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1.
Masood Parvez Oliver E. Edwards Zdzisaw Paryzek 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(4):o249-o251
The structures of 3β‐acetoxy‐9α,11α‐epoxy‐5α‐lanost‐9(11)‐en‐7‐one and 3β‐acetoxy‐9β,11β‐epoxy‐5α‐lanost‐9(11)‐en‐7‐one, C32H52O4, differ in their respective substituted cyclohexanone rings but adopt similar conformations in the other three rings. In both of the crystal structures, weak intermolecular C—H⋯O interactions are present. 相似文献
2.
Hugh W. Thompson Andrew P. J. Brunskill Roger A. Lalancette 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1507-1509
In the monohydrate of the title compound, (+)‐2β,4aα‐dihydroxy‐1,7‐dimethyl‐8‐oxo‐4bβ,7α‐gibbane‐1α,10β‐dicarboxylic acid‐1,4a‐lactone, C19H24O6·H2O, intermolecular hydrogen bonding progresses helically along b from carboxyl to ketone [O?O = 2.694 (5) Å]. The carboxyl and lactone carbonyl groups in translationally related molecules within a helix both accept hydrogen bonds from the same water of hydration. The oxygen of this water in turn accepts a hydrogen bond from the hydroxyl group of a third screw‐related molecule in an adjacent counterdirectionally oriented helix, yielding a complex three‐dimensional hydrogen‐bonding array. Intermolecular O?H—C close contacts were found to the carboxyl and lactone carbonyls, the hydroxyl, and the water. 相似文献
3.
L. C. R. Andrade M. J. M. de Almeida J. A. Paixo F. M. Fernandes Roleira E. J. Tavares da Silva 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(6):o330-o331
The title compound, C21H28O4, has a 4‐acetoxy substituent positioned on the steroid α face. The six‐membered ring A assumes a conformation intermediate between 1α,2β‐half chair and 1α‐sofa. A long Csp3—Csp3 bond is observed in ring B and reproduced in quantum‐mechanical ab initio calculations of the isolated molecule using a molecular‐orbital Hartree–Fock method. Cohesion of the crystal can be attributed to van der Waals interactions and weak C—H...O hydrogen bonds. 相似文献
4.
Hugh W. Thompson Roger A. Lalancette 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):841-843
In the the title compound, 1,7‐dimethyl‐8‐oxo‐4bα,7α‐gibba‐1,3,4a(10a)‐triene‐10β‐carboxylic acid monohydrate, C18H20O3·H2O, the water of hydration accepts a hydrogen bond from the carboxyl and donates hydrogen bonds to the carboxyl carbonyl and the ketone in two different screw‐related neighbors, which are mutually translational, yielding a complex three‐dimensional hydrogen‐bonding array. 相似文献
5.
Guangrong Zheng Sean Parkin Linda P. Dwoskin Peter A. Crooks 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o9-o11
The crystal structures of the title compounds, 2α,4α‐dibenzyl‐3α‐tropanol (2α,4α‐dibenzyl‐8‐methyl‐8‐azabicyclo[3.2.1]octan‐3α‐ol), C22H27NO, (I), and 2α,4α‐dibenzyl‐3β‐tropanol (2α,4α‐dibenzyl‐8‐methyl‐8‐azabicyclo[3.2.1]octan‐3β‐ol), C22H27NO, (II), show that both compounds have a piperidine ring in a chair conformation and a pyrrolidine ring in an envelope conformation. Isomer (I) is asymmetric, the benzyl groups having different orientations, whereas isomer (II) is mirror symmetric, and the N and O atoms, the C atom attached to the hydroxy group, and the methyl C atom attached to the N atom lie on the mirror plane. In the crystal structures of both (I) and (II), the molecules are linked together by intermolecular O—H⋯N hydrogen bonds to form chains that run parallel to the a direction in (I) and parallel to b in (II). 相似文献
6.
L. C. R. Andrade J. A. Paixo M. J. M. de Almeida R. M. L. M. Martins H. I. M. Soares G. J. R. Morais M. J. S. M. Moreno M. L. S e Melo A. S. Campos Neves 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):587-589
The title compound, C23H32O4, has a 3β configuration, with the epoxy O atom at 16α,17α. Rings A and C have slightly distorted chair conformations. Because of the presence of the C5=C6 double bond, ring B assumes an 8β,9α‐half‐chair conformation slightly distorted towards an 8β‐sofa. Ring D has a conformation close to a 14α‐envelope. The acetoxy and acetyl substituents are twisted with respect to the average molecular plane of the steroid. The conformation of the molecule is compared with that given by a quantum chemistry calculation using the RHF–AM1 (RHF = Roothaan Hartree–Fock) Hamiltonian model. Cohesion of the crystal can be attributed to van der Waals interactions and weak intermolecular C—H?O interactions, which link the molecules head‐to‐tail along [101]. 相似文献
7.
