共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
Kanji Kubo Nobuo Kato Akira Mori Hitoshi Takeshita 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):644-646
The structures of the title compound, C20H24N2O4S2, and its mercury(II) dichloride complex, dichloro{20‐dicyanomethylene‐5,8,11,14‐tetraoxa‐2,17‐dithiabicyclo[16.4.1]tricosa‐1(23),18,21‐triene‐κ4O,κS17}mercury(II), [HgCl2(C20H24N2O4S2)], have been determined by X‐ray crystallographic analyses. The mercury(II) dichloride complex has two independent molecules of [HgCl2(C20H24N2O4S2)] in the lattice. The mercury(II) ion has pentagonal bipyramidal coordination which involves one S atom, four O atoms and two Cl? ions. 相似文献
3.
R. Malathi S. S. Rajan Geetha Gopalakrishnan G. Suresh 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o681-o682
The title compound, methyl (2aS,3R,5R,5aS,6S,6aS,8R,9aS,10aR,10bR,10cS)‐8‐(3‐furyl)‐2a,4,5,5a,6,6a,8,9,9a,10a,10b,10c‐dodecahydro‐3‐hydroxy‐2a,5a,6a,7‐tetramethyl‐5‐(3‐methylbut‐2‐enoyloxy)‐2H,3H‐cyclopenta[4′,5′]furo[2′,3′:6,5]benzo[cd]isobenzofuran‐6‐acetate, C32H42O8, was isolated from uncrushed green leaves of Azadirachta indica A. Juss (neem) and has been found to possess antifeedant activity against Spodptera litura. The conformations of the functional groups are similar to those of 3‐desacetylsalannin, which was isolated from neem kernels. The molecules are linked into chains by intermolecular O—H?O hydrogen bonds. 相似文献
4.
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
5.
Mustafa OdabasÛoglu igdem Albayrak Orhan Büyükgüngr Peter Lnnecke 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(11):o616-o619
The title compounds, 2‐{[tris(hydroxymethyl)methyl]aminomethylene}cyclohexa‐3,5‐dien‐1(2H)‐one, C11H15NO4, (I), 6‐hydroxy‐2‐{[tris(hydroxymethyl)methyl]aminomethylene}cyclohexa‐3,5‐dien‐1(2H)‐one, C11H15NO5, (II), and 6‐methoxy‐2‐{[tris(hydroxymethyl)methyl]aminomethylene}cyclohexa‐3,5‐dien‐1(2H)‐one, C12H17NO5, (III), adopt the keto–amine tautomeric form, with the formal hydroxy H atom located on the N atom, and the NH group and oxo O atom display a strong intramolecular N—H⋯O hydrogen bond. The N—H⋯O hydrogen‐bonded rings are almost planar and coupled with the cyclohexadiene rings. The carbonyl O atoms accept two other H atoms from the alcohol groups of adjacent molecules in (I), and one from the alcohol and one from the phenol group in (II), but from only one alcohol H atom in (III). 相似文献
6.
Lakshminarasimhan Damodharan Vasantha Pattabhi Rallapalli Sivakumar Sambasivarao Kotha 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):o373-o375
The title compounds, (2R,2′′S,3b′S,4a′R,7b′S,8a′R)‐perhydrodispiro[furan‐2,3′‐dicyclopenta[a,e]pentalene‐7′,2′′‐furan]‐5,5′′‐dione, C20H26O4, and (3aR,3bR,4aR,4bS,5aS,8aR,8bR,9aR,9bS,10aS)‐perhydrodipentaleno[2,1‐a:2′,1′‐e]pentalene‐1,6‐dione, C20H26O2, are intermediates identified during the synthesis of dodecahedrane. Crystallographic studies have established the ring‐junction stereochemistry for these important intermediates. All the ring junctions are cis‐fused, and the molecular packing is stabilized by van der Waals interactions. 相似文献
7.
