b][1,3,4]thiadiazole derivative, C19H14ClN3OS, the 4-methylbenzyl and chlorophenyl rings are inclined to the planar imidazo[2,1-b][1,3,4]thiadiazole moiety (r.m.s. deviation = 0.012 Å by 64.5 (1 and 3.7 (1°, respectively. The molecular structure is primarily stabilized by a strong intramolecular C—H...O hydrogen bond, leading to the formation of a pseudo-seven-membered S(7 ring motif, and a short intramolecular C—H...N contact forming an S(5 ring motif. In the crystal, molecules are linked by pairs of C—H...S hydrogen bonds, forming inversion dimers. The dimers are linked by C—H...O and C—H...π interactions, forming chains propagating along [110].

Mineralization and volatilization of ring labelled 14C-2,4-D in three different soils

International Nuclear Information System (INIS)

Shrivastwa, M.; Singh, D.K.; Jindal, T.; Agarwal, H.C.

2001-01-01

Mineralization and volatilization of ring labelled 14 C-2,4-dichlorophenoxyacetic acid in soil was studied over a period of six weeks under laboratory conditions at 25 deg. C in three different soils collected from three sites, Delhi, Jaipur and Ludhiana. A very slow rate of both mineralization and volatilization was observed in all the three soils. The observed mineralization, was highest for the Delhi soil, 0.93%, followed by the Ludhiana soil, 0.73% and the Jaipur soil 0.14% in 42 days. The extent of volatilization was 0.46% for the Jaipur soil, 0.37% for the Ludhiana soil and 0.32% for the Delhi soil. (author)

Design of the 1.8 Tesla wiggler for the DAΦNE Main Rings

International Nuclear Information System (INIS)

Sanelli, C.; Hsieh, H.

1992-01-01

The electromagnetic and mechanical design of the eight wiggler magnets for DAΦNE Main Rings is described. The wigglers have a large 1.8 Tesla flat top magnetic field, 64 cm period and 4 cm gap. The magnetic 3-D calculations, the electromagnetic design and the adopted mechanical solutions, with particular attention to the vacuum chamber problems are described. A full scale prototype (5 full poles and two half pole) will be constructed in order to verify the accuracy of magnetic calculations, the end pole design and the multipole content. (author) 4 figs.; 1 tab

1-Methyl-1H-2,1-benzothiazin-4(3H-one 2,2-dioxide

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Muhammad Nadeem Arshad

2008-03-01

Full Text Available In the crystal structure of the title compound, C9H9NO3S, there is distorted tetrahedral geometry around the S atom. The sulfonyl group is almost normal to the benzene ring, while the carbonyl O atom and methyl C atom are on opposite sides of this ring. The heterocyclic ring adopts a half-boat conformation with the S atom out of the plane. The molecules are dimerized by hydrogen bonding involving the benzene ring and the sulfonyl group. These dimers are linked to each other in the same way. There is an intramolecular hydrogen bond between a methyl C—H group and a sulfonyl O atom, and a π–π interaction between the aromatic rings of two dimers at a centroid-to-centroid distance of 3.6373 (13 Å.

Synthesis, Structure, and Cyclocondensation of the 4,4,4-Trifluoro-3,3-dihydroxy-2-methyl-1-(thien-2-yl-1-butanone with Hydroxylamine and Hydrazine

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Alex F. C. Flores

2018-01-01

Full Text Available The synthesis of 4,4,4-trifluoro-3,3-dihydroxy-2-methyl-1-(thien-2-ylbutan-1-one (3 through acylation of 1,1-dimethoxy-1-(thien-2-ylpropane (1 with trifluoroacetic anhydride and its reactions with hydroxylamine and hydrazine was investigated. X-ray structural analysis of new trifluoromethyl-substituted dielectrophile 3 revealed that this hydrate exists as a racemate with inter- and intramolecular O-H·O bonds. The crystal structure shows alignment along axis b of pair molecules with the same configuration of the O2-H·O1 bond. For 5(3-trifluoromethyl-4-methyl-3(5-(thien-2-yl-1H-pyrazole (4, obtained via cyclocondensation of precursor 2 and hydrazine hydrochloride, X-ray structural analysis indicated that its rings are almost planar (torsion angle N2-C5-C6-C7–5.4° and that S1 at the thienyl moiety is anti-periplanar to N2 (torsion angle N2-C5-C6-S1 176.01; no disorder effect was observed for the thienyl ring.

3-(4-Fluorophenyl-1-[1′-(4-fluorophenyl-2-oxo-5′,6′,7′,7a′-tetrahydro-1H-indole-3(2H-spiro-3′(2′H-1H′-pyrrolizin-2′-yl]prop-2-en-1-one

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S. Sriman Narayanan

2008-09-01

Full Text Available In the title compound, C29H24F2N2O2, one of the pyrrolidine rings of the pyrrolizine system is disordered over two sites, with occupancy factors 0.734:0.266 (12. Both components of the disordered pyrrolidine ring adopt envelope conformations, whereas the other pyrrolidine ring adopts a twist conformation. The molecules are linked into centrosymmetric dimers by N—H...O hydrogen bonds and the dimers are connected via C—H...π interactions. The crystal structure is also stabilized by intermolecular C—H...F hydrogen bonds.

Azirinium ylides from α-diazoketones and 2H-azirines on the route to 2H-1,4-oxazines: three-membered ring opening vs 1,5-cyclization

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Nikolai V. Rostovskii

2015-03-01

Full Text Available Strained azirinium ylides derived from 2H-azirines and α-diazoketones under Rh(II-catalysis can undergo either irreversible ring opening across the N–C2 bond to 2-azabuta-1,3-dienes that further cyclize to 2H-1,4-oxazines or reversibly undergo a 1,5-cyclization to dihydroazireno[2,1-b]oxazoles. Dihydroazireno[2,1-b]oxazoles derived from 3-aryl-2H-azirines and 3-diazoacetylacetone or ethyl diazoacetoacetate are able to cycloadd to acetyl(methylketene generated from 3-diazoacetylacetone under Rh(II catalysis to give 4,6-dioxa-1-azabicyclo[3.2.1]oct-2-ene and/or 5,7-dioxa-1-azabicyclo[4.3.1]deca-3,8-diene-2-one derivatives. According to DFT calculations (B3LYP/6-31+G(d,p, the cycloaddition can involve two modes of nucleophilic attack of the dihydroazireno[2,1-b]oxazole intermediate on acetyl(methylketene followed by aziridine ring opening into atropoisomeric oxazolium betaines and cyclization. Azirinium ylides generated from 2,3-di- and 2,2,3-triaryl-substituted azirines give rise to only 2-azabuta-1,3-dienes and/or 2H-1,4-oxazines.

2-Methylsulfanyl-5,6-dihydro-2H-1,3-dithiolo[4,5-b][1,4]dioxin-2-ium tetrafluoroborate

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Guoquan Zhou

2012-04-01

Full Text Available The title compound, C6H7O2S3+·BF4−, consists of a planar 2-thioxo-1,3-dithiol-4,5-yl unit [maximum deviation from the ring plane = 0.020 (3 Å], with an ethylenedioxy group fused at the 4,5-positions; the ethylenedioxy C atoms are disordered over two positions with site-occupancy factors of 0.5. The 1,4-dioxine ring has a twist-chair conformation. Weak cation–anion S...F interactions [3.022 (4–3.095 (4 Å] and an S...O [3.247 (4 Å] interaction are present.

Crystal structure of 3-methyl-2,6-bis(4-methyl-1,3-thiazol-5-ylpiperidin-4-one

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A. Manimaran

2014-09-01

Full Text Available In the title compound, C14H17N3OS2, the central piperidinone ring adopts a chair conformation and the thiazole rings are inclined to its mean plane by 80.16 (12 and 67.15 (12°. The O atom and methyl group C atom deviate significantly from the mean plane of the central piperidinone ring, by 0.8138 (2 and 0.3175 (2 Å, respectively. The dihedral angle between the thiazole rings is 51.88 (13°. In the crystal, molecules are linked via C—H...O hydrogen bonds, forming zigzag C(10 chains running parallel to [001].

4-(3-Chlorophenyl-1-(3-chloropropylpiperazin-1-ium chloride redetermined at 100 K

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Muzzaffar Ahmad Bhat

2016-02-01

Full Text Available The crystal structure of the title salt, C13H19Cl2N2+·Cl−, has been reported previously [Homrighausen & Krause Bauer (2002. Acta Cryst. E58, o1395–o1396] based on room-temperature data, where it was found to contain a disordered chloropropyl group. We now present the structure at 100 K in which the chloropropyl group is ordered. The piperazine ring adopts a chair conformation with the exocyclic N—C bonds in equatorial orientations. The dihedral angle between the piperazine ring (all atoms and the benzene ring is 28.47 (5°. The chloropropyl group has an extended conformation [N—C—C—C = −177.25 (8 ° and C—C—C—Cl = 174.23 (7°]. In the crystal, charge-assisted N—H...Cl hydrogen bonds link the cation and anion into ion pairs. Numerous weak C—H...Cl interactions link the ion pairs into a three-dimensional network. Short Cl...Cl contacts [3.2419 (4 Å] are also observed.

Crystal structure of 1-{4-hydroxy-3-[(pyrrolidin-1-ylmethyl]phenyl}-3-phenylprop-2-en-1-one

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Abdullah Aydın

2016-05-01

Full Text Available In the title compound, C20H21NO2, the pyrrolidine ring adopts an envelope conformation with the N atom at the flap position. The central benzene ring makes dihedral angles of 21.39 (10 and 80.10 (15° with the phenyl ring and the mean plane of the pyrrolidine ring, respectively. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond, which closes an S(6 ring. A weak C—H...π interaction is observed in the crystal.

Benzo[4,5]cyclohepta[1,2-b]fluorene: an isomeric motif for pentacene containing linearly fused five-, six- and seven-membered rings

KAUST Repository

Yang, Xuejin

2016-06-07

Benzo[4,5]cyclohepta[1,2-b]fluorene (5a), a new π-conjugated polycyclic hydrocarbon containing linearly fused six-, five-, six-, seven- and six-membered rings (C6-C5-C6-C7-C6), was designed and its stable derivatives 5b and 5c were synthesized. With 22 π electrons, 5a is an isomer of pentacene with quinoidal, dipolar ionic and diradical resonance forms. Molecules 5b and 5c were experimentally investigated with cyclic voltammetry, electronic absorption spectroscopy and X-ray crystallographic analysis, and theoretically studied by calculating the NICS value, diradical character and dipole moment. A comparison of 5a–c with pentacene and other pentacene analogues containing linearly fused five- or seven- membered rings was also conducted and discussed. It was found that 5b behaved as a p-type organic semiconductor in solution-processed thin film transistors with field effect mobility of up to 0.025 cm2/Vs.

Benzo[4,5]cyclohepta[1,2-b]fluorene: an isomeric motif for pentacene containing linearly fused five-, six- and seven-membered rings

KAUST Repository

Yang, Xuejin; Shi, Xueliang; Aratani, Naoki; Goncalves, Theo; Huang, Kuo-Wei; Yamada, Hiroko; Chi, Chunyan; Miao, Qian

2016-01-01

Benzo[4,5]cyclohepta[1,2-b]fluorene (5a), a new π-conjugated polycyclic hydrocarbon containing linearly fused six-, five-, six-, seven- and six-membered rings (C6-C5-C6-C7-C6), was designed and its stable derivatives 5b and 5c were synthesized. With 22 π electrons, 5a is an isomer of pentacene with quinoidal, dipolar ionic and diradical resonance forms. Molecules 5b and 5c were experimentally investigated with cyclic voltammetry, electronic absorption spectroscopy and X-ray crystallographic analysis, and theoretically studied by calculating the NICS value, diradical character and dipole moment. A comparison of 5a–c with pentacene and other pentacene analogues containing linearly fused five- or seven- membered rings was also conducted and discussed. It was found that 5b behaved as a p-type organic semiconductor in solution-processed thin film transistors with field effect mobility of up to 0.025 cm2/Vs.

Prenatal Diagnosis of 4p and 4q Subtelomeric Microdeletion in De Novo Ring Chromosome 4

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Halit Akbas

2013-01-01

Full Text Available Ring chromosomes are unusual abnormalities that are observed in prenatal diagnosis. A 23-year-old patient (gravida 1, para 0 referred for amniocentesis due to abnormal maternal serum screening result in the 16th week of second pregnancy. Cytogenetic analysis of cultured amniyotic fluid cells revealed out ring chromosome 4. Both maternal and paternal karyotypes were normal. Terminal deletion was observed in both 4p and 4q arms of ring chromosome 4 by fluorescence in situ hybridization (FISH. However deletion was not observed in the WHS critical region of both normal and ring chromosome 4 by an additional FISH study. These results were confirmed by means of array-CGH showing terminal deletions on 4p16.3 (130 kb and 4q35.2 (2.449 Mb. In the 21th week of pregnancy, no gross anomalia, except two weeks symmetric growth retardation, was present in the fetal ultrasonographic examination. According to our review of literature, this is the first prenatal case with 4p and 4q subtelomeric deletion of ring chromosome 4 without the involvement of WHS critical region. Our report describes the prenatal case with a ring chromosome 4 abnormality completely characterized by array-CGH which provided complementary data for genetic counseling of prenatal diagnosis.

Prenatal diagnosis of 4p and 4q subtelomeric microdeletion in de novo ring chromosome 4.

Science.gov (United States)

Akbas, Halit; Cine, Naci; Erdemoglu, Mahmut; Atay, Ahmet Engin; Simsek, Selda; Turkyilmaz, Aysegul; Fidanboy, Mehmet

2013-01-01

Ring chromosomes are unusual abnormalities that are observed in prenatal diagnosis. A 23-year-old patient (gravida 1, para 0) referred for amniocentesis due to abnormal maternal serum screening result in the 16th week of second pregnancy. Cytogenetic analysis of cultured amniyotic fluid cells revealed out ring chromosome 4. Both maternal and paternal karyotypes were normal. Terminal deletion was observed in both 4p and 4q arms of ring chromosome 4 by fluorescence in situ hybridization (FISH). However deletion was not observed in the WHS critical region of both normal and ring chromosome 4 by an additional FISH study. These results were confirmed by means of array-CGH showing terminal deletions on 4p16.3 (130 kb) and 4q35.2 (2.449 Mb). In the 21th week of pregnancy, no gross anomalia, except two weeks symmetric growth retardation, was present in the fetal ultrasonographic examination. According to our review of literature, this is the first prenatal case with 4p and 4q subtelomeric deletion of ring chromosome 4 without the involvement of WHS critical region. Our report describes the prenatal case with a ring chromosome 4 abnormality completely characterized by array-CGH which provided complementary data for genetic counseling of prenatal diagnosis.

rac-Ethyl 2-hydroxy-2,7,7-trimethyl-4-(4-nitrophenyl-5-oxo-3,4,5,6,7,8-hexahydro-2H-chromene-3-carboxylate

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Konstantin A. Potekhin

2013-01-01

Full Text Available The title molecule, C21H25NO7, has four stereogenic centres and crystallized as a racemate. It consists of enantiomeric pairs with the relative configuration rac-(1R*,2S*,3R*. The cyclohexenone ring adopts an envelope conformation; the dimethyl-substituted C atom lies 0.640 (1 Å out of the mean plane formed by the rest of the ring atoms (r.m.s. deviation = 0.016 Å. The oxacyclohexene ring adopts a half-chair conformation, the hydroxy- and carboxyl-substituted C atoms lying −0.336 (1 and 0.419 (1 Å, respectively, out of the mean plane formed by the rest of the ring atoms (r.m.s. deviation = 0.002 Å. In the crystal, O—H...O hydrogen bonds link the molecules into a chain along the c-axis direction.

Ethyl 2-{3-[(2-chloro-1,3-thiazol-5-ylmethyl]-4-nitroimino-1,3,5-triazinan-1-yl}acetate

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Chuan-wen Sun

2010-06-01

Full Text Available In the title compound, C11H15ClN6O4S, which belongs to the neonicotinoid class of insecticidally active heterocyclic compounds, the six-membered triazine ring adopts an opened envolope conformation. The planar nitro imine group [dihedral angle between nitro and imine groups = 1.07 (7°] and the thiazole ring are oriented at a dihedral angle of 69.62 (8°. A classical intramolecular N—H...O hydrogen bond is found in the molecular structure. Moreover, one classical intermolecular N—H...N and four non-classical C—H...O and C—H...N hydrogen bonds are also present in the crystal structure. Besides intermolecular hydrogen bonds, the Cl atom forms an intermolecular short contact [3.020 (2 Å] with one of the nitro O atoms.

Performance of a C4F8O gas radiator ring imaging Cherenkov detector using multi-anode photomultiplier tubes

International Nuclear Information System (INIS)

Artuso, M.; Boulahouache, C.; Blusk, S.; Butt, J.; Dorjkhaidav, O.; Menaa, N.; Mountain, R.; Muramatsu, H.; Nandakumar, R.; Randrianarivony, K.; Sia, R.; Skwarnicki, T.; Stone, S.; Wang, J.C.; Zhang, K.

2006-01-01

We report on tests of a novel ring imaging Cherenkov (RICH) detection system consisting of a 3-m-long gaseous C 4 F 8 O radiator, a focusing mirror, and a photon detector array based on Hamamatsu multi-anode photomultiplier tubes. This system was developed to identify charged particles in the momentum range from 3 to 70GeV/c for the BTeV experiment

The effect of tempering on mechanical properties of 50Mn18Cr4WN retaining ring material

International Nuclear Information System (INIS)

Sun, M.C.; Guo, C.H.; Zheng, Z.Z.; Ma, Z.M.

1990-01-01

50Mn18Cr4WN is a retaining ring steel. It is strengthened by solution heat treatment and cold working. The process produces high macro residual stress. The retaining ring must be tempered for stress-relief. When the ring is sleeved, it is heated too. If the retaining ring is tempered, are the mechanical properties of the retaining ring damaged? The problem is described in the article. The tempering of testing pieces was carried out at several temperatures: 350degC, 400degC, 450degC, 500degC and 650degC. The tempering time was 3h. The yield point, tensile strength, elongation and reduction of area were determined by means of the tensile test. In the results, for temperatures between 350degC and 450degC, the yield point, tensile strength, elongation and reduction of area did not change notably. A stress corrosion cracking test was also carried out in a 3%Ni 4 NO 3 , 36%Ca(NO 3 ) 2 aqueous solution. K 1scc values after tempering at 450degC and without tempering were measured. The results showed that the K 1scc after tempering at 450degC decreased notably. Micrographs show that carbo-nitride precipitated. The precipitated carbo-nitride particles increased in size at the grain boundaries. The precipitated carbonitride particles increased in number at slip lines. It is clear that the precipitated particles lead to the increase of micro-cells and the micro-cells aggravated the stress corrosion cracking process. (orig.)

Methyl 2-(2,2-dimethyl-3a,6a-dihydrofuro[3,2-d][1,3]dioxol-5-yl-4-oxo-4H-chromene-3-carboxylate

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Devadasan Velmurugan

2013-08-01

Full Text Available In the title molecule, C18H16O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap. The furan ring is almost coplanar with the pyran ring, with a dihedral angle of 1.04 (10° between the planes, and it makes a dihedral angle of 67.97 (11° with the mean plane of the dioxolane ring. The latter makes a dihedral angle of 67.15 (10° with the pyran ring. The O atom attached to the pyran ring deviates by −0.009 (1 Å. The crystal packing features C—H...O hydrogen bonds, forming a three-dimensional structure. The methoxycarbonyl atoms are disordered over two positions, with a refined occupancy ratio of 0.508 (18:0.492 (18.

Crystal structure of 1-methoxy-5-methyl-N-phenyl-1,2,3-triazole-4-carboxamide

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Inna S. Khazhieva

2015-10-01

Full Text Available The title compound, C11H12N4O2,was prepared via the transformation of sodium 4-acetyl-1-phenyl-1H-[1.2.3]triazolate under the action of methoxyamine hydrochloride. The dihedral angle between the triazole and phenyl rings is 25.12 (16° and the C atom of the methoxy group deviates from the triazole plane by 0.894 (4Å. The conformation of the CONHR-group is consolodated by an intramolecular N—H...N hydrogen bond to an N-atom of the triazole ring, which closes an S(5 ring. In the crystal, weak N—H...N hydrogen bonds link the molecules into C(6 [010] chains.