Maya Tutughamiarso Michael Bolte Guido Wagner Ernst Egert 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(1):o18-o25
The antibiotic nitrofurantoin {systematic name: (E)‐1‐[(5‐nitro‐2‐furyl)methylideneamino]imidazolidine‐2,4‐dione} is not only used for the treatment of urinary tract infections, but also illegally applied as an animal food additive. Since derivatives of 2,6‐diaminopyridine might serve as artificial receptors for its recognition, we crystallized one potential drug–receptor complex, nitrofurantoin–2,6‐diacetamidopyridine (1/1), C8H6N4O5·C9H11N3O2, (I·II). It is characterized by one N—H...N and two N—H...O hydrogen bonds and confirms a previous NMR study. During the crystallization screening, several new pseudopolymorphs of both components were obtained, namely a nitrofurantoin dimethyl sulfoxide monosolvate, C8H6N4O5·C2H6OS, (Ia), a nitrofurantoin dimethyl sulfoxide hemisolvate, C8H6N4O5·0.5C2H6OS, (Ib), two nitrofurantoin dimethylacetamide monosolvates, C8H6N4O5·C4H9NO, (Ic) and (Id), and a nitrofurantoin dimethylacetamide disolvate, C8H6N4O5·2C4H9NO, (Ie), as well as a 2,6‐diacetamidopyridine dimethylformamide monosolvate, C9H11N3O2·C3H7NO, (IIa). Of these, (Ia), (Ic) and (Id) were formed during cocrystallization attempts with 1‐(4‐fluorophenyl)biguanide hydrochloride. Obviously nitrofurantoin prefers the higher‐energy conformation in the crystal structures, which all exhibit N—H...O and C—H...O hydrogen‐bond interactions. The latter are especially important for the crystal packing. 2,6‐Diacetamidopyridine shows some conformational flexibility depending on the hydrogen‐bond pattern. 相似文献
8.
R. Hema V. Parthasarathi S. Thamotharan S. Dubey D. P. Jindal 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(4):o213-o215
In the title compound, 4‐(3β‐hydroxy‐17‐oxoandrost‐5‐en‐16‐ylidenemethyl)benzonitrile, C27H31NO2, rings A and C of the steroid nucleus are in chair conformations. The central six‐membered ring B is in an 8β,9α‐half‐chair conformation, while the five‐membered ring D adopts a 13β,14α‐half‐chair conformation. The cyanobenzylidene moiety has an E configuration with respect to the carbonyl group at position C17. The dihedral angle between the planes of the steroid nucleus and the cyanobenzylidene moiety is 22.61 (15)°. Intermolecular O—H⃛N hydrogen bonds formed between the hydroxyl group of the steroid and the N atom of the cyanobenzylidene moiety of symmetry‐related molecules link the steroid molecules into chains which run parallel to the b axis. 相似文献
9.
L. C. R. Andrade J. A. Paixo M. J. M. de Almeida E. J. Tavares da Silva M. L. S e Melo F. M. Fernandes Roleira 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(1):o82-o83
The title compound, alternatively called 24‐nor‐5β‐chol‐22‐ene‐3β,7α,12α‐triyl triformate, C26H38O6, has a cis junction between two of the six‐membered rings. All three of the six‐membered rings have chair conformations that are slightly flattened and the five‐membered ring has a 13β,14α‐half‐chair conformation. The 3β, 7α and 12α ring substituents are axial and the 17β group is equatorial. The 3β‐formyloxy group is involved in one weak intermolecular C—H⋯O bond, which links the molecules into dimers in a head‐to‐head fashion. 相似文献
10.
