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1.
Dale C. Swenson Vasu Nair Sanjib Bera 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):e343-e345
We have synthesized two isomeric dideoxynucleosides. 4(S)‐(6‐Amino‐9H‐purin‐9‐yl)‐3‐methylene‐2,3,4,5‐tetrahydrofuran‐2(S)‐ylmethanol, C11H13N5O2, is an analogue of the anti‐HIV compound (S,S)‐isodideoxyadenosine (isoDDA) with an exocyclic methylene group and is found to be anti‐HIV inactive. The solid‐state comformation is very similar to that of isoDDA. 4(S)‐(6‐Amino‐3H‐purin‐3‐yl)‐3‐methylene‐2,3,4,5‐tetrahydrofuran‐2(S)‐ylmethanol, C11H13N5O2, has an isomeric arrangement of the carbohydrate and base moieties, as confirmed by the crystal structure analysis. The asymmetric unit contains two independent molecules that differ in conformations at the sugar moiety. 相似文献
2.
Jrg Schrder Herbert Wenzel Hans‐Georg Stammler Anja Stammler Beate Neumann Harald Tschesche 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):593-596
The title compounds, (2S)‐N‐[5‐(4‐chlorophenyl)‐2,3‐dihydro‐6H‐1,3,4‐thiadiazin‐2‐ylidene]‐2‐[(phenylsulfonyl)amino]propanamide, C18H17ClN4O3S2, (I), (2R)‐N‐[5‐(4‐fluorophenyl)‐6H‐1,3,4‐thiadiazin‐2‐yl]‐2‐[(phenylsulfonyl)amino]propanamide, C18H17FN4O3S2, (II), and (2S)‐N‐[5‐(5‐chloro‐2‐thienyl)‐6H‐1,3,4‐thiadiazin‐2‐yl]‐2‐[(phenylsulfonyl)amino]propanamide, C16H15ClN4O3S3, (III), are potent inhibitors of matrix metalloproteinases. In all three compounds, the thiadiazine ring adopts a screw‐boat conformation. The molecules of compound (I) show a short intramolecular NAla—H?Nexo hydrogen bond [N?N 2.661 (3) Å] and are linked into a chain along the c axis by Nendo—H?Sendo and Nendo—H?OAla hydrogen bonds [N?S 3.236 (3) and N?O 3.375 (3) Å] between neighbouring molecules. In compound (II), the molecules are connected antiparallel into a chain along the a axis by Nexo—H?OAla and NAla—H?Nendo hydrogen bonds [N?O 2.907 (6) and N?N 2.911 (6) Å]. The molecules of compound (III) are dimerized antiparallel through Nexo—H?Nendo hydrogen bonds [N?N 2.956 (7) and 2.983 (7) Å]. The different hydrogen‐bonding patterns can be explained by an amido–imino tautomerism (prototropic shift) shown by different bond lengths within the 6H‐1,3,4‐thiadiazine moiety. 相似文献
3.
Kamlakar Avasthi Sangeeta Aswal Prakas R. Maulik 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(11):1324-1325
In the crystal structure of 1,1′-(1,3-propanediyl)bis(5-ethyl-6-methylthio-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-one), C19H24N8O2S2, the pairs of pyrazolo[3,4-d]pyrimidine rings of the molecule stack between the heterocyclic rings, due to intramolecular π–π interactions. The substituted ethyl and methyl groups are comparable as far as intramolecular stacking is concerned. 相似文献
4.
Yi‐Ping Ye Hong‐Xiang Sun Yuan‐Jiang Pan 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):o397-o398
The title compound, 4‐methoxy‐2‐[(1S,2R,3S,4S,5R)‐3,4,5,6‐tetrahydro‐3,4,5‐trihydroxy‐6‐(hydroxymethyl)‐2H‐pyran‐2‐yl]‐α‐resorcylic acid δ‐lactone monohydrate, C14H16O9·H2O, is a C‐glucoside of 4‐O‐methylgallic acid which has antiasthmatic, antitussive, anti‐inflammatory, antifungal, anti‐HIV and antihepatotoxic activity. The molecule is composed of three six‐membered rings: an aromatic ring, a glucopyranose ring and an annellated δ‐lactone ring. The glucopyranose ring exhibits only small deviations from an ideal chair conformation. The annellated δ‐lactone ring possesses the expected half‐chair conformation. There is one intra‐ and six intermolecular hydrogen bonds which form an extensive hydrogen‐bonding network within the crystal. 相似文献
5.