Di-n-butyl 4,4′-dihydroxy-3,3′-{[(3aRS,7aRS-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene}dibenzoate

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Augusto Rivera

2011-09-01

Full Text Available The complete molecule of the title compound, C31H42N2O6, is generated by crystallographic twofold symmetry, with one C atom lying on the axis. The dihedral angle between the aromatic rings is 57.03 (6°. The central heterocyclic ring adopts a half-chair conformation. The molecular conformation is stabilized by two intramolecular O—H...N hydrogen bonds with the N atoms of the heterocyclic ring as the acceptors. In the crystal, molecules are linked into chains along the c axis by non-classical C—H...O hydrogen bonds.

Initial report on stress-corrosion-cracking experiments using Zircaloy-4 spent fuel cladding C-rings

International Nuclear Information System (INIS)

Smith, H.D.

1988-09-01

The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is sponsoring C-ring stress corrosion cracking scoping experiments as a first step in evaluating the potential for stress corrosion cracking of spent fuel cladding in a potential tuff repository environment. The objective is to scope the approximate behavior so that more precise pressurized tube testing can be performed over an appropriate range of stress, without expanding the long-term effort needlessly. The experiment consists of stressing, by compression with a dead weight load, C-rings fabricated from spent fuel cladding exposed to an environment of Well J-13 water held at 90/degree/C. The results indicate that stress corrosion cracking occurs at the high stress levels employed in the experiments. The cladding C-rings, tested at 90% of the stress at which elastic behavior is obtained in these specimens, broke in 25 to 64 d when tested in water. This was about one third of the time required for control tests to break in air. This is apparently the first observation of stress corrosion under the test conditions of relatively low temperature, benign environment but very high stress. The 150 ksi test stress could be applied as a result of the particular specimen geometry. By comparison, the uniaxial tensile yield stress is about 100 to 120 ksi and the ultimate stress is about 150 ksi. When a general model that fits the high stress results is extrapolated to lower stress levels, it indicates that the C-rings in experiments now running at /approximately/80% of the yield strength should take 200 to 225 d to break. 21 refs., 24 figs., 5 tabs

Heterocyclic Analogues of Xanthone and Xanthione. 1H-Pyrano[2,3-c:6,5-c]dipyrazol-4(7H-ones and Thiones: Synthesis and NMR Data

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Wolfgang Holzer

2010-09-01

Full Text Available The synthesis of the title compounds is described. Reaction of 1-substituted 2-pyrazolin-5-ones with 5-chloro-1-phenyl-1H-pyrazole-4-carbonyl chloride or 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbonyl chloride, respectively, using calcium hydroxide in refluxing 1,4-dioxane gave the corresponding 4-heteroaroylpyrazol-5-ols, which were cyclized into 1H-pyrano[2,3-c:6,5-c]dipyrazol-4(7H-ones by treatment with K2CO3/DMF. The latter were converted into the corresponding thiones upon reaction with Lawesson’s reagent. Detailed NMR spectroscopic investigations (1H, 13C, 15N of the ring systems and their precursors are presented.

Graphical linking of MO multicenter bond index and VB structures. II-5-c rings and 6-c heterocyclic rings

International Nuclear Information System (INIS)

Bollini, Carlos Guido; Giambiagi, Mario; Giambiagi, Myriam Segre de; Figueiredo, Aloysio Paiva de

2001-02-01

Through the graphical method proposed it is possible to set a link between an MO multicenter bond index and VB structures. The value of the index depends on the order of the atoms involved if they are more than three. For 5-c rings three basic structures are required; the eventually different values are 12. Unlike the 6-c case it may happen that different pairs of basic structures are used to build the same polygon. For the 6-c rings including heteroatoms the original degeneracy of benzene splits leading eventually to 60 different I ring values. (author)

Interaction Region Design for a Ring-Ring LHeC

CERN Document Server

Thompson, L N S; Bernard, N R; Fitterer, M; Holzer, B; Klein, M; Kostka, P

2011-01-01

tively low energy and moderately high intensity provides high luminosity TeV-scale e-p collisions at one of the LHC interaction points, running simultaneously with existing experiments. Two designs are studied; an electron ring situated in the LHC tunnel, and an electron linac. The focus of this paper is on the ring design. Designing an e-p machine presents interesting accelerator physics and design challenges, particularly when considering the interaction region. These include coupled optics, beam separation and unconventional mini-beta focusing schemes. Designs are constrained by an array of interdependent factors, including beam-beam interaction, detector dimensions and acceptance, luminosity and synchrotron radiation. Methods of addressing these complex issues are discussed. The current designs for the LHeC Ring-Ring interaction region and long straight section are presented and discussed, in the context of the project goals and design challenges encountered. Future developments and work are also discusse...

5-(4-Bromophenyl-2-(3,4-methylenedioxyphenyl-3-methylsulfanyl-1-benzofuran

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Hong Dae Choi

2009-10-01

Full Text Available The title compound, C22H15BrO3S, crystallizes with four molecules in the asymmetric unit. The 4-bromophenyl rings are rotated out of the benzofuran planes, with dihedral angles for the four molecules of 20.8 (2, 17.8 (2, 23.5 (4 and 23.9 (4°. The dihedral angles between the 3,4-methylenedioxyphenyl ring and the benzofuran plane are 13.5 (2, 7.1 (2, 18.6 (3 and 14.2 (3° in the four molecules. The crystal structure is stabilized by weak nonclassical intermolecular C—H...O hydrogen bonds. The crystal structure also exhibits intermolecular aromatic π–π interactions between the benzene and furan rings and between the 4-bromophenyl and 3,4-methylenedioxyphenyl rings from molecules of the same type; the centroid–centroid distances are 3.92 (1 and 3.79 (1, 3.91 (1, 3.77 (1 and 3.77 (1, and 3.79 (1 and 3.75 (1Å in the four molecules.

3-Methyl-4-(3-methylphenyl-5-(2-pyridyl-4H-1,2,4-triazole

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Dun-Ru Zhu

2009-05-01

Full Text Available In the molecule of the title compound, C15H14N4, the triazole ring is oriented at dihedral angles of 30.8 (2 and 67.4 (2° with respect to the pyridine and benzene rings, respectively. The crystal structure is stabilized by C—H...N hydrogen-bonding interactions, forming chains of molecules along [overline{1}01].

(4Z-1-Dodecyl-4-(2-oxopropylidene-2,3,4,5-tetrahydro-1H-1,5-benzodiazepin-2-one

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Jihad Sebhaoui

2016-11-01

Full Text Available In the title compound, C24H36N2O2, the orientation of the 2-oxopropylidene substituent is determined by the formation of an intramolecular N—H...O hydrogen bond. The benzodiazepine seven-membered ring adopts a slightly twisted boat conformation. The molecules pack in a bilayer fashion with the dodecyl chains intercalated to form the inner portion, and the benzodiazepine moieties on the outer surfaces.

2-[3-(4-Methoxyphenyl-1-phenyl-1H-pyrazol-5-yl]phenol

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available The title compound, C22H18N2O2, was derived from 1-(2-hydroxyphenyl-3-(4-methoxyphenylpropane-1,3-dione. The central pyrazole ring forms dihedral angles of 16.83 (5, 48.97 (4 and 51.68 (4°, respectively, with the methoxyphenyl, phenyl and hydroxyphenyl rings. The crystal packing is stabilized by O—H...N hydrogen bonding.

{2-[(4-Nitrobenzylideneamino]-4,5,6,7-tetrahydro-1-benzothiophen-3-yl}(phenylmethanone

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Manpreet Kaur

2014-06-01

Full Text Available In the title compound, C22H18N2O3S, disorder is found in the benzoyl group (A and B, as well as for four C atoms of the cyclohexene ring. Two orientations were modeled in a 0.583 (5:0.417 (5 ratio. The cyclohexene ring is in a distorted chair conformation. The dihedral angles between the mean plane of the thiophene ring and the 4-nitrobenzene and phenyl rings are 30.9 (8 and 64.8 (3 (A and 62.4 (7° (B. The mean planes of the 4-nitrobenzene and the phenyl rings are almost perpendicular to each other, with dihedral angles of 85.4 (1 (A and 83.9 (8° (B. An extensive array of weak C—H...O interactions consolidate molecules into a three-dimensional architecture, forming chains along [001] and [010] and layers parallel to (011.

Crystal structure of bis[4-(1H-pyrrol-1-ylphenyl] ferrocene-1,1′-dicarboxylate: a potential chemotherapeutic drug

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Wanda I. Pérez

2015-05-01

Full Text Available The title iron(II complex, [Fe(C16H12NO22], crystallizes in the orthorhombic space group Pbca with the Fe2+ cation positioned on an inversion center. The cyclopentadienyl (Cp rings adopt an anti conformation in contrast with other substituted ferrocenes in which the Cp rings appear in a nearly eclipsed conformation. The Cp and the aromatic rings are positioned out of the plane, with a twist angle of 70.20 (12°, and the C(Cp—C(CO bond length is shorter than a typical C—C single bond, which suggests a partial double-bond character and delocalization with the Cp π system. The structure of the complex is compared to other functionalized ferrocenes synthesized in our laboratory.

(E-4-(2,5-Dimethoxybenzylidene-2-phenyl-1,3-oxazol-5(4H-one

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Abdullah Mohamed Asiri

2009-08-01

Full Text Available The central azalactone ring in the title compound, C18H15NO4, is planar (r.m.s. deviation 0.05, 0.12 Å in both independent molecules comprising the asymmetric unit. The benzylidene substituent is coplanar with this ring [dihedral angle between the planes = 1.8 (1° in the first molecule and 2.8 (1° in the second], as is the phenyl substitutent [dihedral angle between rings = 4.6 (1 and 9.7 (1°, respectively].

Synthesis of ring-13C-labelled and ring-demethylated retinals

International Nuclear Information System (INIS)

Courtin, J.M.L.

1988-01-01

Efficient synthetic schemes are described for the preparation of the required mono- and di- 13 C labelled retinals based on simple 13 C labelled starting materials. Results from solid-state 13 C-NMR spectroscopic studies of the various ring- 13 C labelled bacteriorhodopsins and rhodopsins are discussed. 404 refs.; 74 figs.; 16 tabs

4-(4-Chlorophenyl-6-hydroxy-5-(2-thienylcarbonyl-6-(trifluoromethyl-3,4,5,6-tetrahydropyrimidin-2(1H-one monohydrate

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Mohammad Hossein Mosslemin

2009-06-01

Full Text Available The asymmetric unit of the title compound, C16H12ClF3N2O3S·H2O, contains two crystallographically independent organic molecules and two water molecules. The organic species are linked by an intermolecular O—H...O hydrogen bond, while the water molecules are connected to them through intermolecular O—H...N hydrogen bonds. The thiophene and phenyl rings are oriented at dihedral angles of 62.35 (4 in the first independent molecule and 60.74 (5° in the second, while the pyrimidine rings adopt twisted conformations in both molecules. Intramolecular N—H...F interactions result in the formation of two five-membered rings having envelope conformations. In the crystal structure, further intermolecular O—H...O and N—H...O hydrogen bonds link the molecules into chains.

Fuel element reactivity worth in different rings of the IPR-R1 TRIGA reactor

Energy Technology Data Exchange (ETDEWEB)

Gomes do Prado Souza, Rose Mary

2008-10-29

The thermal power of the IPR-R1 TRIGA Reactor will be upgraded from 100 kW to 250 kW. Starting core: loaded with 59 aluminum cladded fuel elements; 1.34 $ excess reactivity; and 100 kW power. It is planned to go 2.5 times the power licensed, i.e., 250 kW. This forces to enlarge the reactivity level. Nuclear reactors must have sufficient excess reactivity to compensate the negative reactivity feedback effects caused by: the fuel temperature, fuel burnup, fission poisoning production, and to allow full power operation for predetermined period of time. To provide information for the calculation of the new core arrangement, the reactivity worth of some fuel elements in the core were measured as well as the determination of the core reactivity increase in the substitution of the original fuels, cladded with aluminium, for new ones, cladded with stainless steel. The reactivity worth of fuel element was measured from the difference in critical position of the control rods, calibrated by the positive period method, before and after the fuel element was withdrawn from the core. The magnitude of reactivity increase was determined when withdrawing the original Al-clad fuel (a little burned up) and the graphite elements, and inserting a fresh Al-clad fuel element, one by one. Experimental results indicated that to obtain enough reactivity excess to increase the rector power the addition of 4 new fuel elements in the core would be sufficient: - Substitution of 4 Al-clad fuel elements in ring C for fresh stainless steel clad fuel elements; - increase the reactivity {approx_equal} 4 x 6.5 = 26 cents; - The removed 4 Al-clad F. E. (a little burned up) put in the core periphery, ring F, replacing graphite elements; - add < 4 x 39 156 cents (39 cents was measured with a fresh F.E.). Neutron source was changed from position F7 to F8. Control and Safety rods were moved from ring D to C in order to increase their reactivity worth. Regulating rod was kept at the same position, F16. Four

Methyl 11-hydroxy-9-[1-(4-methoxyphenyl-4-oxo-3-phenoxyazetidin-2-yl]-18-oxo-10-oxa-2-azapentacyclo[9.7.0.01,8.02,6.012,17]octadeca-12(17,13,15-triene-8-carboxylate

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S. Sundaramoorthy

2012-07-01

Full Text Available In the title compound, C34H32N2O8, one of the pyrrolidine rings in the pyrrolizidine ring system adopts a twist conformation, whereas the other ring adopts an envelope conformation (C atom as flap. The five-membered ring in the indene ring system and the fused furan ring also adopt envelope conformations (C and O atoms as flaps, respectively. The β-lactam ring makes dihedral angles of 23.41 (2 and 25.98 (2°, respectively, with the attached methoxyphenyl and phenoxy rings. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond, generating an S(5 motif. In the crystal, molecules are linked into C(12 chains running along the a axis by C—H...O hydrogen bonds. The structure is further consolidated by weak intermolecular C—H...π and π–π interactions [centroid–centroid distance = 3.7987 (14 Å].

Development of stress relaxation measurement by a small size C-ring specimen method

International Nuclear Information System (INIS)

Shimanuki, Shizuka; Nakata, Kiyotomo; Kasahara, Shigeki; Kuniya, Jiro

2002-01-01

A stress relaxation measurement method has been developed by using C-ring specimens, and a specimen size effect has been evaluated taking radiation-induced stress relaxation into consideration. C-ring specimens were stressed by forcing a wedge in the gap. Giving an appropriate eccentric configuration in the half of the ring opposite the gap, the stress gradient along the circumference was eliminated in the section and the stress level could be varied by changing the gap spacing. The validity of the C-ring test method was confirmed by thermally stress relaxation experiments at annealing temperatures from 300 to 600degC for 1 min to 200 h in carbon steel: considerable stress relaxation could be measured for all levels of applied stress even at relatively low annealing temperatures. The relaxation results obtained from the C-ring test were in good agreement with those from a uniaxial tensile stress relaxation test. The smaller C-ring specimen with about 40 mm diameter, which is required for radiation-induced stress relaxation test, also showed adequate accuracy on stress relaxation at 600 to 830degC in stainless steel, compared with the large size C-ring specimen test. (author)

3′,7′,7′-Trimethyl-1′-phenyl-5′,6′,7′,8′-tetrahydrospiro[indoline-3,4′-(1H,4H-pyrazolo[3,4-b]chromene]-2,5′-dione

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Li-Qin Zhao

2010-12-01

Full Text Available The title spirooxindole compound, C26H23N3O3, was prepared by the reaction of isatin, 3-methyl-1-phenyl-2-pyrazolin-5-one and 5,5-dimethylcyclohexane-1,3-dione in an ethanol solution. The fused cyclohexene ring adopts an envelope conformation. The dihedral angle between the aromatic and pyrazoline rings is 23.70 (8°. An intramolecular C—H...O interaction occurs. The crystal structure is stabilized by N—H...N hydrogen-bonding interactions, leading to a zigzag chain along the b axis.

2-Aminobenzoic acid–4-(pyridin-4-yldisulfanyl)pyridine (1/1)

OpenAIRE

Hadi D. Arman; Trupta Kaulgud; Edward R. T. Tiekink

2011-01-01

The title 1:1 co-crystal, C7H7NO2·C10H8N2S2, features a highly twisted 4-(pyridin-4-yldisulfanyl)pyridine molecule [dihedral angle between the pyridine rings = 89.06 (10)°]. A small twist is evident in the 2-aminobenzoic acid molecule, with the C—C—C—O torsion angle being −7.7 (3)°. An N—H...O hydrogen bond occurs in the 2-aminobenzoic acid molecule. In the crystal, molecules are linked by O&#...

Synthesis of 2-arylidenebenzocycloalkanones containing N-donor heterocyclic rings

Energy Technology Data Exchange (ETDEWEB)

Sun, S.-W., E-mail: sunsw0819@163.com [Yuncheng University, Department of Applied Chemistry (China); Zhang, X., E-mail: zhangx@hit.edu.cn [Harbin Institute of Technology, Academy of Fundamental and Interdisciplinary Science (China); Wang, G.-F. [Yuncheng University, Department of Applied Chemistry (China)

2016-12-15

A series of 2-arylidenebenzocycloalkanones containing heterocyclic rings 1–8 were prepared and characterized by IR, {sup 1}H NMR and elemental analyses. X-ray diffraction study of 6 reveals that the cyclohexyl ring of the 3,4-dihydronaphthalen-1(2H)-one adopts a chair conformation with a maximum deviation of 0.547(3) Å and makes dihedral angles of 52.24(17)° and 11.23(16)°, respectively, with the benzene plane and the mean plane of the benzimidazole ring.

2-Hydroxy-16-[(E-4-methylbenzylidene]-13-(4-methylphenyl-12-phenyl-1,11-diazapentacyclo[12.3.1.02,10.03,8.010,14]octadeca-3(8,4,6-triene-9,15-dione

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Raju Suresh Kumar

2010-08-01

Full Text Available In the title compound, C37H32N2O3, an intramolecular O—H...N hydrogen bond generates a five-membered ring, producing an S(5 motif. The piperidone ring adopts a half-chair conformation. The two fused pyrrolidine rings have similar envelope conformations. The interplanar angles between the benzene rings A/B and C/D are 75.68 (7 and 30.22 (6°, respectively. In the crystal structure, adjacent molecules are interconnected into chains propagating along the [010] direction via intermolecular C—H...O hydrogen bonds. Further stabilization is provided by weak C—H...π interactions.

4,4′-Diiodo-2,2′-[(3aR,7aR-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diylbis(methylene]diphenol

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Augusto Rivera

2011-09-01

Full Text Available In the crystal structure of the title compound, C21H24I2N2O2, the two N atoms of the imidazolidine moiety are linked to the hydroxy groups by intramolecular O—H...N hydrogen-bonding interactions. The cyclohexane ring adopts a chair conformation and the heterocyclic ring to which it is fused has a twisted envelope conformation.

Crystal structures and conformations of two Diels–Alder adduct derivatives: 1,8-bis(thiophen-2-yl-14-oxatetracyclo[6.5.1.02,7.09,13]tetradeca-2(7,3,5-trien-10-one and 1,8-diphenyl-14-oxatetracyclo[6.5.1.02,7.09,13] tetradeca-2,4,6-trien-10-one

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S. Gopinath

2015-02-01

Full Text Available The title compounds, C21H16O2S2 (I and C25H20O2 (II, are products of a tandem `pincer' Diels–Alder reaction consisting of [2 + 2] cycloadditions between benzo[c]furan and cyclopentanone. Each comprises a fused tetracyclic ring system containing two five-membered rings (in envelope conformations with the O atom as the flap and six-membered rings (in boat conformations. In addition, two thiophene rings in (I and two phenyl rings in (II are attached to the tetracyclic ring system. The cyclopentanone ring adopts a twisted conformation in (I and an envelope conformation in (II. In (I, the thiophene rings are positionally disordered over two sets of sites, with occupancy ratios of 0.901 (2:0.099 (2 and 0.666 (2:0.334 (2. In (II, the oxygen atom of the cyclopentanone ring is rotationally disordered over two sites with an occupancy ratio of 0.579 (4:0.421 (4. The molecular structure of (I is stabilized by an intramolecular C—H...O hydrogen bond, which generates an S(7 ring motif. In the crystal, the molecules are linked via weak C—H...O hydrogen bonds, which generate R22(16 ring motifs in (I and C(8 chains in (II. In both structures, the crystal packing also features C—H...π interactions. The crystal studied of compound (I was twinned by non-merohedry. The twin component is related by the twin law [−1 0 0 −0.101 1 −0.484 0 0 −1] operated by a twofold rotation axis parallel to the b axis. The structure of (I was refined with a twin scale factor of 0.275 (2.