Orhan Büyükgüngr Mustafa Odabaolu idem Albayrak Peter Lnnecke 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o470-o472
The title complex, 2C5H7N2+·C4H2O42−·C4H4O4, contains cyclic eight‐membered hydrogen‐bonded rings involving 2‐aminopyridinium and fumarate ions. The fumaric acid molecules and fumarate ions lie on inversion centers and are linked into zigzag chains by O—H⋯O hydrogen bonds. The dihedral angle between the pyridinium ring and the hydrogen‐bonded fumarate ion is 7.60 (4)°. The fumarate anion is linked to the pyridinium cations by intermolecular N—H⋯O hydrogen bonds. The heterocycle is fully protonated, thus enabling amine–imine tautomerization. 相似文献
11.
R. Hema V. Parthasarathi S. Thamotharan S. Dubey D. P. Jindal 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(7):o421-o422
In the title compound, C31H40N2O·H2O, the outer two six‐membered rings are in chair conformations, while the central ring is in an 8β,9α‐half‐chair conformation. The five‐membered ring adopts a 13β‐envelope conformation and the cyanobenzylidene moiety has an E configuration with respect to the hydroxyl group at position 17. The steroid nuclei are linked by intermolecular O—H?O and O—H?N hydrogen bonds to form a molecular network. The molecular packing has an interesting feature, with the steroids aligned parallel to the b axis, forming a closed loop through hydrogen bonds linked via water molecules. 相似文献
12.
Edwar Corts Rodrigo Abonía Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(1):77-81
In methyl 4‐(4‐chloroanilino)‐3‐nitrobenzoate, C14H11ClN2O4, (I), there is an intramolecular N—H...O hydrogen bond and the intramolecular distances provide evidence for electronic polarization of the o‐quinonoid type. The molecules are linked into sheets built from N—H...O, C—H...O and C—H...π(arene) hydrogen bonds, together with an aromatic π–π stacking interaction. The molecules of methyl 1‐benzyl‐2‐(4‐chlorophenyl)‐1H‐benzimidazole‐5‐carboxylate, C22H17ClN2O2, (II), are also linked into sheets, this time by a combination of C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions. 相似文献
13.
Balasubramanian Sridhar Krishnan Ravikumar 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):o415-o418
In the title compounds, C5H6N5+·C8H7O2−·C8H8O2·H2O, (I), and C5H6N5+·C4H3O4−·H2O, (II), the adeninium cations form N—H...O hydrogen bonds with their anion counterparts and adeninium–adeninium self‐association base pairs with the R22(10) motif (Bernstein et al., 1995). A complete hydrogen‐bonding motif analysis is presented. Conventional hydrogen bonds lead to layer structures in (I) and to two‐dimensional infinite polymeric ribbons in (II). C—H...O interactions are found in both structures, while weak π–π stacking interactions are only observed in (I). 相似文献
14.
Christoph Langes Thomas Gelbrich Ulrich J. Griesser Volker Kahlenberg 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(8):o419-o422
The cation of the title structure [systematic name: (5α,6α)‐6‐hydroxy‐7,8‐didehydro‐4,5‐epoxy‐3‐methoxy‐17‐methylmorphinanium dihydrogen phosphate hemihydrate], C18H22NO3+·H2PO4−·0.5H2O, has a T‐shaped conformation. The dihydrogen phosphate anions are linked by O—H...O hydrogen bonds to give an extended ribbon chain. The codeine cations are linked together by O—H...O hydrogen bonds into a zigzag chain. There are also N—H...O bonds between the two types of hydrogen‐bonded units. Addditionally, they are connected to one another via O...H—O—H...O bridging water molecules. The asymmetric unit contains two codeine hydrogen cations, two dihydrogen phosphate anions and one water molecule. This study shows that the water molecules are firmly bound within a complex three‐dimensional hydrogen‐bonded framework. 相似文献
15.
Andrzej Gzella 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):505-507
The X‐ray crystal structure analyses of 3β‐hydroxy‐11‐oxo‐18α‐olean‐12‐en‐28‐oic acid methyl ester ethanol solvate, C31H48O4·C2H6O, (I), and 3,11‐dioxo‐18α‐olean‐12‐en‐28‐oic acid methyl ester, C31H46O4, (II), are described. These two compounds differ only in the structure of ring A. In (I), ring A has a chair conformation, while in (II), it has a twisted boat conformation. In both compounds, ring C has a slightly distorted sofa conformation, rings B, D and E are in chair conformations, and rings D and E are trans‐fused. The asymmetric unit of (I) contains one molecule of ethanol linked by hydrogen bonds with two different molecules of (I). 相似文献
16.