Ning‐Hai Hu Yasuhiro Kiyota Katsuyuki Aoki 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1284-1286
In the title compound, 3‐[(3,4‐dihydro‐2‐methyl‐4‐oxopyrimidin‐5‐yl)methyl]‐5‐(2‐hydroxyethyl)‐4‐methylthiazolium hexafluorophosphate monohydrate, C12H16N3O2S+·PF6?·H2O, oxythiamine is a monovalent cation with a neutral oxopyrimidine ring. The molecule assumes the F conformation, which is a common form for thiamine but which is substantially different from the unusual V conformation found in the chloride and hydrochloride salts of oxythiamine. The anion‐bridging interaction, C—H?anion?pyrimidine, is emphasized as being important for stabilization of the F conformation. 相似文献
6.
Dale C. Swenson Vasu Nair Sanjib Bera 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e600-e601
We have synthesized a dideoxydidehydronucleoside derivative, 2(S)‐acetoxymethyl‐4‐[4‐amino‐2‐oxopyrimidin‐1(2H)‐yl]‐2,5‐dihydrofuran, C11H13N3O4, which is an analogue of the potently anti‐HIV active compound, dideoxy‐didehydrocytidine (d4C). The target compound crystallizes with two molecules in the asymmetric unit that differ primarily in the orientation of the C6′‐acetyl group. One molecule has an extended conformation and the orientation of the acetyl group in the second molecule gives an unusual hooked‐shaped conformation. The two conformers form A–B dimers via N—H?N hydrogen bonds. The dimers link via N—H?O hydrogen bonds to form chains parallel to the b cell axis. 相似文献
7.
Paul Allen Margaret A. Brimble Peter Turner 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):95-96
The crystal structure of antibiotic CP44,161, 6-(7-{2-ethyl-2-[5-(1-hydroxymethyl)-5-methyl-2,3,4,5-tetrahydro-2-furyl]-4,10,-12-trimethyl-1,6,8-trioxadispiro[4.1.5.3]pentadec-13-en-9-yl}-4-hydroxy-3,5-dimethyl-6-oxononyl)-2-hydroxy-3-methylbenzoic acid monohydrate, C43H66O10·H2O, has been determined by X-ray crystallography. The molecule adopts a cyclic conformation, with a centrally located water molecule contributing to the stability of the conformation through hydrogen-bonding interactions. 相似文献
8.
Chune Dong Junlong Zhang Liangfu Zhang Zuolong Yu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):e21-e21
The crystal structure of the new chiral complex (1R,2R)‐1,2‐diphenyl‐1,2‐bis(8‐quinolinesulfonylamino)‐ ethylenediamine–acetone (1/1), C32H26N4O4S2.C3H6O, is reported. The conformation of the C32H26N4O4S2 (BQSDA) molecule is determined by a bifurcated N—H?N hydrogen‐bond system. The acetone of solvation is linked to the BQSDA molecule by an N—H?O hydrogen bond. 相似文献
9.
Masood Parvez Veejendra K. Yadav Govindaraji Senthil 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):82-85
6-Vinyl-1-oxa-4-thiaspiro[4.5]dec-6-ene has been reacted with dienophiles, such as N-phenylmaleimide (NPM), N-methyltriazoline-2,5-dione (MTAD) and dimethylacetylene dicarboxylate (DMAD), to assess the 1,3-diastereofacial selection caused by the acetal function. In each case, a mixture of two diastereoisomers was produced. The crystal structures of the products of the addition of NPM and MTAD syn to the acetal oxygen, 2-phenyl-2,3,3a,4,5,5a,6,7,8,9,9a,9b-dodecahydro-1H-benz[e]isoindole-6-spiro-2′-[1′,3′]oxathiolane-1,3-dione, C20H21NO3S, (IIa), and 2-methyl-5,7,8,9,10,10a-hexahydro-1H-1,2,4-triazolo[1,2-a]cinnoline-7-spiro-2′-[1′,3′]oxathiolane-1,3-dione, C13H17N3O3S, (IIIa), respectively, and the product of the addition of DMAD syn to the acetal sulfur, dimethyl 1,2,3,4,4a,7-hexahydronaphthalene-1-spiro-2′-[1′,3′]oxathiolane-5,6-dicarboxylate, C16H20O5S, (IVb), have been determined. All three structures are composed of independent molecules separated by normal van der Waals distances. The 1-oxa-4-thia heterocyclic ring has an envelope conformation in the three structures and the S—Csp3 bond distances differ significantly from each other, as observed in comparable structures; the remaining molecular dimensions are as expected. 相似文献
10.