Observation of e+e-→ϕ χc 1 and ϕ χc 2 at √{s }=4.600 GeV

Science.gov (United States)

Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chai, J.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, P. L.; Chen, S. J.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; de Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fang, J.; Fang, S. S.; Fang, Y.; Farinelli, R.; Fava, L.; Fegan, S.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guo, A. Q.; Guo, R. P.; Guo, Y. P.; Haddadi, Z.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, X. Q.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, H. M.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin, Y.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Khan, T.; Khoukaz, A.; Kiese, P.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuemmel, M.; Kuessner, M.; Kuhlmann, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leithoff, H.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K. J.; Li, Kang; Li, Ke; Li, Lei; Li, P. L.; Li, P. R.; Li, Q. Y.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. M.; Liu, Huanhuan; Liu, Huihui; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, Ke; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Musiol, P.; Mustafa, A.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.; Patteri, P.; Pelizaeus, M.; Pellegrino, J.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Pitka, A.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Richter, M.; Ripka, M.; Rolo, M.; Rong, G.; Rosner, Ch.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Song, J. J.; Song, W. M.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Tapan, I.; Tiemens, M.; Tsednee, B.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, Dan; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, Meng; Wang, P.; Wang, P. L.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wang, Zongyuan; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Y. J.; Xiao, Z. J.; Xie, Y. G.; Xie, Y. H.; Xiong, X. A.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. H.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y. H.; Zhang, Y. T.; Zhang, Yang; Zhang, Yao; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhou, Y. X.; Zhu, J.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Besiii Collaboration

2018-02-01

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of √{s }=4.600 GeV , we search for the production of e+e-→ϕ χc 0 ,1 ,2 . A search is also performed for the charmonium-like state X (4140 ) in the radiative transition e+e-→γ X (4140 ) with X (4140 ) subsequently decaying into ϕ J /ψ . The processes e+e-→ϕ χc 1 and ϕ χc 2 are observed for the first time, each with a statistical significance of more than 10 σ , and the Born cross sections are measured to be (4. 2-1.0+1.7±0.3 ) and (6. 7-1.7+3.4±0.5 ) pb , respectively, where the first uncertainties are statistical and the second systematic. No significant signals are observed for e+e-→ϕ χc 0 and e+e-→γ X (4140 ) and upper limits on the Born cross sections at 90% C.L. are provided at √{s }=4.600 GeV .

6-Methoxy-2-phenyl-4,4a,6,7,8,8a-hexahydro-2H-pyrano[3,2-d][1,3]dioxine-7,8-diyl bis(4-methylbenzene-1-sulfonate

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James L. Wardell

2012-03-01

Full Text Available In the title α-D-glucopyranoside derivative, C28H30O10S2, each heterocyclic ring adopts a chair conformation. In the trisubstituted ring, the methoxy and one sulfonate group occupy axial positions, whereas the second sulfonate group occupies an axial position. The phenyl group on the other ring is in an equatorial position. In the crystal, supramolecular chains propagating along [100] are formed through C—H...O and C—H...π interactions.

3-[(E-(4-Chlorobenzylideneamino]-1-phenylthiourea

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Nur Nadia Dzulkifli

2011-04-01

Full Text Available In the title compound, C14H12ClN3S, the dihedral angle between the terminal benzene rings is 56.6 (2°; the benzene rings lie to the same side of the molecule. The major twist in the molecule occurs around the Car—N bond (ar is aromatic [C—N—C—C = 49.9 (5°]. The configuration about the N=C bond [1.271 (4 Å] is E. The amine H atoms lie on opposite sides of the molecule with one forming an intramolecular N—H...N(imine hydrogen bond and an S(5 ring. In the crystal, centrosymmetric dimers are formed via {...HNC=S}2 synthons.

4,4′-(Propane-1,3-diyldioxydibenzaldehyde

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Qamar Ali

2010-07-01

Full Text Available The title compound, C17H16O4, is a dialdehyde in which two formylphenoxy units are linked by a –CH2CH2CH2– chain; the molecule is V-shaped with the middle methylene C atom as the apex. The two benzene rings are aligned at 77.4 (1°. In the crystal, molecules are linked into centrosymmetric dimers by pairs of non-classical C—H...O hydrogen bonds.

Deconvolution of the tree ring based delta13C record

International Nuclear Information System (INIS)

Peng, T.; Broecker, W.S.; Freyer, H.D.; Trumbore, S.

1983-01-01

We assumed that the tree-ring based 13 C/ 12 C record constructed by Freyer and Belacy (1983) to be representative of the fossil fuel and forest-soil induced 13 C/ 12 C change for atmospheric CO 2 . Through the use of a modification of the Oeschger et al. ocean model, we have computed the contribution of the combustion of coal, oil, and natural gas to this observed 13 C/ 12 C change. A large residual remains when the tree-ring-based record is corrected for the contribution of fossil fuel CO 2 . A deconvolution was performed on this residual to determine the time history and magnitude of the forest-soil reservoir changes over the past 150 years. Several important conclusions were reached. (1) The magnitude of the integrated CO 2 input from these sources was about 1.6 times that from fossil fuels. (2) The forest-soil contribution reached a broad maximum centered at about 1900. (3) Over the 2 decade period covered by the Mauna Loa atmospheric CO 2 content record, the input from forests and soils was about 30% that from fossil fuels. (4) The 13 C/ 12 C trend over the last 20 years was dominated by the input of fossil fuel CO 2 . (5) The forest-soil release did not contribute significantly to the secular increase in atmospheric CO 2 observed over the last 20 years. (6) The pre-1850 atmospheric p2 values must have been in the range 245 to 270 x 10 -6 atmospheres

Uptake, translocation, and distribution of root-applied [C ring-U-14C]-ZJ0273 in plants of oilseed rape and rice

International Nuclear Information System (INIS)

Li Zheng; Han Ailiang; Zhang Yanfei; Li Juying; Wang Yue; Wang Haiyan; Ye Qingfu; Lu Long

2009-01-01

ZJ0273, propyl 4-(2-(4, 6-dimethoxypyrimidin-2-yloxy) benzylamino) benzoate, is a novel ALS-inhibited herbicide development for pre-and post-emergence weed control in field of oilseed rape. The comparative uptake, translocation and distribution of root-applied [C ring-U- 14 C] ZJ0273 in the plants of susceptible rice and tolerant oilseed rape were investigated under laboratory conditions. The results showed that the uptake of [C ring-U- 14 C]-ZJ0273 in both rice (Oryza sativa L.) and oilseed rape (Brassica napus L.) increased with time. Larger percentage of the applied ZJ0273 was uptaken by rice than oilseed rape at any sampling time. At 384 hours after treatment, the uptake of [C ring-U- 14 C]-ZJ0273 reached 24.1% of the applied amount in rice, while only 4.1% of the applied in oilseed rape. The majority of the absorbed ZJ0273 remained in the root of the tested plants, which indicated the weak mobility of ZJ0273 and/or its metabolites in both the plants of susceptible rice and tolerant oilseed rape. The radioactivity per unit of dry weight in the roots and leaves of rice was 9.470 Bq/mg and 0.910 Bq/mg, respectively, which was significantly higher than that in oilseed rape (3.870 Bq/mg and 0.390 Bq/mg). Therefore, the difference in the total uptake of ZJ0273 and the accumulation of ZJ0273 and/or its metabolites perunit of dry weight between rice and oilseed rape, which revealed in this study, might be one of the reasons for the different susceptibility of rice and oilseed rape on ZJ0273. (authors)

C20H4(C4F8)3: a fluorine-containing annulated corannulene that is a better electron acceptor than C60.

Science.gov (United States)

Kuvychko, Igor V; Dubceac, Cristina; Deng, Shihu H M; Wang, Xue-Bin; Granovsky, Alexander A; Popov, Alexey A; Petrukhina, Marina A; Strauss, Steven H; Boltalina, Olga V

2013-07-15

At sixes and sevens: The reaction of corannulene with 35 equivalents of 1,4-C4F8I2 is an efficient and a relatively selective process that yields two main products in which six H atoms are substituted with three C4F8 moieties that form six- and seven-membered rings. Low-temperature photoelectron spectroscopy showed the electron affinity of the major isomer (shown) exceeds that of C60 (2.74±0.02 and 2.689±0.008 eV, respectively). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

4-twist helix snake to maintain polarization in multi-GeV proton rings

Science.gov (United States)

Antoulinakis, F.; Chen, Y.; Dutton, A.; Rossi De La Fuente, E.; Haupert, S.; Ljungman, E. A.; Myers, P. D.; Thompson, J. K.; Tai, A.; Aidala, C. A.; Courant, E. D.; Krisch, A. D.; Leonova, M. A.; Lorenzon, W.; Raymond, R. S.; Sivers, D. W.; Wong, V. K.; Yang, T.; Derbenev, Y. S.; Morozov, V. S.; Kondratenko, A. M.

2017-09-01

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven's 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab's 120 GeV /c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9 - 120 GeV /c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. This snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

4-twist helix snake to maintain polarization in multi-GeV proton rings

International Nuclear Information System (INIS)

Antoulinakis, F.; Chen, Y.; Dutton, A.; Rossi De La Fuente, E.; Haupert, S.

2017-01-01

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120 GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120 GeV/c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. Here, this snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

4-[(3-Hydroxyanilino(phenylmethylidene]-3-methyl-1-phenyl-1H-pyrazol-5(4H-one

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Keraghel Saida

2012-06-01

Full Text Available In the title compound, C23H19N3O2, the dihedral angles formed by the pyrazolone ring with the three benzene rings are 30.91 (6, 60.96 (4 and 57.01 (4°. The ligand is in the enamine–keto form and its structure is stabilized by an intramolecular N—H...O hydrogen bond. In the crystal, O—H...N hydrogen bonds link molecules into chains parallel to [01-1].

(1R,4R,6S,7R-5,5-Dibromo-1,4,8,8-tetramethyltricyclo[5.4.1.04,6]dodecan-12-one

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Mohamed Zaki

2014-05-01

Full Text Available The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene, which was isolated from Atlas cedar (Cedrus atlantica. The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring. In both molecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

(2RS)-2-(2,4-Difluoro-phen-yl)-1-[(4-iodo-benz-yl)(meth-yl)amino]-3-(1H-1,2,4-tri-azol-1-yl)propan-2-ol.

Science.gov (United States)

Xiong, Hui-Ping; Gao, Shou-Hong; Li, Chun-Tong; Wu, Zhi-Jun

2012-08-01

IN THE TITLE COMPOUND (COMMON NAME: iodiconazole), C(19)H(19)F(2)IN(4)O, there is an intra-molecular O-H⋯N hydrogen bond and mol-ecules are linked by weak inter-actions only, namely C-H⋯N, C-H⋯O and C-H⋯F hydrogen bonds, and π-electron ring-π-electron ring inter-actions between the triazole rings with centroid-centroid distances of 3.725 (3) Å.

Using Ring Strain to Control 4π-Electrocyclization Reactions: Torquoselectivity in Ring Closing of Medium-Ring Dienes and Ring Opening of Bicyclic Cyclobutenes.

Science.gov (United States)

Boon, Byron A; Green, Aaron G; Liu, Peng; Houk, K N; Merlic, Craig A

2017-05-05

Syntheses of strained cyclic dienes were accomplished via palladium(II)-catalyzed oxidative cyclizations of terminal bis(vinylboronate esters). The reactions generate strained (E,E)-1,3-dienes that undergo spontaneous 4π-electrocyclizations to form bicyclic cyclobutenes. Formation of the cyclobutenes is driven by the strain in the medium-ring (E,E)-1,3-diene intermediate. Thermal ring openings of the cyclobutenes give (Z,Z)-1,3-diene products, again for thermodynamic reasons. DFT calculations verified the thermodynamic versus kinetic control of the reactions, and kinetic studies are in excellent agreement with the calculated energy changes. An extension of the tandem coupling/4π-electrocyclization pathway was demonstrated by a palladium(II)-catalyzed oxidative homocoupling/8π-electrocyclization cascade.

Pyridinium 5-[(1,3-diethyl-6-hydroxy-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl(2-methoxyphenylmethyl]-1,3-diethyl-4,6-dioxo-2-thioxopyrimidin-5-ide

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Abdullah Mohamed Asiri

2009-08-01

Full Text Available 1,3-Diethyl-2-thiobarbituric acid reacts with 2-anisaldehyde to form the Michael addition product 2-anisylbis(1,3-diethyl-2-thiobarbitur-5-ylmethanate, which crystallizes as the title pyridinium salt, C5H6N+·C24H29N4O5S2−, when it reacts with the pyridine used to catalyse the reaction. There are two independent ion pairs in the crystal structure. The anion features a methine C atom connected to three six-membered rings; one of the rings carries a hydroxy group, which engages in hydrogen bonding with the carbonyl group belonging to another ring. The monoclinic unit cell emulates an orthorhombic unit cell, and is a twin with a minor twin component of 35%.

1,4-Dihexyloxy-2,5-bis(2-nitrophenylbenzene

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Norma Wrobel

2012-04-01

Full Text Available The title compound, C30H36N2O6, was prepared via twofold Suzuki coupling of a diboronic acid with bromonitrobenzene. The molecule is located on a crystallographic inversion centre. The lateral benzene ring and the central ring make a dihedral angle of 48.75 (14° and the nitro group is twisted by 41.47 (13° out of the plane of the benzene ring. The nitro and hexyloxy groups are in close proximity and the hexyloxy chain adopts an all-anti conformation.

(1S,3S,4S-tert-Butyl N-[1-benzyl-3-hydroxy-5-phenyl-4-(picolinamidopentyl]carbamate

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Jian-Feng Zheng

2008-07-01

Full Text Available The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentylcarbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1° with the phenyl ring of the terminal benzyl group and 14.3 (1° with the other phenyl ring; in the other molecule, the corresponding angles are 12.1 (1 and 10.6 (1°, respectively. The packing is stabilized by intermolecular hydrogen bonds and C—H...π interactions.

Synthesis and 5α-Reductase Inhibitory Activity of C21 Steroids Having 1,4-diene or 4,6-diene 20-ones and 4-Azasteroid 20-Oximes

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Eunsook Ma

2011-12-01

Full Text Available The synthesis and evaluation of 5α-reductase inhibitory activity of some 4-azasteroid-20-ones and 20-oximes and 3β-hydroxy-, 3β-acetoxy-, or epoxy-substituted C21 steroidal 20-ones and 20-oximes having double bonds in the A and/or B ring are described. Inhibitory activity of synthesized compounds was assessed using 5α-reductase enzyme and [1,2,6,7-3H]testosterone as substrate. All synthesized compounds were less active than finasteride (IC50: 1.2 nM. Three 4-azasteroid-2-oximes (compounds 4, 6 and 8 showed good inhibitory activity (IC50: 26, 10 and 11 nM and were more active than corresponding 4-azasteroid 20-ones (compounds 3, 5 and 7. 3β-Hydroxy-, 3β-acetoxy- and 1α,2α-, 5α,6α- or 6α,7α-epoxysteroid-20-one and -20-oxime derivatives having double bonds in the A and/or B ring showed no inhibition of 5α-reductase enzyme.

Crystal structure of (E-2-benzylidene-4-[(3-phenyl-4,5-dihydroisoxazol-5-ylmethyl]-2H-benzo[b][1,4]thiazin-3(4H-one

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Nada Kheira Sebbar

2015-06-01

Full Text Available In the title compound, C25H20N2O2S, the dihydroisoxazole ring exhibits an envelope conformation with the methine atom being the flap, while the 1,4-thiazine ring displays a screw-boat conformation. The six-membered ring fused to the 1,4-thiazine ring makes dihedral angles of 63.04 (2 and 54.7 (2° with the mean planes through the five-membered heterocycle and the attached phenyl ring, respectively. The phenyl group connected to the 1,4-thiazine ring is disordered over two sites [major component = 0.57 (2]. The most prominent interactions in the crystal structure are C—H...O hydrogen bonds that link molecules, forming inversion dimers, and C—H...N hydrogen bonds that link the dimers into columns parallel to the b axis.

3-Phenoxymethyl-6-phenyl-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

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Shaaban K. Mohamed

2016-04-01

Full Text Available In the title compound, C16H12N4OS, the bicyclic triazolothiadiazole core is approximately planar, with an r.m.s. deviation of 0.018 Å. The phenyl rings are inclined to its mean plane by 7.66 (7 and 71.79 (7°. In the crystal, molecules are linked via a C—H...π interaction and a π–π interaction [intercentroid distance = 3.2942 (9 Å] involving inversion-related triazole rings. These interactions result in the formation of chains propagating along [10-1].

Role of biotransformation, sorption and mineralization of "1"4C-labelled sulfamethoxazole under different redox conditions

International Nuclear Information System (INIS)

Alvarino, T.; Nastold, P.; Suarez, S.; Omil, F.; Corvini, P.F.X.; Bouju, H.

2016-01-01

"1"4C-sulfamethoxazole biotransformation, sorption and mineralization was studied with heterotrophic and autotrophic biomass under aerobic and anoxic conditions, as well as with anaerobic biomass. The "1"4C-radiolabelled residues distribution in the solid, liquid and gas phases was closely monitored along a total incubation time of 190 h. Biotransformation was the main removal mechanism, mineralization and sorption remaining below 5% in all the cases, although the presence of a carbon source exerted a positive effect on the mineralization rate by the aerobic heterotrophic bacteria. In fact, an influence of the type of primary substrate and the redox potential was observed in all cases on the biotransformation and mineralization rates, since an enhancement of the removal rate was observed when an external carbon source was used as a primary substrate under aerobic conditions, while a negligible effect was observed under nitrifying conditions. In the liquid phases collected from all assays, up to three additional peaks corresponding to "1"4C-radiolabelled residues were detected. The highest concentration was observed under anaerobic conditions, where two radioactive metabolites were detected representing each around 15% of the total applied radioactivity after 180 h incubation. One of the metabolites detected under anoxic and anaerobic conditions, is probably resulting from ring cleavage of the isoxazole ring. - Highlights: • New procedure based on "1"4C to determine sulfamethoxazole (SMX) removal • Complete SMX mass balances in solid, liquid and gas phases • Quantification of SMX biotransformation, mineralization and sorption • Influence of the primary metabolism and redox potential on SMX removal • SMX metabolites have been detected and a possible chemical structure was proposed.

Synthesis and muscarinic receptor pharmacology of a series of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridine bioisosteres of arecoline

DEFF Research Database (Denmark)

Pedersen, H; Bräuner-Osborne, H; Ball, R G

1999-01-01

A series of O- and ring-alkylated derivatives of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridin-3-ol was synthesized via treatment of appropriately substituted 4-benzylamino-1,2,5,6-tetrahydropyridine-3-carboxamides with hydrogen sulfide and subsequent ring closure by oxidation with bromine. The mus...

1-Bromo-2,4,6-tricyclohexylbenzene

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Joel T. Mague

2008-01-01

Full Text Available The title compound, C24H25Br, packs efficiently in the crystal structure with no solvent-accessible voids and several intermolecular H...H contacts approximating the sum of the van der Waals radii. The molecule is quite crowded, with intramolecular Br...H and C...H contacts ca 0.38 and 0.30 Å, respectively, less than the sum of the corresponding van der Waals radii. All cyclohexyl rings adopt chair conformations with the `seat' of the chair inclined at approximately 57–81° to the mean plane of the benzene ring, while those ortho to bromine have their centroids displaced in opposite directions from this plane.

Crystal structure of 1-[(6-chloropyridin-3-ylsulfonyl]-1,2,3,4-tetrahydroquinoline

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S. Jeyaseelan

2015-06-01

Full Text Available The tetrahydropyridine ring of the quinoline system in the title compound, C14H13ClN2O2S, adopts a half-chair conformation with the bond-angle sum at the N atom being 350.0°. The dihedral angle between the least-squares planes of the two aromatic rings is 50.13 (11°. In the crystal, inversion dimers linked by pairs of C—H...O hydrogen bonds generate R22(10 loops. Additional intermolecular C—H...O hydrogen bonds generate C(7 chains along [100].