The title salts, 4‐chloroanilinium hydrogen phthalate (PCAHP), C6H7ClN+·C8H5O4−, 2‐hydroxyanilinium hydrogen phthalate (2HAHP), C6H8NO+·C8H5O4−, and 3‐hydroxyanilinium hydrogen phthalate (3HAHP), C6H8NO+·C8H5O4−, all crystallize in the space group P21/c. The asymmetric unit of 2HAHP contains two independent ion pairs. The hydrogen phthalate ions of 2HAHP and 3HAHP show a short intramolecular O—H...O hydrogen bond, with O...O distances ranging from 2.3832 (15) to 2.3860 (14) Å. N—H...O and O—H...O hydrogen bonds, together with short C—H...O contacts in PCAHP and 3HAHP, generate extended hydrogen‐bond networks. PCAHP forms a two‐dimensional supramolecular sheet extending in the (100) plane, whereas 2HAHP has a supramolecular chain running parallel to the [100] direction and 3HAHP has a two‐dimensional network extending parallel to the (001) plane. 相似文献
17.
Zhi‐Min Jin Hai Feng Bing Tu Mei‐Chao Li Mao‐Lin Hu 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o593-o595
The title complex, C8H6O4·2C6H7N, consists of two crystallographically independent 1:2 clusters of benzene‐1,3‐dicarboxylic acid and 4‐methylpyridine. Each cluster, the components of which are linked by O—H⋯N hydrogen bonds, is almost planar by alignment of C—H⋯O hydrogen bonds. Herring‐bone ribbons of clusters are formed by other C—H⋯O hydrogen bonds, and these ribbons are further packed to form a laminar structure by π–π interactions. 相似文献
18.
Maciej Kubicki Hanna Koenig Zdzisaw Paryzek 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(5):o253-o256
Two isomeric cucurbitane derivatives, 3β,7α,11β‐triacetoxycucurbit‐5(10)‐ene, (I), and 3β,7α,11β‐triacetoxy‐5α‐cucurbit‐1(10)‐ene, (II), both C36H58O6, have their single endocyclic C=C double bonds in different positions. This results in differences in the conformation of the four‐ring system, which is close to a half‐chair/half‐chair/chair/half‐chair arrangement in (I) and to a half‐chair/twist‐boat/boat/half‐chair arrangement in (II). The orientation of some of the substituents is also different; the 3β‐acetoxy group is in an equatorial position in (I) but in an axial position in (II), while the 11β‐acetoxy group occupies an axial position in (I) and an equatorial position in (II). The asymmetric unit of (I) contains two symmetry‐independent molecules which do not differ significantly, being related by a pseudo‐twofold axis of symmetry. In both structures, the aliphatic chain fragments are disordered and the disorder persists at lower temperatures. 相似文献
19.
Naiem Ahmad Wani Vivek Kumar Gupta Rajni Kant Subrayashastry Aravinda Rajkishor Rai 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(8):776-779
The crystal structure of N‐[(1‐{2‐oxo‐2‐[2‐(pyrazin‐2‐ylcarbonyl)hydrazin‐1‐yl]ethyl}cyclohexyl)methyl]pyrazine‐2‐carboxamide monohydrate (Pyr‐Gpn‐NN‐NH‐Pyr·H2O), C19H23N7O3·H2O, reveals an unusual trans–gauche (tg−) conformation for the gabapentin (Gpn) residue around the Cγ—Cβ (θ1) and Cβ—Cα (θ2) bonds. The molecular conformation is stabilized by intramolecular N—H...N hydrogen bonds and weak C—H...O interactions. The packing of the molecules in the crystal lattice shows a network of strong N—H...O and O—H...O hydrogen bonds together with weak C—H...O and π–π inteactions. 相似文献
20.
Christopher Glidewell Debbie Cannon Antonio Quesada John N. Low Susan A. McWilliam Janet M. S. Skakle James L. Wardell 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):455-458
Molecules of 1,3‐diamino‐4‐nitrobenzene, C6H7N3O2, are linked by N—H?O hydrogen bonds [N?O 2.964 (2) and 3.021 (2) Å; N—H?O 155 and 149°] into (4,4) nets. In 3,5‐dinitroaniline, C6H5N3O4, where Z′ = 2, the molecules are linked by three N—H?O hydrogen bonds [N?O 3.344 (2)–3.433 (2) Å and N—H?O 150–167°] into deeply puckered nets, each of which is interwoven with its two immediate neighbours. 相似文献