Vukadin M. Leovac Goran A. Bogdanovi Valerija I. eljevi Vladimir Divjakovi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):936-938
The title compound, [diacetylpyridine bis(S‐methylisothiosemicarbazonato)]iodonickel(II), [Ni(C13H18N7S2)I], is the first example of a complex involving the 2N coordination of the isothiosemicarbazide moiety. 2,6‐Diacetylpyridine bis(S‐methylisothiosemicarbazone), as a potentially pentadentate ligand (N5), is coordinated as a tetradentate species, whereby one (deprotonated) isothiosemicarbazide moiety is coordinated in the usual way (1N4N), but the other (neutral) is bonded via the 2N atom only, the fourth ligator being the pyridine nitrogen. The difference in coordination mode of the isothiosemicarbazide moiety is reflected in the 1N—2N bond lengths of 1.359 (4) and 1.379 (3) Å in the deprotonated and undeprotonated moieties, respectively. The structure contains three fused chelate rings in a 5:5:6 arrangement. The six‐membered ring has a non‐planar conformation. 相似文献
11.
Catherine Michaux Bernadette Norberg Jean‐Michel Dogn Franois Durant Bernard Masereel Jacques Delarge Johan Wouters 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1265-1266
Terbogrel, (E)‐6‐[4‐(3‐tert‐butyl‐2‐cyanoguanidino)phenyl]‐6‐(3‐pyridyl)hex‐5‐enoic acid, C23H27N5O2, a mixed thromboxane A2 receptor antagonist and thromboxane A2 synthase inhibitor, shows a hairpin‐like conformation stabilized by an intramolecular hydrogen bond. A structural feature characteristic of the thromboxane A2 synthase inhibitor mode is observed: a distance of 8.4257 (19) Å between the pyridine N atom and the carboxyl group. 相似文献
12.
Il Yoon Ki-Min Park Shim Sung Lee 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(3):321-322
The crystal structure of the tritosylated diethanolamine N,N-bis(tosyloxyethyl)-p-toluenesulfonamide, C25H29NO8S3, has been determined. The conformation of the molecule is such that the tosyl groups are as far apart as possible. The molecules are interconnected by C—H⃛O hydrogen bonds and form columns in the crystal structure. 相似文献
13.
Frank Seela Helmut Rosemeyer Alexander Melenewski Eva‐Maria Heithoff Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o142-o144
In the monohydrate of 2‐amino‐8‐(2‐deoxy‐α‐d ‐erythro‐pentofuranosyl)‐8H‐imidazo[1,2‐a][1,3,5]triazin‐4‐one, C10H13N5O4·H2O, denoted (I) or αZd, the conformation of the N‐glycosylic bond is in the high‐anti range [χ = 87.5 (3)°]. The 2′‐deoxyribofuranose moiety adopts a C2′‐endo,C3′‐exo(2′T3′) sugar puckering (S‐type sugar) and the conformation at the C4′—C5′ bond is ?sc (trans). 相似文献
14.
Andrei S. Batsanov 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):e269-e270
The molecule of 3,5‐difluoro‐4‐nitropyridine N‐oxide, C5H2F2N2O3, is twisted around the C—NO2 bond by 38.5 (1)°, while the 3,5‐diamino analogue, 3,5‐diamino‐4‐nitropyridine N‐oxide monohydrate, C5H6N4O3·H2O, adopts a planar conformation stabilized by intramolecular hydrogen bonds, with a significant redistribution of π electrons. 相似文献
15.
Guido J. Reiss Anja Zimmer Kaspar Hegetschweiler 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):284-288
The structures of 3‐amino‐1,2R,4S,5‐tetraammoniopentane tetrachloride monohydrate, C5H21N54+·4Cl?·H2O, and 1,2R,3,4S,5‐pentaammoniopentane tetrachlorozincate trichloride monohydrate, (C5H22N5)[ZnCl4]Cl3·H2O, have been determined from single‐crystal X‐ray diffraction data. Both compounds show a complex network of N—H?O, O—H?Cl and N—H?Cl hydrogen bonds. There are a total of 14 H atoms of the tetra‐cation and 15 H atoms of the penta‐cation available for hydrogen bonding. However, due to the particular shape of the primary linear polyammonium cations, only a certain number of H atoms can be involved in hydrogen‐bond formation. It is further shown that hydrogen bonding has an influence on the conformation of such alkylammonium cations. 相似文献
16.