Experimental study on the 4H-SiC-based VDMOSFETs with lightly doped P-well field-limiting rings termination

Science.gov (United States)

He, Yan Jing; Lv, Hong Liang; Tang, Xiao Yan; Song, Qing Wen; Zhang, Yi Meng; Han, Chao; Zhang, Yi Men; Zhang, Yu Ming

2017-03-01

A lightly doped P-well field-limiting rings (FLRs) termination on 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors (VDMOSFETs) has been investigated. Based on the simulation, the proposed termination applied to 4H-SiC VDMOSFET could achieve an almost same breakdown voltage (BV) and have the advantage of lower ion-implantation damage comparing with P+ FLRs termination. Meanwhile, this kind of termination also reduces the difficulty and consumption of fabrication process. 4H-SiC VDMOSFETs with lightly doped P-well (FLRs) termination have been fabricated on 10 μm thick epi-layer with nitrogen doping concentration of 6.2 × 1015 cm-3. The maximum breakdown voltage of the 4H-SiC VDMOSFETs has achieved as high as 1610 V at a current of 15 μA, which is very close to the simulated result of 1643 V and about 90% of the plane parallel breakdown voltage of 1780 V. It is considered that P-well FLRs termination is an effective, robust and process-tolerant termination structure suitable for 4H-SiC VDMOSFET.

Crystal strucutre of rac-methyl (11aR*,12S*,13R*,15aS*,15bS*-11-oxo-11,11a,12,13-tetrahydro-9H,15bH-13,15a-epoxyisoindolo[1,2-c]pyrrolo[1,2-a][1,4]benzodiazepine-12-carboxylate

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Vladimir P. Zaytsev

2014-12-01

Full Text Available The title compound, C21H18N2O4, obtained as a racemate, contains a novel heterocyclic system, viz. isoindolo[1,2-c]pyrrolo[1,2-a][1,4]benzodiazepine. The central diazepane ring has a distorted boat conformation with two phenylene-fused and one methine C atom deviating by 0.931 (1, 0.887 (1 and 0.561 (1 Å, respectively, from the mean plane of the rest of the ring. The γ-lactone ring has an envelope conformation, with the C atom opposite to amide bond deviating by 0.355 (1 Å from its plane. In the crystal, molecules form centrosymmetric dimers through pairs of C—H...O hydrogen bonds.

(E-1-(2-Aminophenyl-3-(4-chlorophenylprop-2-en-1-one

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Rodrigo Abonia

2016-10-01

Full Text Available The title chalcone (E-1-(2-aminophenyl-3-(4-chlorophenylprop-2-en-1-one was prepared with an excellent yield from a Claisen–Schmidt condensation reaction between o-aminoacetophenone and p-chlorobenzaldehyde. This product will be used as a key precursor for the development of an alternative route for the total synthesis of dubamine and graveoline alkaloids. Single crystals of the title compound suitable for X-ray diffraction were grown via slow evaporation in ethanol at room temperature. A complete crystallographic study was performed in depth to unequivocally confirm its structure and determine some interesting supramolecular properties. The crystal structure of the title o-aminochalcone, C15H12ClNO, shows two molecules per asymmetric unit (Z′ = 2 and adopts an E configuration about the C=C double bond. In the title compound, the mean plane of the non-H atoms of the central chalcone fragment C—C(O—C—C—C is as follows: [r.m.s. deviation = 0.0130 Å for A-B and 0.0043 for C-D molecules]. In the crystal, molecules are linked by N—H...N and C—H...O, hydrogen bonds forming edge-fused R66(46 rings parallel to (100. Additionally, N—H...O hydrogen bonds generate a three-dimensional network.

Synthesis of 1-13C-1-indanone and 2-13C-1,2,3,4-tetrahydroquinoline

International Nuclear Information System (INIS)

Pickering, R.E.; Wysocki, M.A.; Eisenbraun, E.J.

1985-01-01

The synthesis of 2- 13 C-1,2,3,4-tetrahydroquinoline (5) via 1- 13 C-3-phenylpropanoic acid (1), 1- 13 C-1-indanone (2), 1- 13 C-1-indanone hydrazone (3) and 2- 13 C-3,4-dihydro-2(1H)-quinolinone (4) proceeded in 78, 96, 95, 79, and 85% individual yields respectively for 1, 2, 3, 4, 5 and 61% overall yield of the latter from 1. (author)

Structure-activity relationship studies of 1,7-diheteroarylhepta-1,4,6-trien-3-ones with two different terminal rings in prostate epithelial cell models.

Science.gov (United States)

Wang, Rubing; Zhang, Xiaojie; Chen, Chengsheng; Chen, Guanglin; Sarabia, Cristian; Zhang, Qiang; Zheng, Shilong; Wang, Guangdi; Chen, Qiao-Hong

2017-06-16

To systematically investigate the structure-activity relationships of 1,7-diheteroarylhepta-1,4,6-trien-3-ones in three human prostate cancer cell models and one human prostate non-neoplastic epithelial cell model, thirty five 1,7-diarylhepta-1,4,6-trien-3-ones with different terminal heteroaromatic rings have been designed for evaluation of their anti-proliferative potency in vitro. These target compounds have been successfully synthesized through two sequential Horner-Wadsworth-Emmons reactions starting from the appropriate aldehydes and tetraethyl (2-oxopropane-1,3-diyl)bis(phosphonate). Their anti-proliferative potency against PC-3, DU-145 and LNCaP human prostate cancer cell lines can be significantly enhanced by the manipulation of the terminal heteroaromatic rings, further demonstrating the utility of 1,7-diarylhepta-1,4,6-trien-3-one as a potential scaffold for the development of anti-prostate cancer agents. The optimal analog 40 is 82-, 67-, and 39-fold more potent than curcumin toward the three prostate cancer cell lines, respectively. The experimental data also reveal that the trienones with two different terminal aromatic rings possess greater potency toward three prostate cancer cell lines, but also have greater capability of suppressing the proliferation of PWR-1E benign human prostate epithelial cells, as compared to the corresponding counterparts with two identical terminal rings and curcumin. The terminal aromatic rings also affect the cell apoptosis perturbation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

5,5′-Bis(diethylamino-2,2′-[butane-1,4-diyldioxybis(nitrilomethylidyne]diphenol

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Wen-Kui Dong

2008-04-01

Full Text Available The title complex, C26H38N4O4, was synthesized by the reaction of 4-diethylamino-2-hydroxybenzaldehyde with 1,4-bis(aminooxybutane in ethanol. It crystallizes as discrete centrosymmetric molecules adopting an extended conformation where the two salicylaldoxime groups are separated from each other. Intramolecular O—H...N hydrogen bonding is observed between the hydroxy groups and oxime N atoms. Intermolecular π–π stacking interactions [3.979 (2 Å] between aromatic rings are apparent in the crystal structure. Each ethyl group is disordered over two positions; in one the site occupancy factors are 0.55 and 0.45, in the other 0.53 and 0.47.

(Z-3-Benzyl-2-[(2-phenylcyclohex-2-enylimino]-1,3-thiazolidin-4-one

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Chin Wei Ooi

2012-08-01

Full Text Available The title compound, C22H22N2OS, exists in a Z configuration with respect to the N=C bond. The cyclohexene ring adopts a distorted sofa conformation. The thiazolidine ring is essentially planar, with a maximum deviation of 0.030 (2 Å, and forms dihedral angles of 76.66 (6 and 74.55 (6° with the terminal phenyl rings. The dihedral angle between the phenyl rings is 71.55 (7°. In the crystal, a C—H...π interaction is observed.

4,4′-Dibromo-2,2′-{[(3aS,7aS-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylidene}diphenol

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Augusto Rivera

2011-04-01

Full Text Available The cyclohexane ring in the title compound, C21H24Br2N2O2, adopts a chair conformation and the five-membered ring to which it is fused has a twisted envelope conformation. The asymmetric unit contains one half-molecule, which is related to the other half by a twofold rotation axis. The two N atoms of the five-membered ring are linked to the hydroxy groups by intramolecular O—H...N hydrogen bonds. In the crystal, intermolecular C—H...O and C—H...π interactions occur.

Adsorption configurations of hydrocarbon ring molecules on GaAs(001)-c(4 x 4)

Energy Technology Data Exchange (ETDEWEB)

Passmann, R.; Bruhn, T.; Esser, N.; Vogt, P. [Institut fuer Festkoerperphysik, Technische Universitaet Berlin (Germany); ISAS, Institute for Analytical Sciences, Department Berlin, Berlin (Germany); Nilsen, T.A.; Fimland, B.O. [Department of Electronics and Telecomunications, Norwegian University of Science and Technology, Trondheim (Norway); Kneissl, M. [Institut fuer Festkoerperphysik, Technische Universitaet Berlin (Germany)

2009-07-15

The understanding of self-assembly and bonding mechanisms of organic molecules on semiconductor surfaces represents a central research aspect in the investigation of novel organic/inorganic interfaces and their technological applicability. Here, we investigated the adsorption and bond formation of cyclopentene and 1,4-cyclohexadiene on a GaAs(001)-c(4 x 4) surface in order to clarify the influence of the number of intra-molecular C=C double bonds on the respective adsorption sites. For a determination of the adsorption configuration, the interfaces were characterized electronically and optically by synchrotron based X-ray photoelectron spectroscopy (SXPS), low energy electron diffraction (LEED) and reflectance anisotropy spectroscopy (RAS). The results reveal significantly different adsorption configurations for the two molecules. While cyclopentene bonds with a single covalent bond to the surface, 1,4-cyclohexadiene adsorbs onto the surface by the formation of multiple covalent bonds, e.g. bridge bonds. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

(E-2-[4-(Diethylaminostyryl]-1-methylquinolin-1-ium 4-chlorobenzenesulfonate monohydrate

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Suchada Chantrapromma

2014-04-01

Full Text Available The asymmetric unit of the title hydrated salt, C22H25N2+·C6H4ClO3S−·H2O, comprises two 2-[4-(diethylaminostyryl]-1-methylquinolin-1-ium cations, two 4-chlorobenzenesulfonate anions and two solvent water molecules. One ethyl group of both cations displays disorder over two positions in a 0.659 (2:0.341 (2 ratio in one molecule and in a 0.501 (2:0.499 (2 ratio in the other. The sulfonate group of one anion is also disordered over two positions in a 0.893 (7:0.107 (7 ratio. The dihedral angle between the mean plane of the quinolinium ring system and that of benzene ring is 10.57 (18° in one cation and 14.4 (2° in the other. In the crystal, cations, anions and water molecules are linked into chains along the [010] direction by O—H...Osulfonate hydrogen bonds, together with weak C—H...Osulfonate and C—H...Cl interactions. The cations are stacked by π–π interactions, with centroid–centroid distances in the range 3.675 (2–4.162 (3 Å.

mer-Bis[3,5-difluoro-2-(2-pyridylphenyl-κ2C1,N]{5-(2-pyridyl-κN-3-[3-(4-vinylbenzyloxyphenyl]-1,2,4-triazol-1-ido}iridium(III methanol solvate

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Peter G. Jones

2010-01-01

Full Text Available In the title compound, [Ir(C11H6F2N2(C22H17N4O]·CH3OH, the coordination at iridium is essentially octahedral, but with distortions associated with the bite angles of the ligands [76.25 (9–80.71 (12°] and the differing trans influences of C and N ligands [Ir—N = 2.04 Å (average trans to N but 2.14 Å trans to C]. All three bidentate ligands have coordinating ring systems that are almost coplanar [interplanar angles = 1.7 (1–3.8 (2°]. The vinylbenzyl group is disordered over two positions with occupations of 0.653 (4 and 0.347 (4. The methanol solvent molecule is involved in a classical O—H...N hydrogen bond to a triazole N atom.

Dipole Magnets for the LHeC Ring-Ring Option

CERN Document Server

Tommasini, D; Chritin, R

2012-01-01

The Ring-Ring option of a Large Hadron electron Collider (LHeC) requires 3080 bending magnets, 5.35-meter-long each providing a magnetic field ranging from 0.0127 T at 10 GeV to 0.0763 T at 60 GeV. Main issues in the design of these magnets are the very low injection field, constituting a challenge in achieving a satisfactory field reproducibility from cycle to cycle, and the required compactness to fit in the existing LHC tunnel. This paper describes and discusses a design meeting these requirements, together with its experimental validation by the manufacture and measurement of a 400-mm-long magnet model.

2-(2,4-Dichlorophenyl-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-ylacetamide

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B. Narayana

2013-01-01

Full Text Available In the crystal structure of the title compound, C19H17Cl2N3O2, the molecules form dimers of the R22(10 type through N—H...O hydrogen bonding. As a result of steric repulsion, the amide group is rotated with respect to both the dichlorophenyl and 2,3-dihydro-1H-pyrazol-4-yl rings, making dihedral angles of 80.70 (13 and 64.82 (12°, respectively. The dihedral angle between the dichlorophenyl and 2,3-dihydro-1H-pyrazol-4-yl rings is 48.45 (5° while that between the 2,3-dihydro-1H-pyrazol-4-yl and phenyl rings is 56.33 (6°.

4-twist helix snake to maintain polarization in multi-GeV proton rings

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F. Antoulinakis

2017-09-01

Full Text Available Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC, use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120  GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120  GeV/c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. This snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

Dicty_cDB: Contig-U11598-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available EF534375 |pid:none) Thinopyrum intermedium SGT1 cDNA, ... 49 2e-04 AY365188_1( AY365188 |pid:none) Nicotiana...hqi*nn*lnn*fkkk--- ---skry**yapiyilqlhmvidh*h*n*ln*dqm*mlqqmmaqpplhiatdaedieick sliekgailkmdsdgltpl... Ear... 50 0.13 1 ( EK177296 ) 1095458104244 Global-Ocean-Sampling_GS-31-01-01-1....7 (Q9D4H7) RecName: Full=LON peptidase N-terminal domain and RING ... 57 5e-07 AE014188_398( AE014188 |pid:n... homolog B; Short=... 53 1e-05 (Q496Y0) RecName: Full=LON peptidase N-terminal domain and RING ... 53 1e-05

A new approach to alkaloid-like systems: synthesis and crystal structure of 1-(2-acetyl-11-methoxy-5,6-dihydro[1,3]dioxolo[4,5-g]pyrrolo[2,1-a]isoquinolin-1-ylpropan-2-one

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Le Tuan Anh

2017-11-01

Full Text Available The title compound, C19H19NO5, (I, is the product of a domino reaction between cotarnine chloride and acetylacetylene catalysed by copper(I iodide. The molecule of (I comprises a fused tetracyclic system containing two terminal five-membered rings (pyrrole and 1,3-dioxole and two central six-membered rings (dihydropyridine and benzene. The five-membered 1,3-dioxole ring has an envelope conformation and the central six-membered dihydropyridine ring adopts a twist-boat conformation. The acyl substituent is almost coplanar with the pyrrole ring, whereas the methoxy substituent is twisted by 27.93 (16° relative to the benzene ring. The 2-oxopropan-1-yl substituent is roughly perpendicular to the pyrrole ring. In the crystal, molecules are stacked along the a-axis direction; the stacks are linked by weak C—H...O hydrogen bonds into puckered layers lying parallel to (001.

1,1′,4,5-Tetrahydrotrispiro[1,3,2-diazaphosphole-2,2′-[1,3,5,2,4,6]triazatriphosphinine-4′,6′′-dibenzo[d,f][1,3,2]dioxaphosphepine-6′,6′′′-dibenzo[d,f][1,3,2]dioxaphosphepine] acetone monosolvate

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Krystal R. Fontenot

2013-09-01

Full Text Available The title compound, C26H22N5O4P3·C3H6O, has been achieved in a two-step synthesis that does not require chromatography. This molecule contains a seven-membered spirocyclic ring at two P-atom positions and a five-membered ring containing new P—N bonds at the other P-atom position. Endocyclic torsion angles about the central biphenyl C—C bonds are −41.5 (3 and −44.4 (3°, and P—N bonds of the central P3N3 ring are within the range 1.5665 (17–1.6171 (17 Å, while the P—O distances are in the range 1.5940 (14–1.6041 (14 Å. One N—H group makes an intermolecular N—H...N hydrogen bond, forming centrosymmetric dimers, while the other N—H group makes an N—H...O hydrogen bond to the acetone solvent molecule. The crystal was a two-component non-merohedral twin with ratio 0.811/0.189.

Recent Advances in Ring-Opening Functionalization of Cycloalkanols by C-C σ-Bond Cleavage.

Science.gov (United States)

Wu, Xinxin; Zhu, Chen

2018-06-01

Cycloalkanols prove to be privileged precursors for the synthesis of distally substituted alkyl ketones and polycyclic aromatic hydrocarbons (PAHs) by virtue of cleavage of their cyclic C-C bonds. Direct functionalization of cyclobutanols to build up other chemical bonds (e. g., C-F, C-Cl, C-Br, C-N, C-S, C-Se, C-C, etc.) has been achieved by using the ring-opening strategy. Mechanistically, the C-C cleavage of cyclobutanols can be involved in two pathways: (a) transition-metal catalyzed β-carbon elimination; (b) radical-mediated 'radical clock'-type ring opening. The recent advances of our group for the ring-opening functionalization of tertiary cycloalkanols are described in this account. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

(2E-1-(3-Chlorophenyl-3-(4-chlorophenylprop-2-en-1-one

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Jerry P. Jasinski

2009-11-01

Full Text Available The title compound, C15H10Cl2O, is a chalcone with 3-chlorophenyl and 4-chlorophenyl substituents bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between mean planes of these two chloro-substituted benzene rings is 46.7 (7° compared to 46.0 (1 and 32.4 (1° in similar published sructures. The angles between the mean plane of the prop-2-en-1-one group and the mean planes of the 3-chlorophenyl and 4-chlorophenyl rings are 24.1 (2 and 29.63°, respectively. While no classical hydrogen bonds are present, weak intermolecular C—H...π-ring interactions are observed, which contribute to the stability of crystal packing.

Platinum Catalyzed Ring-Opening of 1,2-Cyclopropanated Sugars with O-Nucleophiles

DEFF Research Database (Denmark)

Beyer, Jürgen; Skaanderup, Philip Robert; Madsen, Robert

1999-01-01

In the presence of a catalytic amount of Zeise's dimer 1,2-cyclopropanated sugars undergo regioselective ring-opening at C-1 with O-nucleophiles including alcohols, phenols and water to produce 2-C-branched carbohydrates.......In the presence of a catalytic amount of Zeise's dimer 1,2-cyclopropanated sugars undergo regioselective ring-opening at C-1 with O-nucleophiles including alcohols, phenols and water to produce 2-C-branched carbohydrates....

Crystal structure of (E-1-(4′-methoxy-[1,1′-biphenyl]-4-yl-3-(3-nitrophenylprop-2-en-1-one

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T. Vidhyasagar

2015-01-01

Full Text Available The title compound, C22H17NO4, crystallizes with two independent molecules (A and B in the asymmetric unit. Each molecule exists as an E isomer with C—C=C—C torsion angles of −175.69 (17 and −178.41 (17° in A and B, respectively. In molecule A, the planes of the terminal benzene rings are twisted by an angle of 26.67 (10°, while the biphenyl unit is non-planar, the dihedral angle between the rings being 30.81 (10°. The dihedral angle between the nitrophenyl ring and the inner phenyl ring is 6.50 (9°. The corresponding values in molecule B are 60.61 (9, 31.07 (8 and 31.05 (9°. In the crystal, molecules are arranged in a head-to-head manner, with the 3-nitrophenyl groups nearly parallel to one another. The A and B molecules are linked to one another via C—H...O hydrogen bonds, forming chains lying parallel to (-320 and enclosing R22(10 and R22(12 ring motifs. The methoxy group in both molecules is positionally disordered with a refined occupancy ratio of 0.979 (4:0.021 (4 for molecule A and 0.55 (4:0.45 (4 for molecule B.

Targeting MUC1-C suppresses polycomb repressive complex 1 in multiple myeloma.

Science.gov (United States)

Tagde, Ashujit; Markert, Tahireh; Rajabi, Hasan; Hiraki, Masayuki; Alam, Maroof; Bouillez, Audrey; Avigan, David; Anderson, Kenneth; Kufe, Donald

2017-09-19

The polycomb repressive complex 1 (PRC1) includes the BMI1, RING1 and RING2 proteins. BMI1 is required for survival of multiple myeloma (MM) cells. The MUC1-C oncoprotein is aberrantly expressed by MM cells, activates MYC and is also necessary for MM cell survival. The present studies show that targeting MUC1-C with (i) stable and inducible silencing and CRISPR/Cas9 editing and (ii) the pharmacologic inhibitor GO-203, which blocks MUC1-C function, downregulates BMI1, RING1 and RING2 expression. The results demonstrate that MUC1-C drives BMI1 transcription by a MYC-dependent mechanism. MUC1-C thus promotes MYC occupancy on the BMI1 promoter and thereby activates BMI1 expression. We also show that the MUC1-C→MYC pathway induces RING2 expression. Moreover, in contrast to BMI1 and RING2, we found that MUC1-C drives RING1 by an NF-κB p65-dependent mechanism. Targeting MUC1-C and thereby the suppression of these key PRC1 proteins was associated with downregulation of the PRC1 E3 ligase activity as evidenced by decreases in ubiquitylation of histone H2A. Targeting MUC1-C also resulted in activation of the PRC1-repressed tumor suppressor genes, PTEN, CDNK2A and BIM . These findings identify a heretofore unrecognized role for MUC1-C in the epigenetic regulation of MM cells.

1,1′-Bicyclohexyl-1,1′-diyl 2,2′-bipyridine-3,3′-dicarboxylate

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Hoong-Kun Fun

2012-06-01

Full Text Available The title compound, C24H26N2O4, lies about a crystallographic twofold rotation axis. The cyclohexane rings adopts a chair conformation. The two pyridine rings form a dihedral angle of 41.02 (4°. In the crystal, molecules are linked via C—H...O and C—H...N hydrogen bonds into a layer parallel to the bc plane.

2-(4-Methylphenyl-5-[({[5-(4-methylphenyl-1,3,4-thiadiazol-2-yl]sulfanyl}methylsulfanyl]-1,3,4-thiadiazole

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Jing-wen Yu

2012-03-01

Full Text Available In the title compound, C19H16N4S4, the molecules exhibit a butterfly conformation, where the thiadiazole and attached benzene rings in two wings are almost coplanar, with dihedral angles of 0.8 (3 and 0.9 (3°, respectively, while the two thiadiazole rings form a dihedral angle of 46.3 (3°.

Atmospheric 14C variations derived from tree rings during the early Younger Dryas

Science.gov (United States)

Hua, Quan; Barbetti, Mike; Fink, David; Kaiser, Klaus Felix; Friedrich, Michael; Kromer, Bernd; Levchenko, Vladimir A.; Zoppi, Ugo; Smith, Andrew M.; Bertuch, Fiona

2009-12-01

Atmospheric radiocarbon variations over the Younger Dryas interval, from ˜13,000 to 11,600 cal yr BP, are of immense scientific interest because they reveal crucial information about the linkages between climate, ocean circulation and the carbon cycle. However, no direct and reliable atmospheric 14C records based on tree rings for the entire Younger Dryas have been available. In this paper, we present (1) high-precision 14C measurements on the extension of absolute tree-ring chronology from 12,400 to 12,560 cal yr BP and (2) high-precision, high-resolution atmospheric 14C record derived from a 617-yr-long tree-ring chronology of Huon pine from Tasmania, Australia, spanning the early Younger Dryas. The new tree-ring 14C records bridge the current gap in European tree-ring radiocarbon chronologies during the early Younger Dryas, linking the floating Lateglacial Pine record to the absolute tree-ring timescale. A continuous and reliable atmospheric 14C record for the past 14,000 cal yr BP including the Younger Dryas is now available. The new records indicate that the abrupt rise in atmospheric Δ 14C associated with the Younger Dryas onset occurs at ˜12,760 cal yr BP, ˜240 yrs later than that recorded in Cariaco varves, with a smaller magnitude of ˜40‰ followed by several centennial Δ 14C variations of 20-25‰. Comparing the tree-ring Δ 14C to marine-derived Δ 14C and modelled Δ 14C based on ice-core 10Be fluxes, we conclude that changes in ocean circulation were mainly responsible for the Younger Dryas onset, while a combination of changes in ocean circulation and 14C production rate were responsible for atmospheric Δ 14C variations for the remainder of the Younger Dryas.

2,3-Bis(2-chlorobenzylnaphthalene-1,4-dione

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Seik Weng Ng

2008-03-01

Full Text Available The title disubstituted naphthalene-1,4-dione, C24H16Cl2O2, has the two chlorobenzyl substituents related by a non-crystallographic twofold rotation axis, generating a chiral conformation; both enantiomers are present. The two chlorobenzene rings are nearly perpendicular to the fused ring system, making angles of 88.8 (1 and 77.5 (1° with it.

Cytoplasmic tethering of a RING protein RBCK1 by its splice variant lacking the RING domain

International Nuclear Information System (INIS)

Yoshimoto, Nobuo; Tatematsu, Kenji; Koyanagi, Tomoyoshi; Okajima, Toshihide; Tanizawa, Katsuyuki; Kuroda, Shun'ichi

2005-01-01

RBCC protein interacting with PKC 1 (RBCK1) is a transcription factor belonging to the RING-IBR protein family and has been shown to shuttle between the nucleus and cytoplasm, possessing both the nuclear export and localization signals within its amino acid sequence. RBCK2, lacking the C-terminal half of RBCK1 including the RING-IBR domain, has also been identified as an alternative splice variant of RBCK1. RBCK2 shows no transcriptional activity and instead it represses the transcriptional activity of RBCK1. Here, we show that RBCK2 is present usually in the cytoplasm containing two Leu-rich regions that presumably serve as a nuclear export signal (NES). Moreover, an NES-disrupted RBCK1 that is mostly localized within the nucleus is translocated to the cytoplasm when coexpressed with RBCK2, suggesting that RBCK2 serves as a cytoplasmic tethering protein for RBCK1. We propose a novel and general function of RING-lacking splice variants of RING proteins to control the intracellular localization and functions of the parental RING proteins by forming a hetero-oligomeric complex

Dimethyl 4,4′-dihydroxy-3,3′-{[(3aRS,7aRS-2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene}dibenzoate

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Augusto Rivera

2011-11-01

Full Text Available The title compound, C25H30N2O6, has the imidazolidine ring in an envelope conformation. There are two intramolecular O—H...N hydrogen-bond interactions with graph-set motif S(6. The cyclohexane ring adopts a slightly distorted chair conformation. One methyl carboxylate substituent forms a dihedral angle of 12.00 (5° with the plane of the benzene ring, while the other methyl carboxylate group is almost coplanar, making a dihedral angle of 2.26 (9°. In the crystal, pairs of intermolecular C—H...O hydrogen bonds form racemic dimers, corresponding to an R22(18 graph-set motif. Further weak C—H...O interactions generate a chain running along the c axis.

C-shaped diastereomers containing cofacial thiophene-substituted quinoxaline rings: synthesis, photophysical properties, and X-ray crystallography.

Science.gov (United States)

DeBlase, Catherine R; Finke, Ryan T; Porras, Jonathan A; Tanski, Joseph M; Nadeau, Jocelyn M

2014-05-16

Synthesis and characterization of two diastereomeric C-shaped molecules containing cofacial thiophene-substituted quinoxaline rings are described. A previously known bis-α-diketone was condensed with an excess of 4-bromo-1,2-diaminobenzene in the presence of zinc acetate to give a mixture of two C-shaped diastereomers with cofacial bromine-substituted quinoxaline rings. After chromatographic separation, thiophene rings were installed by a microwave-assisted Suzuki coupling reaction, resulting in highly emissive diastereomeric compounds that were studied by UV-vis, fluorescence, and NMR spectroscopy, as well as X-ray crystallography. The unique symmetry of each diastereomer was confirmed by NMR spectroscopy. NMR data indicated that the syn isomer has restricted rotation about the bond connecting the thiophene and quinoxaline rings, which was also observed in the solid state. The spectroscopic properties of the C-shaped diastereomers were compared to a model compound containing only a single thiophene-substituted quinoxaline ring. Ground state intramolecular π-π interactions in solution were detected by NMR and UV-vis spectroscopy. Red-shifted emission bands, band broadening, and large Stokes shifts were observed, which collectively suggest excited state π-π interactions that produce excimer-like emissions, as well as a remarkable positive emission solvatochromism, indicating charge-transfer character in the excited state.

N,N′-Bis(2-thienylmethylenebenzene-1,4-diamine

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Nai-Wei Dong

2009-09-01

Full Text Available The Schiff base, C16H12N2S2, has been synthesized by refluxing an ethanolic solution of thiophene-2-carbaldehyde and benzene-1,4-diamine. The center of the benzene ring is located on a crystallographic center of inversion. The dihedral angle between the benzene and thiophene rings is 63.6 (1°.

Dependency of the regio- and stereoselectivity of intramolecular, ring-closing glycosylations upon the ring size

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Patrick Claude

2011-12-01

Full Text Available Phenyl 3,4,6-tri-O-benzyl-2-O-(3-carboxypropionyl-1-thio-β-D-galactopyranoside (1 was condensed via its pentafluorophenyl ester 2 with 5-aminopentyl (4a, 4-aminobutyl (4b, 3-aminopropyl (4c and 2-aminoethyl 4,6-O-benzylidene-β-D-glucopyranoside (4d, prepared from the corresponding N-Cbz protected glucosides 3a–d, to give the corresponding 2-[3-(alkylcarbamoylpropionyl] tethered saccharides 5a–d. Intramolecular, ring closing glycosylation of the saccharides with NIS and TMSOTf afforded the tethered β(1→3 linked disaccharides 6a–c, the α(1→3 linked disaccharides 7a–d and the α(1→2 linked disaccharide 8d in ratios depending upon the ring size formed during glycosylation. No β(1→2 linked disaccharides were formed. Molecular modeling of saccharides 6–8 revealed that a strong aromatic stacking interaction between the aromatic parts of the benzyl and benzylidene protecting groups in the galactosyl and glucosyl moieties was mainly responsible for the observed regioselectivity and anomeric selectivity of the ring-closing glycosylation step.

The 1.4 Å Crystal Structure of the Class D [beta]-Lactamase OXA-1 Complexed with Doripenem

Energy Technology Data Exchange (ETDEWEB)

Schneider, Kyle D.; Karpen, Mary E.; Bonomo, Robert A.; Leonard, David A.; Powers, Rachel A.; (Grand Valley); (Case Western U.-Med)

2010-01-12

The clinical efficacy of carbapenem antibiotics depends on their resistance to the hydrolytic action of {beta}-lactamase enzymes. The structure of the class D {beta}-lactamase OXA-1 as an acyl complex with the carbapenem doripenem was determined to 1.4 {angstrom} resolution. Unlike most class A and class C carbapenem complexes, the acyl carbonyl oxygen in the OXA-1-doripenem complex is bound in the oxyanion hole. Interestingly, no water molecules were observed in the vicinity of the acyl linkage, providing an explanation for why carbapenems inhibit OXA-1. The side chain amine of K70 remains fully carboxylated in the acyl structure, and the resulting carbamate group forms a hydrogen bond to the alcohol of the 6{alpha}-hydroxyethyl moiety of doripenem. The carboxylate attached to the {beta}-lactam ring of doripenem is stabilized by a salt bridge to K212 and a hydrogen bond with T213, in lieu of the interaction with an arginine side chain found in most other {beta}-lactamase-{beta}-lactam complexes (e.g., R244 in the class A member TEM-1). This novel set of interactions with the carboxylate results in a major shift of the carbapenem's pyrroline ring compared to the structure of the same ring in meropenem bound to OXA-13. Additionally, bond angles of the pyrroline ring suggest that after acylation, doripenem adopts the {Delta}{sup 1} tautomer. These findings provide important insights into the role that carbapenems may have in the inactivation process of class D {beta}-lactamases.

Graphical linking of MO multicenter bond index and VB structures. II-5-c rings and 6-c heterocyclic rings

CERN Document Server

Bollini, C G; Giambiagi, M

2001-01-01

Through the graphical method proposed it is possible to set a link between an MO multicenter bond index and VB structures. The value of the index depends on the order of the atoms involved if they are more than three. For 5-c rings three basic structures are required; the eventually different values are 12. Unlike the 6-c case it may happen that different pairs of basic structures are used to build the same polygon. For the 6-c rings including heteroatoms the original degeneracy of benzene splits leading eventually to 60 different I sub r sub i sub n sub g values.

Multiple C-H Bond Activations and Ring-Opening C-S Bond Cleavage of Thiophene by Dirhenium Carbonyl Complexes.

Science.gov (United States)

Adams, Richard D; Dhull, Poonam; Tedder, Jonathan D

2018-06-14

The reaction of Re 2 (CO) 8 (μ-C 6 H 5 )(μ-H) (1) with thiophene in CH 2 Cl 2 at 40 °C yielded the new compound Re 2 (CO) 8 (μ-η 2 -SC 4 H 3 )(μ-H) (2), which contains a bridging σ-π-coordinated thienyl ligand formed by the activation of the C-H bond at the 2 position of the thiophene. Compound 2 exhibits dynamical activity on the NMR time scale involving rearrangements of the bridging thienyl ligand. The reaction of compound 2 with a second 1 equiv of 1 at 45 °C yielded the doubly metalated product [Re 2 (CO) 8 (μ-H)] 2 (μ-η 2 -2,3-μ-η 2 -4,5-C 4 H 2 S) (3), formed by the activation of the C-H bond at the 5 position of the thienyl ligand in 2. Heating 3 in a hexane solvent to reflux transformed it into the ring-opened compound Re(CO) 4 [μ-η 5 -η 2 -SCC(H)C(H)C(H)][Re(CO) 3 ][Re 2 (CO) 8 (μ-H)] (4) by the loss of one CO ligand. Compound 4 contains a doubly metalated 1-thiapentadienyl ligand formed by the cleavage of one of the C-S bonds. When heated to reflux (125 °C) in an octane solvent in the presence of H 2 O, the new compound Re(CO) 4 [η 5 -μ-η 2 -SC(H)C(H)C(H)C(H)]Re(CO) 3 (5) was obtained by cleavage of the Re 2 (CO) 8 (μ-H) group from 4 with formation of the known coproduct [Re(CO) 3 (μ 3 -OH)] 4 . All new products were characterized by single-crystal X-ray diffraction analyses.

2,3-Dibromo-3-(2-bromophenyl-1-(3-phenylsydnon-4-ylpropan-1-one

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Balakrishna Kalluraya

2010-12-01

Full Text Available In the title compound [systematic name: 2,3-dibromo-3-(2-bromophenyl-1-(5-oxido-3-phenyl-1,2,3-oxadiazol-3-ium-4-ylpropan-1-one], C17H11Br3N2O3, the oxadiazole ring is essentially planar, with a maximum deviation of 0.003 (1 Å. The –CHBr–CHBr– chain and bromophenyl ring are disordered over two sets of sites with a refined occupany ratio of 0.756 (5:0.244 (5. The central oxadiazole ring makes dihedral angles of 54.07 (11 and 13.76 (18° with the attached phenyl and the major component of the bromo-substituted benzene rings, respectively. The dihedral angle between the major and minor components of the bromophenyl rings is 13.4 (5°. In the crystal structure, molecules are connected by C—H...O hydrogen bonds, forming [010] ribbons.

/sup 13/C NMR spectra and electron conduction in 4-substituted diphenylamines

Energy Technology Data Exchange (ETDEWEB)

Filimonov, V.D.; Kogan, R.M.; Tverdokhlebova, N.E.; Shcherbakov, V.V.; Kushnarev, D.F.; Kalabin, G.A.

1986-07-10

The /sup 13/C NMR spectra were recorded for a series of 4-X-diphenylamines, and correlations equations relating the /sup 13/C NMR chemical shifts of the C/sup 1/ and C/sup 4/ positions to the electronic characteristics of the substituent X were obtained. It was established that the conduction of the substituted ring in the 4-X-diphenylamines is practically the same as in 4-X-biphenyls. Joint analysis of the spectral characteristics of the diphenylamines, biphenyls, N-substituted anilines, and carbazoles made it possible to conclude that the increased transmission characteristics of the diphenylamines are determined by the conformational mobility of the two benzene rings and by the unidirectional effect of changes in the introduction and resonance factors with variation in the substituent X.

9-(3-Bromo-5-chloro-2-hydroxyphenyl-10-(2-hydroxyethyl-3,6-diphenyl-3,4,9,10-tetrahydroacridine-1,8(2H,5H-dione

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Mehmet Akkurt

2014-06-01

Full Text Available In the title compound, C33H27BrClNO4, the dihydropyridine ring adopts a flattened boat conformation. The molecular conformation is stabilized by an intramolecular O—H...O hydrogen bond, with an S(8 ring motif. In the crystal, O—H...O, C—H...O and C—H...Cl hydrogen bonds, and C—H...π interactions link the molecules, forming a three-dimensional network. In the acridinedione ring system, the two ring C atoms at the 2- and 3-positions, and the C atom at the 6-position and the atoms of the phenyl ring attached to the C atom at the 6-position are disordered over two sets of sites with occupancy ratios of 0.783 (5:0.217 (5 and 0.526 (18:0.474 (18, respectively.

(E-4-Chloro-N-[(E-2-methyl-3-phenylallylidene]aniline

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Jim Simpson

2009-02-01

Full Text Available The title Schiff base compound, C16H14ClN, adopts E configurations with respect to both the C=C and C=N bonds. The dihedral angle between the two aromatic rings is 53.27 (4°, while the plane through the C=C—C=N system is inclined at 9.06 (8° to the benzene ring and 44.92 (5° to the chlorobenzene ring. In the crystal structure, weak C—H...Cl and C—H...N hydrogen bonds stack the molecules down the a axis.

(E-1-(4-Aminophenyl-3-(naphthalen-2-ylprop-2-en-1-one

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Thawanrat Kobkeatthawin

2011-05-01

Full Text Available The molecule of the title chalcone derivative, C19H15NO, exists in a trans configuration with respect to the C=C double bond. The molecule is slightly twisted with a dihedral angle of 6.12 (12° between the benzene ring and the naphthalene ring system. The prop-2-en-1-one bridge is nearly planar, with an r.m.s. deviation of 0.0194 (2, and makes dihedral angles of 8.05 (19 and 11.47 (18° with the benzene ring and the naphthalene ring system, respectively. In the crystal, molecules are linked by N—H...O hydrogen bonds into chains along the b axis. Weak N—H...π and C—H...π interactions and a short N...O contact [2.974 (4 Å] are also observed.

4-(4-Bromophenyl-7,7-dimethyl-2-methylamino-3-nitro-7,8-dihydro-4H-chromen-5(6H-one including an unknown solvate

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S. Antony Inglebert

2014-05-01

Full Text Available In the title compound, C18H19BrN2O4, the chromene unit is not quite planar (r.m.s. deviation = 0.199 Å, with the methyl C atoms lying 0.027 (4 and 1.929 (4 Å from the mean plane of the chromene unit. The six-membered carbocyclic ring of the chromene moiety adopts an envelope conformation, with the dimethyl-substituted C atom as the flap. The methylamine and nitro groups are slightly twisted from the chromene moiety, with C—N—C—O and O—N—C—C torsion angles of 2.7 (4 and −0.4 (4°, respectively. The dihedral angle between the mean plane of the chromene unit and the benzene ring is 85.61 (13°. An intramolecular N—H...O hydrogen bond generates an S(6 ring motif, which stabilizes the molecular conformation. In the crystal, molecules are linked via N—H...O hydrogen bonds, forming hexagonal rings lying parallel to the ab plane. A region of disordered electron density, most probably disordered ethanol solvent molecules, occupying voids of ca 432 Å3 for an electron count of 158, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

(1-Phenyl-1H-1,2,3-triazol-4-ylmethyl pyridine-3-carboxylate

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Zakirjon Karimov

2010-07-01

Full Text Available In the title compound, C15H12N4O2, the dihedral angle between the planes of the nicotinoyloxy fragment and triazole ring is 88.61 (5°. The dihedral angle between the planes of triazole and benzene rings is 16.54 (11°. The crystal structure is stabilized by intermolecular C—H...N, C—H...O and C—H...π(triazole hydrogen bonds and aromatic π–π stacking interactions between the benzene and triazole rings [centroid–centroid distance = 3.895 (1 Å

Crystal structure of 4-aminopyridinium 5-(5-chloro-2,4-dinitrophenyl-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate hemihydrate

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Manickkam Vaduganathan

2014-10-01

Full Text Available The title molecular salt, C5H7N2+·C12H8ClN4O7−·0.5H2O, crystallizes as a hemihydrate. The two rings in the barbiturate anion are not coplanar but make a dihedral angle of 43.17 (16°. The two nitro groups deviate from the ring to which they are attached; the nitro group ortho with respect to the ring junction is more deviated [39.3 (4°] than that in the para position [4.2 (5°], probably to overcome steric hindrance. As a result of this, the latter nitro group is more involved in delocalizing the negative charge of the anion than the former nitro group. In the crystal, the cations and anions are linked via N—H...O hydrogen bonds forming zigzag chains along [10-1]. The chains are linked by O—H...O and C—H...O hydrogen bonds, forming slabs lying parallel to (10-1. Further C—H...O hydrogen bonds link the slabs, forming a three-dimensional structure.