Markus Pietsch Martin Nieger Michael Gütschow 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(3):o147-o151
The title compounds, tert‐butyl 6‐benzyl‐2‐(3,3‐diethylureido)‐4,5,6,7‐tetrahydrothieno[2,3‐c]pyridine‐3‐carboxylate, C24H33N3O3S, (I), 7‐benzyl‐2‐diethylamino‐5,6,7,8‐tetrahydro‐3‐oxa‐9‐thia‐1,7‐diazafluoren‐4‐one, C20H23N3O2S, (II), and N‐(7‐benzyl‐4‐oxo‐5,6,7,8‐tetrahydro‐4H‐3,9‐dithia‐1,7‐diazafluoren‐2‐yl)benzamide, C23H19N3O2S2, (III), form monoclinic crystal systems. In (I) and (II), the molecules are linked into a three‐dimensional framework by weak intermolecular C—H⋯O=C hydrogen bonds, whereas in (III) stronger intermolecular N—H⋯O=C interactions are observed. The conformation of (I) is further stabilized by an intramolecular N—H⋯O=C hydrogen bond, which effects the planarity of the ureidothiophenecarboxylate moiety. 相似文献
17.
Intermolecular stacking in pyrazolo[3,4‐d]pyrimidine‐based pentamethylene‐linked flexible molecules
Kamlakar Avasthi Sheikh M. Farooq Ashish K. Tewari Ashoke Sharon Prakas R. Maulik 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(1):o42-o45
The crystal structures of 1‐{5‐[4,6‐bis(methylsulfanyl)‐2H‐pyrazolo[3,4‐d]pyrimidin‐2‐yl]pentyl}‐6‐methylsulfanyl‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C22H29N9S3, and 6‐methylsulfanyl‐1‐{5‐[6‐methylsulfanyl‐4‐(pyrrolidin‐1‐yl)‐2H‐pyrazolo[3,4‐d]pyrimidin‐2‐yl]pentyl}‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C25H34N10S2, which differ in having either a pyrrolidine substituent or a methylsulfanyl group, show intermolecular stacking due to aromatic π–π interactions between the pyrazolo[3,4‐d]pyrimidine rings. 相似文献
18.
Vladimir V. Chernyshev Ksenia A. Paseshnichenko Vadim A. Makarov Eduard J. Sonneveld Hendrik Schenk 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):72-75
In order to correlate the reactivity and molecular structures of dithiocarbamates, the crystal structures of 6-dimethylamino-5-nitropyrimidin-4-yl N,N-diethyldithiocarbamate, C11H17N5O2S2, (Ia), and 6-methylamino-5-nitropyrimidin-4-yl N,N-diethyldithiocarbamate, C10H15N5O2S2, (Ib), and of the product of thermolysis of (Ib), namely 4-diethylamino-6-methylamino-5-nitropyrimidinium chloride monohydrate, C9H16N5O2+·Cl−·H2O, (II), have been determined from X-ray laboratory powder diffraction data. Conformational preferences in (Ia) and (Ib) were studied on the density functional theory (DFT) level. Deviation of the reaction centre of the molecule from planarity and breakage of the secondary S⃛O contact cause switching between two alternative pathways of thermolysis. 相似文献
19.
J. Zukerman‐Schpector Mauricio Vega I. Caracelli Luiz C. Dias Anna M. A. P. Fernandes 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1089-1091
In 6‐methyl‐N‐(4‐nitrobenzoyl)‐5,6‐dihydropyridin‐2(1H)‐one, C13H12N2O4, (I), the piperidone ring is in a distorted half‐chair conformation. In 8‐methoxy‐3‐methyl‐N‐(4‐nitrobenzoyl)‐1,2,3,4,5,6,7,8‐octahydroisoquinoline‐1,6‐dione, C18H20N2O6, (II), the heterocyclic ring is in a slightly distorted half‐boat conformation, while the other six‐membered ring is in a distorted chair conformation. Compound (II) presents a strong intramolecular C—H?O hydrogen bond. In both (I) and (II), the molecules interact through C—H?O interactions. 相似文献
20.
Tullio Pilati Gianluigi Casalone 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o178-o180
The title diastereoisomers, methyl 5‐(S)‐[2‐(S)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate and methyl 5‐(S)‐[2‐(R)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate, both C19H23N3O5, have been studied in two crystalline forms. The first form, methyl 5‐(S)‐[2‐(S)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate–methyl 5‐(S)‐[2‐(R)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate (1/1), 2(S),5(S)‐C19H23N3O5·2(R),5(S)‐C19H23N3O5, contains both S,S and S,R isomers, while the second, methyl 5‐(S)‐[2‐(S)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate, 2(S),5(S)‐C19H23N3O5, is the pure S,S isomer. The S,S isomers in the two structures show very similar geometries, the maximum difference being about 15° on one torsion angle. The differences between the S,S and S,R isomers, apart from those due to the inversion of one chiral centre, are more remarkable, and are partially due to a possible rotational disorder of the 2‐(methoxycarbonyl)tetrahydropyrrole group. 相似文献