USAHA PENURUNAN PERSENTASE CACAT RING PISTON TIPE 4JA1 PADA PROSES HABANAKASHI MESIN BESLY

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E.V. Yuliana Wibisono

2007-01-01

Full Text Available One of the programs that can be used to improve the quality is Six Sigma program using DMAIC method. The research is performed at PT Baninusa Indonesia (PT. BN producing the 2nd type of 4JA1 piston ring. The program is implemented to decrease the defect proportion The production process performance and the problem priority are known from the CTQ itself. The fish bone diagram is used to determine the causes of the problem. The improvement is performed by determination of the best process parameter through the fullfactorial experiment design. The result is significantly decrease defect proportion by 2.682%. Abstract in Bahasa Indonesia : Salah satu program peningkatan kualitas yang dapat mengakomodasi tuntutan peningkatan kualitas adalah program Six Sigma dengan menggunakan metode DMAIC. Penelitian dilakukan pada PT.Baninusa Indonesia (PT.BN, salah satu perusahaan yang memproduksi produk ring piston tipe 4JA1 jenis 2nd ring. Program digunakan untuk menurunkan persentase cacat produk. Dari CTQ yang ada dapat diketahui kinerja proses produksi saat ini dan prioritas permasalahan. Fish bone diagram digunakan untuk akar penyebab masalah Tindakan perbaikan yang dipilih adalah menentukan parameter proses terbaik dengan menggunakan metode eksperimen full factorial. Hasil penerapan parameter proses tersebut menunjukkan pengurangan yang signifikan terhadap persentase cacat sebesar 2,682%. Kata kunci: metoda six sigma, DMAIC, perbaikan kualitas, karakteristik kualitas kritis, diagram fish bone.

Synthesis of 11-14C-quetiapine, 11-14C-isoclotiapine and 10-(4-methylpiperazin-1-yl)pyrido[4,3-b][1,4]benzothiazepine[10-14C

International Nuclear Information System (INIS)

Naghi Saadatjoo; Mohsen Javaheri; Nuclear Science and Technology Research Institute, Tehran; Nader Saemian; Mohsen Amini

2016-01-01

Quetiapine is one of the most widely used antipsychotic drug which acts as an antagonist for multiple neurotransmitter receptor sites. 2-[2-(4-(Dibenzo[b,f][1,4]thiazepin-11-yl)piperazin-1-yl)ethoxy]ethanol (quetiapine) labeled with carbon-14 in 11-position has been synthesized as part of a 5-step sequence from anthranilic acid-[carboxy- 14 C]. We have presented a convenient synthetic pathway for labeling of quetiapine with carbon-14 by using one-pot procedures from a key thiazepin-11(10H)-one-[11- 14 C] by good radiochemical yield. And also isoclotiapine[11- 14 C], and 10-(4-methylpiperazin-1-yl)pyrido[4,3-b][1,4]benzothiazepine[10- 14 C], synthesized according to this route. (author)

Synthesis of branched and linear 1,4-linked galactan oligosaccharides

DEFF Research Database (Denmark)

Andersen, Mathias C. Franch; Boos, Irene; Kinnaert, Christine

2018-01-01

We report the synthesis of linear and branched (1→4)-D-galactans. Four tetra- and one pentasaccharide were accessed by adopting a procedure of regioselective ring opening of a 4,6-O-naphthylidene protecting group followed by glycosylation using phenyl thioglycoside donros. The binding of the linear...... pentasaccharide with galectin-3 is also investigated by determination of a co-crystal structure. The binding of the (1→4)-linked galactan to Gal-3 highlights oligosaccharides of pectic galactan, which is abundant in the human diet, as putative Gal-3 ligands....

3,5-Bis[1-acetyl-5-(4-chlorophenyl-4,5-dihydro-1H-pyrazol-3-yl]-2,6-dimethylpyridine tetrahydrofuran solvate

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Qun Qian

2008-07-01

Full Text Available In the title compound, C29H27Cl2N5O2·C4H8O, the polycyclic system is composed of three parts: one central pyridine ring substituted by two functionalized pyrazoline rings. The dihedral angles between the central pyridine plane and pyrazoline planes are 5.11 (1 and 13.99 (1°, whereas the dihedral angles between each chlorophenyl plane and the attached pyrazoline planes are 88.65 (1 and 83.87 (1°. Molecules are linked by intermolecular C—H...O hydrogen bonds, forming a three-dimensional network.

(E)-Methyl 3-(3,4-dimeth-oxy-phen-yl)-2-[(1,3-dioxoisoindolin-2-yl)meth-yl]acrylate.

Science.gov (United States)

Kannan, D; Bakthadoss, M; Lakshmanan, D; Murugavel, S

2012-04-01

In the title compound, C(21)H(19)NO(6), the isoindole ring system is essentially planar [maximum deviation = 0.019 (2) Å for the N atom] and is oriented at a dihedral angle of 51.3 (1)° with respect to the benzene ring. The two meth-oxy groups are almost coplanar with the attached benzene ring [C-O-C-C = 3.7 (4) and 4.3 (4)°]. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond, which generates an S(9) ring motif. In the crystal, mol-ecules are linked through bifurcated C-H⋯(O,O) hydrogen bonds having R(1) (2)(5) ring motifs, forming chains along the b-axis direction. The crystal packing is further stabilzed by π-π inter-actions [centriod-centroid distance = 3.463 (1) Å].

(1R,6R,13R,18R-(Z,Z-1,18-Bis[(4R-2,2-dimethyl-1,3-dioxolan-4-yl]-3,16-dimethylene-8,20-diazadispiro[5.6.5.6]tetracosa-7,19-diene

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Stéphanie M. Guéret

2010-07-01

Full Text Available The crystal structure of the title compound, C34H54N2O4, has been solved in order to prove the relative and absolute chirality of the newly-formed stereocentres which were established using an asymmetric Diels–Alder reaction at an earlier stage in the synthesis. This unprecedented stable dialdimine contains a 14-membered ring and was obtained as the minor diastereoisomer in the Diels–Alder reaction. The absolute stereochemistry of the stereocentres of the acetal functionality was known to be R based on the use of a chiral (R-trisubstituted dienophile derived from enantiopure (S-glyceraldehyde. The assignment of the configuration in the dienophile and the title di-aldimine differs from (S-glyceraldehyde due to a change in the priority order of the substituents. The crystal structure establishes the presence of six stereocentres all attributed to be R. The 14-membered ring contains two aldimine bonds [C—N = 1.258 (2 and 1.259 (2 Å]. It adopts a similar conformation to that proposed for trans–trans-cyclotetradeca-1,8-dienes.

N-{4-[4-(4-Fluorophenyl-1-(2-methoxyethyl-2-methylsulfanyl-1H-imidazol-5-yl]-2-pyridyl}-2-methyl-3-phenylpropionamide

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Stefan Laufer

2009-12-01

Full Text Available In the crystal structure of the title compound, C28H29FN4O2S, the imidazole ring makes dihedral angles of 11.85 (7, 73.33 (7 and 22.83 (8° with the 4-fluorophenyl, pyridine and phenyl rings, respectively. The 4-fluorophenyl ring makes dihedral angles of 77.91 (7 and 26.93 (8° with the pyridine and phenyl rings, respectively. The phenyl and pyridine rings are nearly perpendicular, making a dihedral angle of 86.47 (9°. The crystal packing shows an intermolecular N—H...O hydrogen-bonding interaction between the N—H and carbonyl groups of the amide functions.

(3R,6S,7aS-3-Phenyl-6-(phenylsulfanylperhydropyrrolo[1,2-c]oxazol-5-one

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Anthony D. Woolhouse

2009-05-01

Full Text Available Molecules of the title compound [systematic name: (2R,5S,7S-2-phenyl-7-phenylsulfanyl-1-aza-3-oxabicyclo[3.3.0]octan-8-one], C18H17NO2S, form high quality crystals even though they are only packed using C—H...O(carbonyl and weak C—H...S interactions. The dihedral angle between the aromatic rings is 85.53 (5°. The fused rings adopt envelope and twist conformations.

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C2-symmetric building block: a strategy for the synthesis of decanolide natural products

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Bernd Schmidt

2013-11-01

Full Text Available Starting from the conveniently available ex-chiral pool building block (R,R-hexa-1,5-diene-3,4-diol, the ten-membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i a site-selective cross metathesis, (ii a highly diastereoselective extended tethered RCM to furnish a (Z,E-configured dienyl carboxylic acid and (iii a Ru–lipase-catalyzed dynamic kinetic resolution to establish the desired configuration at C9. Ring closure was accomplished by macrolactonization. Curvulide A was synthesized from stagonolide E through Sharpless epoxidation.

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C 2-symmetric building block: a strategy for the synthesis of decanolide natural products.

Science.gov (United States)

Schmidt, Bernd; Kunz, Oliver

2013-01-01

Starting from the conveniently available ex-chiral pool building block (R,R)-hexa-1,5-diene-3,4-diol, the ten-membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i) a site-selective cross metathesis, (ii) a highly diastereoselective extended tethered RCM to furnish a (Z,E)-configured dienyl carboxylic acid and (iii) a Ru-lipase-catalyzed dynamic kinetic resolution to establish the desired configuration at C9. Ring closure was accomplished by macrolactonization. Curvulide A was synthesized from stagonolide E through Sharpless epoxidation.

(E-3-(4-Bromophenyl-1-(3,4-dichlorophenylprop-2-en-1-one

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Rajni Kant

2009-04-01

Full Text Available The molecule of the title compound, C15H9BrCl2O, is shown to be the E isomer, with the 3,4-dichlorobenzoyl and p-bromophenyl substituents in trans positions with respect to the chalcone olefin bond. The molecule is non-planar, the two aromatic rings forming a dihedral angle of 49.58 (1°.

Coordination of {Mo142} Ring to La3+ Provides Elliptical {Mo134La10} Ring with a Variety of Coordination Modes

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Eri Ishikawa

2009-12-01

Full Text Available A28-electron reduced C2h-Mo-blue 34Ǻ outer ring diameter circular ring, [Mo142O429H10(H2O49(CH3CO25(C2H5CO2]30- (≡{Mo142(CH3CO25(C2H5CO2} comprising eight carboxylate-coordinated (with disorder {Mo2} linkers and six defect pockets in two inner rings (four and three for each, respectively, reacts with La3+ in aqueous solutions at pH 3.5 to yield a 28-electron reduced elliptical Ci-Mo-blue ring of formula [Mo134O416H20(H2O46{La(H2O5}4{La(H2O7}4{LaCl2(H2O5}2]10- (≡{Mo134La10}, isolated as the Na10[Mo134O416H20(H2O46{La(H2O5}4{La(H2O7}4{LaCl2(H2O5}2]·144 H2O Na+ salt. The elliptical structure of {Mo134La10} showing 36 and 31 Å long and short axes for the outer ring diameters is attributed to four (A-D modes of LaO9/LaO7Cl2 tricapped-trigonal-prismatic coordination (TTP geometries. Two different LaO2(H2O7 and one LaO2(H2O2Cl2 TTP geometries (as A-C modes for each of two inner rings result from the coordination of all three defect pockets of the inner ring for {Mo142(CH3CO25(C2H5CO2}, and two LaO4(H2O5 TTP geometries (as D mode result from the displacement of two (acetate/propionate-coordinated binuclear {Mo2} linkers with La3+ in each inner ring. The isothermal titration calorimetry (ITC of the ring modification from circle to ellipsoid, showing the endothermic reaction of [La3+]/[{Mo142(CH3CO25(C2H5CO2}] = 6/1 with DH = 22 kJ×mol-1, DS = 172 J×K-1×mol-1, DG = −28 kJ×mol-1, and K = 9.9 ´ 104 M-1 at 293 K, leads to the conclusion that the coordination of the defect pockets to La3+ precedes the replacement of the {Mo2} linkers with La3+. 139La- NMR spectrometry of the coordination of {Mo142(CH3CO25(C2H5CO2} ring to La3+ is also discussed.

Crystal structure of (3S*,4R*-4-fluoro-3-(4-methoxyphenyl-1-oxo-2-phenyl-1,2,3,4-tetrahydroisoquinoline-4-carboxylic acid

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Anna Lehmann

2017-06-01

Full Text Available The title compound, C23H18FNO4, crystallized as a racemate. It exhibits a cis conformation with respect to the F atom and the methine H atom. The piperidine ring has a screw-boat conformation. The methoxyphenyl ring and the phenyl ring are inclined to the mean plane of the isoquinoline ring system by 89.85 (4 and 46.62 (5°, respectively, and by 78.15 (5° to one another. In the crystal, molecules are linked by an O—H...O hydrogen bond forming chains propagating along the a-axis direction. The chains are linked by C—H...F hydrogen bonds, forming layers lying parallel to the ab plane.

DFT calculations on 1,4-dithiine and S-oxygenated derivatives

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E. Vessally

2008-12-01

Full Text Available The molecular structures of 1,4-dithiine and S-oxygenated derivatives are studied using B3LYP/6-311++G** level of theory. These compounds have 8π-electrons in the ring. This led to stabilization of non-planar conformation. DFT calculations show that 1,4-dithiine, C4H4SS, 1,4-dithiine-1-oxide, C4H4SOS, 1,4-dithiine-1,4-dioxide, C4H4SOSO and 1,4-dithiine-1,1,4-trioxide, C4H4SO2SO; have boat conformation. 1,4-dithiine-1,1-dioxide, C4H4SO2S, have a shadow boat conformation. 1,4-dithiine-1,1,4,4-tetraoxide, C4H4SO2SO2, have a planar conformation.

Crystal structure of (1S,2R,4S-1-[(morpholin-4-ylmethyl]-4-(prop-1-en-2-ylcyclohexane-1,2-diol

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Rachid Outouch

2015-01-01

Full Text Available The asymmetric unit of the title compound, C14H25NO3, contains two independent molecules with similar geometry. The morpholine and cyclohexane rings of both molecules adopt a chair conformation. Intramolecular O—H...N hydrogen bonds are observed. In the crystal, molecules are linked by O—H...O hydrogen bonds into chains parallel to the [101] direction. The chains are further connected through C—H...O hydrogen bonds forming undulating layers parallel to the (-101 plane. The absolute configuration was assigned by reference to an unchanging chiral centre in the synthetic procedure.

6-(4-Bromophenyl-2-(4-fluorobenzylimidazo[2,1-b][1,3,4]thiadiazole

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Afshan Banu

2011-04-01

Full Text Available In the title compound, C17H11BrFN3S, the imidazothiadiazole and bromophenyl rings are individually almost planar, with maximum deviations of 0.0215 (4 and 0.0044 (4 Å, respectively, and are inclined at an angle of 27.34 (3° with respect to each other. The dihedral angle between the mean planes of the fluorobenzyl and imidazothiadiazole rings is 79.54 (3°. The crystal structure is stabilized by intermolecular C—H...N interactions resulting in chains of molecules along the b axis.

Polycomb Group Proteins RING1A and RING1B Regulate the Vegetative Phase Transition in Arabidopsis

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Jian Li

2017-05-01

Full Text Available Polycomb group (PcG protein-mediated gene silencing is a major regulatory mechanism in higher eukaryotes that affects gene expression at the transcriptional level. Here, we report that two conserved homologous PcG proteins, RING1A and RING1B (RING1A/B, are required for global H2A monoubiquitination (H2Aub in Arabidopsis. The mutation of RING1A/B increased the expression of members of the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL gene family and caused an early vegetative phase transition. The early vegetative phase transition observed in ring1a ring1b double mutant plants was dependent on an SPL family gene, and the H2Aub status of the chromatin at SPL locus was dependent on RING1A/B. Moreover, mutation in RING1A/B affected the miRNA156a-mediated vegetative phase transition, and RING1A/B and the AGO7-miR390-TAS3 pathway were found to additively regulate this transition in Arabidopsis. Together, our results demonstrate that RING1A/B regulates the vegetative phase transition in Arabidopsis through the repression of SPL family genes.

Crystal structure of 2-[4(E-2,6-bis(4-chlorophenyl-3-ethylpiperidin-4-ylidene]acetamide

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K. Priya

2015-11-01

Full Text Available In the title piperidine derivative, C21H22Cl2N2O, the piperidine ring adopts a chair conformation. The chlorophenyl rings are oriented at an angle of 45.59 (14° with respect to each other. In the crystal, molecules are linked via N—H...O hydrogen bonds, forming C(4 chains along [100]. The chains are linked by C—H...O hydrogen bonds, forming sheets parallel to the ab plane. Within the sheets, there are N—H...π interactions present. The crystal studied was refined as an inversion twin.

Crystal structure of 1-[2-(4-chlorophenyl-4,5-diphenyl-1H-imidazol-1-yl]propan-2-ol

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Shaaban K. Mohamed

2017-01-01

Full Text Available The title compound, C24H21ClN2O, crystallizes with two unique molecules in the asymmetric unit. In each molecule, the central imidazole ring is substituted at the 2-, 4- and 5-positions by benzene rings. The 2-substituted ring carries a Cl atom at the 4-position. One of the imidazole N atoms in each molecule has a propan-2-ol substituent. In the crystal, a series of O—H...N, C—H...O and C—H...Cl hydrogen bonds, augmented by several C—H...π(ring interactions, generate a three-dimensional network of molecules stacked along the a-axis direction.

Divergent Total Syntheses of (-)-Huperzine Q, (+)-Lycopladine B, (+)-Lycopladine C, and (-)-4-epi-Lycopladine D.

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Hong, Benke; Hu, Dachao; Wu, Jinbao; Zhang, Jing; Li, Houhua; Pan, Yingming; Lei, Xiaoguang

2017-07-04

We report herein our synthetic efforts towards the divergent syntheses of (-)-huperzine Q (1), (+)-lycopladine B (2), (+)-lycopladine C (3), and (-)-lycopladine D (4). The 10-step total synthesis of (-)-huperzine Q (1) and the first total syntheses of (+)-lycopladines B (2) and C (3) were accomplished through a series of cascade reactions. Our approach involved a Michael addition/aldol/intramolecular C-alkylation sequence to forge the 6/9 spirocycle ring, and this was followed by an ethylene-accelerated carbonyl-olefin metathesis to construct the common 6/5/9 ring system. Finally, late-stage enamine bromofunctionalization enabled us to access (-)-huperzine Q (1), (+)-lycopladine B (2), and (+)-lycopladine C (3), and a tandem C4-epimerization/retro-Claisen condensation furnished (-)-4-epi-lycopladine D (63). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

(E-Methyl 3-(3,4-dimethoxyphenyl-2-[(1,3-dioxoisoindolin-2-ylmethyl]acrylate

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D. Kannan

2012-04-01

Full Text Available In the title compound, C21H19NO6, the isoindole ring system is essentially planar [maximum deviation = 0.019 (2 Å for the N atom] and is oriented at a dihedral angle of 51.3 (1° with respect to the benzene ring. The two methoxy groups are almost coplanar with the attached benzene ring [C—O—C—C = 3.7 (4 and 4.3 (4°]. The molecular conformation is stabilized by an intramolecular C—H...O hydrogen bond, which generates an S(9 ring motif. In the crystal, molecules are linked through bifurcated C—H...(O,O hydrogen bonds having R12(5 ring motifs, forming chains along the b-axis direction. The crystal packing is further stabilzed by π–π interactions [centriod–centroid distance = 3.463 (1 Å].

(C6H16N2)Zn3(HPO3)4H2O: a new layered zinc phosphite templated by diprotonated trans-1,4-diaminocyclohexane

International Nuclear Information System (INIS)

Wang Yu; Yu Jihong; Li Yi; Du Yu; Xu Ruren; Ye Ling

2003-01-01

Employing trans-1,4-diaminocyclohexane (trans-1,4-DACH) as a template, a new two-dimensional layered zinc phosphite (C 6 H 16 N 2 )Zn 3 (HPO 3 ) 4 H 2 O (1) has been prepared hydrothermally. Single-crystal X-ray diffraction analysis shows that it crystallizes in the monoclinic space group P2 1 /n with a=10.458(2) A, b=14.720(3) A, c=13.079(3) A, β=97.93(3) deg. , V=1994.1(7) A 3 , Z=4, R 1 =0.0349 (I>2σ(I)) and wR 2 =0.0605 (all data). The inorganic layer is built up by alternation of ZnO 4 tetrahedra and HPO 3 pseudo pyramids forming a 4.6.8-net. The sheet is featured by a series of capped six-membered rings. The diprotonated trans-1,4-DACH molecules reside in the interlayer region and interact with the inorganic network through H-bonds

6,7-Dichloro-3-(2,4-dichlorobenzylquinoxalin-2(1H-one

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Jinpeng Zhang

2012-08-01

Full Text Available In the title compound, C15H8Cl4N2O, the quinoxaline ring system is almost planar, with a dihedral angle between the benzene and pyrazine rings of 3.1 (2°. The 2,4-dichlorophenyl ring is approximately perpendicular to the pyrazine ring, with a dihedral angle of 86.47 (13° between them. The crystal packing features intermolecular N—H...O hydrogen bonds and π–π stacking interactions, with centroid–centroid distances in the range 3.699 (3–4.054 (3 Å.

N-(1,3-Dioxo-2,3-dihydro-1H-isoindol-2-yl-4,4′′-difluoro-5′-hydroxy-1,1′:3′,1′′-terphenyl-4′-carboxamide

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Hoong-Kun Fun

2012-09-01

Full Text Available The asymmetric unit of the title compound, C27H16F2N2O4, consists of two crystallographically independent molecules (A and B. In molecule B, the isoindoline-1,3-dione ring system is disordered over two set of sites with a site-occupancy ratio of 0.658 (12:0.342 (12. In molecule A, the fluoro-substituted benzene rings make dihedral angles of 18.36 (8 and 46.37 (8° with the central benzene ring, whereas the corresponding angles are 40.90 (8 and 52.89 (9° in molecule B. The isoindoline ring system in molecule A and the major and minor components of the disordered isoindoline ring system in molecule B make dihedral angles of 58.50 (4, 54.13 (16 and 70.01 (28 °, respectively, with their attached benzene rings, linked through the amide group. An intramolecular O—H...O hydrogen bond generates an S(6 ring in each molecule. In the crystal, molecules are linked by N—H...O, C—H...F and C—H...O hydrogen bonds into sheets lying parallel to the bc plane. The crystal studied was a non-merohedral twin with a refined twin component ratio of 0.9316 (8:0.0684 (8.

The crystal structure of zwitterionic 2-{[(4-iminiumyl-3-methyl-1,4-dihydropyridin-1-ylmethyl]carbamoyl}benzoate hemihydrate

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C. S. Chidan Kumar

2017-07-01

Full Text Available The asymmetric unit of the title compound, C15H15N3O3·0.5H2O, comprises two 2-{[(4-iminiumyl-3-methyl-1,4-dihydropyridin-1-ylmethyl]carbamoyl}benzoate zwitterions (A and B and a water molecule. The dihedral angles between the pyridine and phenyl rings in the zwitterions are 53.69 (10 and 73.56 (11° in A and B, respectively. In the crystal, molecules are linked by N—H...O, O—H...O, C—H...O and C—H...π(ring hydrogen bonds into a three-dimensional network. The crystal structure also features π–π interactions involving the centroids of the pyridine and phenyl rings [centroid–centroid distances = 3.5618 (12 Å in A and 3.8182 (14 Å in B].

{μ-2-[4-(1,3-Benzothiazol-2-ylphenyl]-2-azapropane-1,3-dithiolato-κ4S,S′:S,S′}bis[tricarbonyliron(I

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Da-yong Jiang

2012-03-01

Full Text Available The title compound, [Fe2(C15H12N2S3(CO6], was prepared as an azadithiolatodiiron model for the active site of [FeFe]-hydrogenase. The Fe2S2 core adopts a butterfly shape, with each metal having a pseudo square-pyramidal geometry. The N-substituted azadithiolate is μ2-κ4S,S′:S,S′-coordinated to the Fe(CO3 moieties to form two fused six-membered rings with different conformations. The sum of the C—N—C angles around the N atom [356.85 (15°] indicates a flattening of the trigonal–pyramidal geometry about the N atom and an increase in the degree of sp2-hybridization.

Hydrothermal synthesis and crystal structure of the Ni2(C4H4N2)(V4O12)(H2O)2 and Ni3(C4H4N2)3(V8O23) inorganic-organic hybrid compounds. Thermal, spectroscopic and magnetic studies of the hydrated phase

International Nuclear Information System (INIS)

Larrea, Edurne S.; Mesa, Jose L.; Pizarro, Jose L.; Arriortua, Maria I.; Rojo, Teofilo

2007-01-01

Ni 2 (C 4 H 4 N 2 )(V 4 O 12 )(H 2 O) 2 , 1, and Ni 3 (C 4 H 4 N 2 ) 3 (V 8 O 23 ), 2, have been synthesized using mild hydrothermal conditions at 170 deg. C under autogenous pressure. Both phases crystallize in the P-1 triclinic space group, with the unit-cell parameters, a=7.437(7), b=7.571(3), c=7.564(4) A, α=65.64(4), β=76.09(4), γ=86.25(3) o for 1 and a=8.566(2), b=9.117(2), c=12.619(3) A, α=71.05(2), β=83.48(4), γ=61.32(3) o for 2, being Z=2 for both compounds. The crystal structure of the three-dimensional 1 is constructed from layers linked between them through the pyrazine molecules. The sheets are formed by edge-shared [Ni 2 O 6 (H 2 O) 2 N 2 ] nickel(II) dimers octahedra and rings composed by four [V 4 O 12 ] vanadium(V) tetrahedra linked through vertices. The crystal structure of 2 is formed from vertex shared [VO 4 ] tetrahedra that give rise to twelve member rings. [NiO 4 (C 4 H 4 N 2 ) 2 ] ∞ chains, resulting from [NiO 4 N 2 ] octahedra and pyrazine molecules, give rise to a 3D skeleton when connecting to [VO 4 ] tetrahedra. Diffuse reflectance measurements of 1 indicate a slightly distorted octahedral geometry with values of Dq=880, B=980 and C=2700 cm -1 . Magnetic measurements of 1, carried out in the 5.0-300 K range, indicate the existence of antiferromagnetic couplings with a Neel temperature near to 38 K. - Graphical abstract: Crystal structure of a sheet of Ni 2 (C 4 H 4 N 2 )(V 4 O 12 )(H 2 O) 2

Ligand-Mediated Ring → Cube Transformation in a Catalytic Subnanocluster: Co4O4(MeCN)n with n = 1-6.

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Luo, Sijie; Dibble, Collin J; Duncan, Michael A; Truhlar, Donald G

2014-08-07

We studied the Co4O4 subnanocluster and its MeCN-coated species using density functional theory, and we found that the Co4O4 core presents distinctive structures in bare and ligand-coated species. We propose a possible ligand-mediated ring → cube transformation mechanism during the ligand-coating process of the Co4O4 core due to the stronger binding energies of the MeCN ligands to the 3D distorted cube structure than to the 2D ring and ladder structures; theory indicates that three ligands are sufficient to stabilize the cube structure. Both ring and cube structures are ferromagnetic. Our finding is potentially useful for understanding the catalysis mechanism of Co4O4 species, which have important applications in solar energy conversion and water splitting; these catalysis reactions usually involve frequent addition and subtraction of various ligands and thus possibly involve core rearrangement processes similar to our findings.

(1S*,2S*,4R*,5R*-Cyclohexane-1,2,4,5-tetracarboxylic acid

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Akira Uchida

2014-01-01

Full Text Available The title compound, C10H12O8, a prospective raw material for colourless polyimides which are applied to electronic and microelectronic devices, lies about an inversion centre and the cyclohexane ring adopts a chair conformation. Two crystallographycally independent carboxylic acid groups on adjacent C atoms are in equatorial positions, resulting in a mutually trans conformation. In the crystal, O—H...O hydrogen bonds around an inversion centre and a threefold rotoinversion axis, respectively, form an inversion dimer with an R22(8 motif and a trimer with an R33(12 motif.

11-[Bis(trimethylsilylamino]-2,4-bis(trimethylsilyl-7,8,9,10-tetrahydro-6H-cyclohepta[1,2-b]quinoline

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Ísmail Çelik

2017-06-01

Full Text Available In the title compound, C26H48N2Si4, the cycloheptane ring adopts a chair conformation, while the quinolinyl ring system is almost planar [maximum deviation = 0.040 (3 Å for one of the C atoms carrying a Me3Si group]. In the crystal, in the absence of classical hydrogen bonding, the packing is dominated by van der Waals forces. One of the N-bound trimethylsilyl groups is disordered by rotation about the C—SiMe3 bond, and was modelled over two sets of sites in the ratio 0.873 (8:0.127 (8.

Different molecular conformations co-exist in each of three 2-aryl-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamides: hydrogen bonding in zero, one and two dimensions.

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Narayana, Badiadka; Yathirajan, Hemmige S; Rathore, Ravindranath S; Glidewell, Christopher

2016-09-01

4-Antipyrine [4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti-inflammatory, and new examples are always of potential interest and value. 2-(4-Chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide, C19H18ClN3O2, (I), crystallizes with Z' = 2 in the space group P\\overline{1}, whereas its positional isomer 2-(2-chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide, (II), crystallizes with Z' = 1 in the space group C2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2-chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N-H...O and C-H...O hydrogen bonds to form centrosymmetric four-molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compound N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-(3-methoxyphenyl)acetamide, C20H21N3O3, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N-H...O and C-H...O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen-bonded R2(2)(10) ring is the common structural motif.

(2RS-2-(2,4-Difluorophenyl-1-[(4-iodobenzyl(methylamino]-3-(1H-1,2,4-triazol-1-ylpropan-2-ol

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Hui-Ping Xiong

2012-08-01

Full Text Available In the title compound (common name: iodiconazole, C19H19F2IN4O, there is an intramolecular O—H...N hydrogen bond and molecules are linked by weak interactions only, namely C—H...N, C—H...O and C—H...F hydrogen bonds, and π-electron ring–π-electron ring interactions between the triazole rings with centroid–centroid distances of 3.725 (3 Å.

4-(2,4-Dichlorophenyl-6-(1H-indol-3-yl-2,2′-bipyridine-5-carbonitrile

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M. N. Ponnuswamy

2009-05-01

Full Text Available The title compound, C25H14Cl2N4, crystallizes with two independent molecules in the asymmetric unit. The two pyridine rings are almost coplanar, making dihedral angles of 3.2 (1 and 8.6 (1° in the two independent molecules. The dichlorophenyl and indole rings are twisted away from the bipyridine ring by 64.32 (5 and 18.46 (4°, respectively in the first molecule and by 51.0 (1 and 27.99 (5°, respectively in the second molecule. The crystal packing is stabilized by C—H...N, C—H...Cl, N—H...N and C—H...π interactions.

Crystal structure of 4,4′-bis[3-(piperidin-1-ylprop-1-yn-1-yl]-1,1′-biphenyl

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Anqi Walbaum

2017-06-01

Full Text Available The title compound, C28H32N2, (I, is one of a second generation of compounds designed and synthesized based on a very potent and selective α9α10 nicotinic acetylcholine receptor antagonist ZZ161C {1,1′-[[1,1′-biphenyl]-4,4′-diylbis(prop-2-yne-3,1-diyl]bis(3,4-dimethylpyridin-1-ium bromide}, which has shown analgesic effects in a chemotherapy-induced neuropathy animal model. Compound (I was synthesized by the reaction of 4,4′-bis(3-bromoprop-1-yn-1-yl-1,1′-biphenyl with piperidine at room temperature in acetonitrile. The single-crystal used for X-ray analysis was obtained by dissolving (I in a mixture of dichloromethane and methanol, followed by slow evaporation of the solvent. In the crystal of (I, the biphenyl moiety has a twisted conformation, with a dihedral angle of 25.93 (4° between the benzene rings. Both piperidine head groups in (I are in the chair conformation and are oriented so that the N-atom lone pairs of each piperidine group point away from the central biphenyl moiety.

One-pot synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole.

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Tam, Teck Lip; Li, Hairong; Wei, Fengxia; Tan, Ke Jie; Kloc, Christian; Lam, Yeng Ming; Mhaisalkar, Subodh G; Grimsdale, Andrew C

2010-08-06

A one-step synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole with use of 1,2,4,5-tetraaminobenzene tetrahydrobromide and thionyl bromide in good yield is reported. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions. The approach offers a quick and easy way to prepare low bandgap materials as compared to the current literature methods.

A conformational study of the adducts of 2'-deoxythymidine and 2,2,6,6-tetramethyl-1,4-piperidone-N-oxyl by sup(1)H and sup(13)C nuclear magnetic resonance

International Nuclear Information System (INIS)

Hruska, F.E.; Berger, Maurice; Cadet, Jean; Remin, Mieczyslaw

1985-01-01

γ-Irradiation of oxygen-free, aqueous solutions of 2'-deoxythymidine in the presence of the organic nitroxide free radical, 2,2,6,6-tetramethyl-1,4-piperidone-N-oxyl (TAN) leads to a complex mixture of products in which the TAN moiety is linked to the C5 or C6 position of a 5,6-saturated thymine ring. Extensive sup(1)H and sup(13)C nmr data are provided for the eight TAN-dT adducts which are produced in the largest amounts. The results show that the conformational properties of the sugar moiety are dependent on the point of attachment of the TAN group and the configuration of the standard thymine ring

1,4-Bis(2-diazoacetylpiperazine

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Tore Bonge-Hansen

2013-08-01

Full Text Available The asymmetric unit of the title compound, C8H10N6O2, contains one-half molecule, which is completed by a crystallographic center of symmetry. The piperazine ring adopts a chair conformation. In the crystal, weak C—H...O interactions link the molecules into layers parallel to the bc plane. The crystal packing also exhibits short N...N contacts of 3.0467 (16 Å between the terminal diazo N atoms from neighbouring molecules.

26 CFR 1.381(c)(4)-1 - Method of accounting.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Method of accounting. 1.381(c)(4)-1 Section 1... TAX (CONTINUED) INCOME TAXES Insolvency Reorganizations § 1.381(c)(4)-1 Method of accounting. (a... section 381(a) applies, an acquiring corporation shall use the same method of accounting used by the...

Absence of torsion for NK_1(R) over associative rings

OpenAIRE

Basu, Rabeya

2010-01-01

When R is a commutative ring with identity, and if k is a natural number with kR = R, then C. Weibel proved that SK_1(R[X]) has no k-torsion. We reprove his result for any associative ring R with identity in which kR = R.

2,2,6-Trimethyl-5-[2-(4-methylphenylethynyl]-4H-1,3-dioxin-4-one

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Ignez Caracelli

2009-11-01

Full Text Available The 1,3-dioxin-4-one ring in the title compound, C16H16O3, is in a half-boat conformation with the quaternary O—C(CH32—O atom lying 0.546 (1 Å out of the plane defined by the remaining five atoms. The crystal structure is consolidated by C—H...O contacts that lead to supramolecular layers.

4-({[6-(4-Chlorobenzyl-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazin-3-yl]sulfanyl}acetyl-3-phenylsydnone

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Hoong-Kun Fun

2011-04-01

Full Text Available In the title syndone (1,2,3-oxadiazol-3-ylium-5-olate compound, C21H16ClN5O4S, the dihedral angle between the benzene and oxadiazole rings is 55.62 (11° and that between the triazine and the chloro-substituted phenyl rings is 82.45 (9°. There is an intramolecular C—H...S hydrogen bond, which generates an S(5 ring motif. In the crystal, inversion dimers linked by pairs of C—H...O hydrogen bonds generate R22(20 loops. The dimers are connected by C—H...N and C—H...O hydrogen bonds.

Crystal structure of 3-({[(morpholin-4-yl)carbono-thio-yl]sulfan-yl}acet-yl)phenyl benzoate.

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Ambekar, Sachin P; Mahesh Kumar, K; Shirahatti, Arun Kumar M; Kotresh, O; Anil Kumar, G N

2014-11-01

In the title compound, C20H19NO4S2, the morpholine ring adopts the expected chair conformation. The central phenyl ring makes dihedral angles of 67.97 (4) and 7.74 (3)°, respectively, with the benzoate phenyl ring and the morpholine mean plane. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming zigzag chains along the b-axis direction. C-H⋯π inter-actions link centrosymmetrically related mol-ecules, reinforcing the three-dimensional structure.

Ring rearrangements and reactivity of 3-((4-oxo-4H-chromen-3-ylmethylene-4-phenyl-1H-[1,5]benzodiazepin-2(3H-one toward some nucleophiles

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Hanan Salah

2017-05-01

Full Text Available Condensation of 4-phenyl-1H-[1,5]benzodiazepin-2(3H-one (1 with 3-formylchromone (2 afforded a mixture of 3-(chromenylmethylene[1,5]benzodiazepinone 3 and 14-chromenylbenzodiazepino[2,3:6,5]pyrano[2,3-b]benzodiazepine 4. Ring rearrangements of compound 3 with different nucleophilic reagents, such as potassium hydroxide and/or ammonium acetate led to rearrangement into pyranobenzodiazepine 5 and pyridobenzodiazepine 6, respectively. Treatment of compound 3 with hydrazine hydrate, hydroxylamine hydrochloride, malononitrile, cyanothioacetamide, 2-cyano-3,3-disufanylacrylonitrile, and/or 2-cyano-3-phenylamino-3-sufanylacrylonitrile, has been carried out at different conditions, leading to versatile heterocyclic substituted benzodiazepines at position 3, viz. pyrazole 8, isoxazole 9, pyridines 10 and 11, 1,3-dithiine 12, and 1,3-thiazine 13 derivatives.

Crystal structure of [propane-1,3-diylbis(piperidine-4,1-diyl]bis[(pyridin-4-ylmethanone]–4,4′-oxydibenzoic acid (1/1

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Emily M. Low

2014-09-01

Full Text Available In the title co-crystal, C25H32N4O2·C14H10O5, molecules are connected into supramolecular chains aligned along [102] by O—H...N hydrogen bonding. These aggregate into supramolecular layers oriented parallel to (20-1 by C—H...O interactions. These layers then stack in an ABAB pattern along the c crystal direction to give the full three-dimensional crystal structure. The central chain in the dipyridylamide has an anti–anti conformation. The dihedral angle between the aromatic ring planes is 29.96 (3°. Disorder is noted in some of the residues in the structure and this is manifested in two coplanar dispositions of one statistically disordered carboxylic acid group.

Atomic cranks and levers control sugar ring conformations

International Nuclear Information System (INIS)

Zhang Qingmin; Lee, Gwangrog; Marszalek, Piotr E

2005-01-01

In this paper we review the conformational analysis of sugar rings placed under tension during mechanical manipulations of single polysaccharide molecules with the atomic force microscope and during steered molecular dynamics simulations. We examine the role of various chemical bonds and linkages between sugar rings in inhibiting or promoting their conformational transitions by means of external forces. Small differences in the orientation of one chemical bond on the sugar ring can produce significantly different mechanical properties at the polymer level as exemplified by two polysaccharides: cellulose, composed of β-1→4-linked D-glucose, and amylose, composed of α-1→4-linked D-glucose. In contrast to β-glucose rings, which are mechanically stable and produce simple entropic elasticity of the chain, α-glucose rings flip under tension from their chair to a boat-like structure and these transitions produce deviations of amylose elasticity from the freely jointed chain model. We also examine the deformation of two mechanically complementary 1→6-linked polysaccharides: pustulan, a β-1→6-linked glucan, and dextran, a α-1→6-linked glucan. Forced rotations about the C 5 -C 6 bonds govern the elasticity of pustulan, and complex conformational transitions that involve simultaneous C 5 -C 6 rotations and chair-boat transitions govern the elasticity of dextran. Finally, we discuss the likelihood of various conformational transitions in sugar rings in biological settings and speculate on their significance

tert-Butyl 6-bromo-1,4-dimethyl-9H-carbazole-9-carboxylate

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Jean-François Lohier

2010-08-01

Full Text Available The title compound, C19H20BrNO2, consists of a carbazole skeleton with methyl groups at positions 1 and 4, a protecting group located at the N atom and a Br atom at position 6. The pyrrole ring is oriented at dihedral angles of 1.27 (7 and 4.86 (7° with respect to the adjacent benzene rings. The dihedral angle between the benzene rings is 5.11 (7. The crystal structure is determined mainly by intramolecular C—H...O and intermolecular π–π interactions. π-stacking between adjacent molecules forms columns with a parallel arrangement of the carbazole ring systems. The presence of the tert-butoxycarbonyl group on the carbazole N atom and the intramolecular hydrogen bond induce a particular conformation of the exocyclic N—C bond within the molecule.

Crystal structures of 2,3-bis(4-chlorophenyl-1,3-thiazolidin-4-one and trans-2,3-bis(4-chlorophenyl-1,3-thiazolidin-4-one 1-oxide

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Hemant P. Yennawar

2015-03-01

Full Text Available In the crystal structures of the title compounds, C15H11Cl2NOS, (1, and C15H11Cl2NO2S, (2, wherein (2 is the oxidized form of (1, the thiazolidine ring is attached to two chlorophenyl rings. The chlorophenyl ring on the 2-carbon atom position points in the same direction as that of the S atom in (1, while in (2, the S atom points in the opposite direction. The O atom on the chiral S atom in (2 is trans to the chlorophenyl ring on the 2-carbon. The chlorophenyl ring planes in each structure are close to orthogonal, making dihedral angles of 78.61 (6 and 87.46 (8° in (1 and (2, respectively. The thiazolidine ring has a twisted conformation on the S—Cmethine bond in (1, and an envelope conformation with the S atom 0.715 (3 Å out of the plane of other four atoms in (2. In the crystal of (1, molecules are linked by C—H...O hydrogen bonds, as well as by slipped parallel π–π interactions [inter-centroid distance = 3.840 (3 Å] between inversion-related phenyl rings, forming sheets parallel to (001. In the crystal of (2, molecules are linked via C—H...O and C—H...Cl hydrogen bonds, forming slabs parallel to (001.

4-(9-Anthryl-1-(2-methoxyphenylspiro[azetidin-3,9′-xanthen]-2-one

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2009-03-01

Full Text Available The stabilized conformation of the title compound, C36H25NO3, 4-(9-anthryl-1-(2-methoxyphenyl-spiro[azetidin-3,9′-xanthen]-2-one, may be compared with that of the isomeric compound 4-(9-anthryl-1-(4-methoxyphenylspiro[azetidin-3,9′-xanthen]-2-one. In the title isomer, the methoxy group is slightly twisted out of the plane of the attached benzene ring, with a C—O—C—C torsion angle of 31.5 (2°. Its β-lactam ring is essentially planar, with a maximum deviation of −0.021 (1 Å. The β-lactam ring makes dihedral angles of 18.815 (9, 83.33 (7 and 53.62 (8° with the mean planes of the benzene, xanthene and anthracene ring systems, respectively. The structure is stabilized by C—H...π, C—H...N and C—H...O interactions.

1-Methyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H-one

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Mohamed El Hafi

2018-03-01

Full Text Available The title molecule, C6H6N4O, is essentially planar [dihedral angle between the rings = 0.46 (9°]. The crystal structure consists of sheets of molecules lying parallel to (\\overline{1}11 formed by a combination of N—H...O, C—H...O and C—H...H hydrogen bonds. The sheets are connected through π–π stacking interactions.

{1-[(3,5-Dimethyl-4H-1,2,4-triazol-4-ylimino]ethyl}ferrocene

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Mao-Ping Song

2008-10-01

Full Text Available In the title compound, [Fe(C5H5(C11H13N4], the triazolyl and Cp ring form a dihedral angle of 76.6 (3°. In the crystal structure, there are both intra- and intermolecular C—H...π interactions, forming a one-dimensional chain structure along [010].

1,3-Dibenzyl-2-(2-chlorophenyl-4-methylimidazolidine

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Augusto Rivera

2012-12-01

Full Text Available In the title compound, C24H25ClN2, the methine, methylene and methyl C atoms of the methyl-substituted imidazolidine ring are disordered over two sets of sites with a refined occupancy ratio of 0.834 (4:0.166 (4. Each disordered ring assumes an envelope conformation with an N atom as the flap. The pendant benzyl rings are oriented equatorially with respect to the imidazolidine ring. The chlorophenyl ring is inclined to the mean plane of the four planar atoms of the major component of the imidazolidine ring by 76.27 (12°. The dihedral angles between the chlorophenyl ring and the two benzyl rings are 55.31 (9 and 57.50 (8°; the dihedral angle between these latter rings is 71.59 (9°. In the crystal, molecules are linked by C—H...Cl interactions and a number of weak C—H...π interactions, involving all three aromatic rings, forming a three-dimensional structure.

(2E-1-(4-Aminophenyl-3-(2-thienylprop-2-en-1-one ethanol hemisolvate

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Hoong-Kun Fun

2009-10-01

Full Text Available In the title compound, C13H11NOS·0.5C2H6O, the chalcone derivative is close to planar, the dihedral angle between the thiophene and 4-aminophenyl rings being 3.1 (2°. The thiophene ring is disordered over two orientations with occupancies of 0.842 (3 and 0.158 (3. In the crystal structure, molecules are linked into chains along the b axis by N—H...O hydrogen bonds. The chains are crosslinked via N—H...π interactions involving the thiophene ring. The ethanol solvent molecule is also disordered over two positions, each with an occupancy of 0.25.

Crystal structure of 2-amino-N-(2-fluorophenyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide

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K. Chandra Kumar

2015-11-01

Full Text Available In the title compound, C15H15FN2OS, the dihedral angle between the planes of the benzothiophene ring system and the fluorobenzene ring is 3.74 (14°. The six-membered ring of the benzothiophene moiety adopts a half-chair conformation. The molecular conformation is consolidated by intramolecular N—H...F and N—H...O hydrogen bonds. In the crystal, molecules are linked by N—H...O hydrogen bonds, generating C(6 [001] chains.

Crystal structures of three co-crystals of 1,2-bis-(pyridin-4-yl)ethane with 4-alk-oxy-benzoic acids: 4-eth-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), 4-n-propoxybenzoic acid-1,2-bis(pyridin-4-yl)ethane (2/1) and 4-n-but-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1).

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Tabuchi, Yohei; Gotoh, Kazuma; Ishida, Hiroyuki

2015-11-01

The crystal structures of three hydrogen-bonded co-crystals of 4-alk-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), namely, 2C9H10O3·C12H12N2, (I), 2C10H12O3·C12H12N2, (II), and 2C11H14O3·C12H12N2, (III), have been determined at 93, 290 and 93 K, respectively. In (I), the asymmetric unit consists of one 4-eth-oxy-benzoic acid mol-ecule and one half-mol-ecule of 1,2-bis-(pyridin-4-yl)ethane, which lies on an inversion centre. In (II) and (III), the asymmetric units each comprise two crystallographically independent 4-alk-oxy-benzoic acid mol-ecules and one 1,2-bis-(pyridin-4-yl)ethane mol-ecule. In each crystal, the two components are linked by O-H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1unit of the acid and the base. Similar to the structure of 2:1 unit of (I), the units of (II) and (III) adopt nearly pseudo-inversion symmetry. The 2:1 units of (I), (II) and (III) are linked via C-H⋯O hydrogen bonds, forming tape structures.

8-{1-[(4′-Fluoro-[1,1′-biphenyl]-4-ylmethyl]piperidin-4-yl}-3,4-dihydroquinolin-2(1H-one chloroform 0.25-solvate

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Nisar Ullah

2014-02-01

Full Text Available In the asymmetric unit of the title compound, C27H27FN2O·0.25CHCl3, there are two independent molecules (A and B together with a partially disordered chloroform molecule situated about an inversion center. The conformation of the two molecules is very similar. The bridging piperidine rings each have a chair conformation while the piperidin-2-one rings of the quinoline moiety have screw-boat conformations. The benzene rings of the biphenyl moiety are inclined to one another by 26.37 (4 and 23.75 (15° in molecules A and B, respectively. The mean plane of the central piperidine ring [r.m.s. deviation = 0.241 (2 Å in both molecules A and B] is inclined to the benzene ring of the quinoline moiety by 80.06 (4 in A and 83.75 (15° in B, while it is inclined to the adjacent benzene ring of the biphenyl group by 73.623 (15 in A and 75.65 (14° in B. In the crystal, individual molecules are linked by pairs of N—H...O hydrogen bonds, forming A–A and B–B inversion dimers with R22(8 ring motifs. The dimers are stabilized by C—H...O hydrogen bonds and linked via C—H...F and C—H...N hydrogen bonds into a three-dimensional network. Several C—H...π interactions are also present.

Measurement of the ratio of C3+ and O4+ ions produced by ECRIS to prepare a laser cooling experiment at storage rings

International Nuclear Information System (INIS)

Zhu, X.L.; Wen, W.Q.; Ma, X.; Li, J.Y.; Feng, W.T.; Zhang, R.T.; Wang, Enliang; Yan, S.; Guo, D.L.; Hai, B.; Qian, D.B.; Zhang, P.; Xu, S.; Zhao, D.M.; Yang, J.; Zhang, D.C.; Li, B.; Gao, Y.; Huang, Z.K.; Wang, H.B.

2014-01-01

To prepare the upcoming laser cooling of relativistic C 3+ ion beams at the experimental Cooler Storage Ring (CSRe), a novel experiment was performed using a reaction microscope to determine the ratio of C 3+ ions in mixed ion beams of C 3+ and O 4+ that are produced by an Electron Cyclotron Resonance Ion Source (ECRIS). The mixed ion beams at an energy of 4 keV/u were directed to collide on a supersonic helium gas target. Using the single-electron capture channel and the coincidence technique, the fractions of C 3+ and O 4+ ions in the primary beam were obtained. Using different injection gases for ECRIS, including O 2 , CO, CO 2 , and CH 4 , at a fixed radio-frequency power of 300 W, the measured results showed that the fraction of C 3+ ions was greater than 70% for the injection gases of CO and CO 2 . These measured results are very important and helpful for the upcoming laser cooling experiments

Experimental Durability Testing of 4H SiC JFET Integrated Circuit Technology at 727 C

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Spry, David; Neudeck, Phil; Chen, Liangyu; Chang, Carl; Lukco, Dorothy; Beheim, Glenn M

2016-01-01

We have reported SiC integrated circuits (IC's) with two levels of metal interconnect that have demonstrated prolonged operation for thousands of hours at their intended peak ambient operational temperature of 500 C [1, 2]. However, it is recognized that testing of semiconductor microelectronics at temperatures above their designed operating envelope is vital to qualification. Towards this end, we previously reported operation of a 4H-SiC JFET IC ring oscillator on an initial fast thermal ramp test through 727 C [3]. However, this thermal ramp was not ended until a peak temperature of 880 C (well beyond failure) was attained. Further experiments are necessary to better understand failure mechanisms and upper temperature limit of this extreme-temperature capable 4H-SiC IC technology. Here we report on additional experimental testing of custom-packaged 4H-SiC JFET IC devices at temperatures above 500 C. In one test, the temperature was ramped and then held at 727 C, and the devices were periodically measured until electrical failure was observed. A 4H-SiC JFET on this chip electrically functioned with little change for around 25 hours at 727 C before rapid increases in device resistance caused failure. In a second test, devices from our next generation 4H-SiC JFET ICs were ramped up and then held at 700 C (which is below the maximum deposition temperature of the dielectrics). Three ring oscillators functioned for 8 hours at this temperature before degradation. In a third experiment, an alternative die attach of gold paste and package lid was used, and logic circuit operation was demonstrated for 143.5 hours at 700 C.

Anti-leishmanial and structure-activity relationship of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl-2-propen-1-one derivatives

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Asunción Burguete

2008-12-01

Full Text Available A series of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl-2-propen-1-one derivatives were synthesized and tested for in vitro leishmanicidal activity against amastigotes of Leishmania amazonensis in axenical cultures and murine infected macrophages. Structure-activity relationships demonstrated the importance of a radical methoxy at position R3', R4' and R5'. (2E-3-(3,4,5-trimethoxy-phenyl-1-(3,6,7-trimethyl-1,4-dioxy-quinoxalin-2-yl-propenone was the most active. Cytotoxicity on macrophages revealed that this product was almost six times more active than toxic.

3,4-Dimethoxy-4′-nitro-1,1′-biphenyl

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Wen-Yi Chu

2012-05-01

Full Text Available The title compound, C14H13NO4, was prepared through a palladium-catalysed Suzuki–Miyaura coupling reaction. The asymmetric unit comprises two molecules related by pseudo-inversion symmetry. The dihedral angles between the benzene rings in the two molecules are 44.30 (6 and 48.50 (6° while those between the benzene ring and the nitro group are 6.54 (13 and 5.73 (10°. The crystal packing is defined only by Van der Waals interactions.

[A case of mosaic ring chromosome 4 with subtelomeric 4p deletion].

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Kim, Jeong Hyun; Oh, Phil Soo; Na, Hye Yeon; Kim, Sun-Hee; Cho, Hyoun Chan

2009-02-01

Ring chromosome is a structural abnormality that is thought to be the result of fusion and breakage in the short and long arms of chromosome. Wolf-Hirschhorn syndrome (WHS) is a well-known congenital anomaly in the ring chromosome 4 with a partial deletion of the distal short arm. Here we report a 10-month-old male of mosaic ring chromosome 4 with the chief complaint of severe short stature. He showed the height of -4 standard deviation, subtle hypothyroidism and mild atrial septal defect/ventricular septal defect, and also a mild language developmental delay was suspected. Brain magnetic resonance imaging showed multifocal leukomalacia. Chromosomal analysis of the peripheral blood showed the mosaic karyotype with [46,XY,r(4)(p16q35)[84]/45,XY,-4[9]/91,XXYY, dic r(4;4)(p16q35;p16q35)[5]/46,XY,dic r(4;4)(p16q35;p16q35)[2

(Diethyl ether{1-[2-(1-methyl-1H-imidazol-2-yl-κN3-1,1-diphenylethyl]-(1,2,3,3a,7a-η-indenyl}lithium(I

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Maxim V. Borzov

2009-05-01

Full Text Available In the title compound, [Li(C27H23N2(C4H10O], the Li atom possesses a nearly planar trigonal coordination environment (assuming the cyclopentadienyl ring of the indenyl group occupies one coordination place. The diethyl ether ligand adopts a nearly planar W-type conformation.

N-(3-Chloro-4-ethoxy-1-methyl-1H-indazol-5-yl-4-methoxybenzenesulfonamide

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Hakima Chicha

2014-06-01

Full Text Available The indazole ring system of the title compound, C17H18ClN3O4S, is almost planar (r.m.s. deviation = 0.0113 Å and forms dihedral angles of 32.22 (8 and 57.5 (3° with the benzene ring and the mean plane through the 4-ethoxy group, respectively. In the crystal, molecules are connected by pairs of N—H...O hydrogen bonds into inversion dimers, which are further linked by π–π interactions between the diazole rings [intercentroid distance = 3.4946 (11 Å], forming chains parallel to [101].

Asymmetric ring structure of Vps4 required for ESCRT-III disassembly

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Caillat, Christophe; Macheboeuf, Pauline; Wu, Yuanfei; McCarthy, Andrew A.; Boeri-Erba, Elisabetta; Effantin, Gregory; Göttlinger, Heinrich G.; Weissenhorn, Winfried; Renesto, Patricia

2015-12-01

The vacuolar protein sorting 4 AAA-ATPase (Vps4) recycles endosomal sorting complexes required for transport (ESCRT-III) polymers from cellular membranes. Here we present a 3.6-Å X-ray structure of ring-shaped Vps4 from Metallosphera sedula (MsVps4), seen as an asymmetric pseudohexamer. Conserved key interface residues are shown to be important for MsVps4 assembly, ATPase activity in vitro, ESCRT-III disassembly in vitro and HIV-1 budding. ADP binding leads to conformational changes within the protomer, which might propagate within the ring structure. All ATP-binding sites are accessible and the pseudohexamer binds six ATP with micromolar affinity in vitro. In contrast, ADP occupies one high-affinity and five low-affinity binding sites in vitro, consistent with conformational asymmetry induced on ATP hydrolysis. The structure represents a snapshot of an assembled Vps4 conformation and provides insight into the molecular motions the ring structure undergoes in a concerted action to couple ATP hydrolysis to ESCRT-III substrate disassembly.

Ring-substituted 4-Hydroxy-1H-quinolin-2-ones: Preparation and Biological Activity

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Jiri Dohnal

2009-03-01

Full Text Available In the study, a series of twelve ring-substituted 4-hydroxy-1H-quinolin-2-one derivatives were prepared. The procedures for synthesis of the compounds are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity and tested for their photosynthesis-inhibiting activity using spinach (Spinacia oleracea L. chloroplasts. All the synthesized compounds were also evaluated for antifungal activity using in vitro screening with eight fungal strains. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed, as well as their structure-activity relationships (SAR.

4-Fluoro-N-methyl-N-(1,2,3,4-tetra-hydro-carbazol-3-yl)benzene-sulfonamide

DEFF Research Database (Denmark)

Rasmussen, Kaspar Gothardt; Ulven, Trond; Bond, Andrew D

2009-01-01

into layers containing the carbazole units and fluoro-phenyl rings in alternate (200) planes. The carbazole units form centrosymmetric face-to-face inter-actions [inter-planar separation = 4.06 (1) Å] and edge-to-face inter-actions in which the N-H group is directed towards an adjacent carbazole face......, with a shortest H⋯C contact of 2.53 Å. The fluoro-phenyl rings form face-to-face contacts with an approximate inter-planar separation of 3.75 Å and a centroid-centroid distance of 4.73 (1) Å....

Crystal structure of 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl) ethenyl]benzamide: N,N-dimethylformamide (1 : 1)

Energy Technology Data Exchange (ETDEWEB)

Sharma, P. [University of Jammu, X-ray Crystallography Laboratory, Department of Physics (India); Subbulakshmi, K. N.; Narayana, B. [Mangalore University, Department of Chemistry (India); Sarojini, B. K. [Mangalore University, Industrial Chemistry Division, Department of Studies in Chemistry (India); Kant, R., E-mail: rkant.ju@gmail.com [University of Jammu, X-ray Crystallography Laboratory, Department of Physics (India)

2016-03-15

The title compound, 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethenyl] benzamide:N,N-dimethylformamide (1: 1), (C{sub 15}H{sub 11}N{sub 3}O{sub 2}S{sub 2} · C{sub 3}H{sub 7}NO), was synthesized, and its structure was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the monoclinic space group P2{sub 1}/n with a = 10.8714(7), b = 9.0497(5), c = 19.8347(13) Å, β = 91.093(5)°, Z = 4. The crystal structure is stabilized by N–H···S, C–H···O and N–H···O hydrogen bonds. The π···π interactions are also observed between the rings.

A temperature monitor circuit with small voltage sensitivity using a topology-reconfigurable ring oscillator

Science.gov (United States)

Kishimoto, Tadashi; Ishihara, Tohru; Onodera, Hidetoshi

2018-04-01

In this paper, we propose a temperature monitor circuit that exhibits a small supply voltage sensitivity adopting a circuit topology of a reconfigurable ring oscillator. The circuit topology of the monitor is crafted such that the oscillation frequency is determined by the amount of subthreshold leakage current, which has an exponential dependence on temperature. Another important characteristic of the monitor is its small supply voltage sensitivity. The measured oscillation frequency of a test chip fabricated in a 65 nm CMOS process varies only 2.6% under a wide range of supply voltages from 0.4 to 1.0 V at room temperature. The temperature estimation error ranges from -0.3 to 0.4 °C over a temperature range of 10 to 100 °C.

Ethyl 1-cyclopropyl-6,7-difluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate

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De-Cai Wang

2008-11-01

Full Text Available In the title compound, C16H15F2NO4, the dihedral angle between the three-membered ring and the quinoline ring system is 64.3 (3°. In the crystal structure, intermolecular C—H...O hydrogen bonds link the molecules, forming a column running along [101].