A. Subbiah Pandi D. Velmurugan S. Shanmuga Sundara Raj Hoong‐Kun Fun P. R. Seshadri D. Thirumalai 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):821-824
10‐(4‐Fluorophenyl)‐3,3,6,6,9‐pentamethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C24H28FNO2, (I), crystallizes with two crystallographically independent molecules (which differ slightly in conformation), while 10‐(4‐fluorophenyl)‐9‐propyl‐3,3,6,6‐tetramethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C26H32FNO2, (II), crystallizes with one molecule per asymmetric unit. In both structures, the central ring in the acridine moiety is in a sofa conformation, while the outer rings adopt intermediate half‐chair/sofa conformations. The central pyridine ring is orthogonal to the substituted phenyl ring. In both structures, the packing of the crystal is stabilized by C—H?O intermolecular hydrogen bonds. 相似文献
8.
Hans‐Joachim Lehmler Sean Parkin 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):e518-e519
The crystal structure of 5‐fluoro‐1‐octanoyluracil [5‐fluoro‐1‐octanoylpyrimidine‐2,4(1H,3H)‐dione, C12H17FN2O3], a lipophilic prodrug of 5‐fluorouracil, is described. The 5‐fluoropyrimidine‐2,4(1H,3H)‐dione moiety is similar to the known structure of 1‐acetyl‐5‐fluorouracil. The 1‐octanoyl group and the 5‐fluorouracil moiety are essentially coplanar, with the octanoyl carbonyl group oriented towards the the ring C—H group and away from the nearer ring carbonyl group. The torsion angle C—N—C—O (from the ring CH group to the octanoyl carbonyl group) of 9.2 (2)° is similar to the corresponding torsion angles reported for 1‐acetyl‐5‐fluorouracil (17.3 and 1.6°) and 1,3‐diacetyl‐5‐fluorouracil (8.8°). 相似文献
9.
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
10.
Dens Konya Christian Philouze Yves Gimbert Andrew E. Greene 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):o108-o111
Three chiral electron‐deficient phosphine ligands, [(4R,15R)‐,3‐bis(trifluoromethanesulfonyl)perhydro‐1,3,2‐benzodiazaphosphol‐2‐yl]diethylamine, C12H20F6N3O4PS2, (IIIa), [(4R,5R)‐1,3‐bis(trifluoromethanesulfonyl)perhydro‐1,3,2‐benzodiazaphosphol‐2‐yl]dimethylamine, C10H16F6N3O4PS2, (IIIb), and bis[(4R,5R)‐1,3‐bis(trifluoromethanesulfonyl)perhydro‐1,3,2‐benzodiazaphosphol‐2‐yl]methylamine, (IV), as the chloroform solvate, C17H23F12N5O8P2S4·0.98CHCl3, have been prepared from (1R,2R)‐N,N′‐bis(trifluoromethanesulfonyl)‐1,2‐cyclohexanediamine and diethyl phosphoramidous dichloride, dimethyl phosphoramidous dichloride or methyl imidodiphosphorus tetrachloride. The π‐acceptor abilities of these new types of ligands have been evaluated by X‐ray determination of the P—N bond lengths; it has been found that the most promising ligand is the bis(phosphine) (IV). 相似文献
11.
Cara Nygren Tianniu Chen Sanbao Zhong Conrad Kaczmarek John F. C. Turner David C. Baker 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):o208-o210
The structures of two compounds which are intermediates in the synthesis of phenanthroindolizidine alkaloids have been determined. (8bS,13aS,14R,14aR)‐8b,9,11,12,13,13a,14,14a‐Octahydro‐14‐hydroxy‐2,3,6,7‐tetramethoxydibenzo[f,h]pyrrolo[1,2‐b]isoquinolin‐11‐one acetone solvate, C24H27NO6·C3H6O, (II), crystallizes in a chiral space group with one solvent molecule (acetone) present in the asymmetric unit. On the other hand, (8bS,13aS,14S,14aR)‐8b,9,11,12,13,13a,14,14a‐octahydro‐14‐hydroxy‐2,3,6,7‐tetramethoxydibenzo[f,h]pyrrolo[1,2‐b]isoquinolin‐11‐one, C24H27NO6, (III), crystallizes in a centrosymmetric space group with two molecules in the asymmetric unit and with no solvent present. The two molecules in the asymmetric unit of (III) are structurally the same. Compounds (II) and (III) are epimers at the C atom carrying the OH group; otherwise they are very similar in structure. 相似文献
12.
Manuel Hewitt Thomas R. Schneider Zsuzsanna Szemerdi Andrea Hajnal Janos Wlfling Gyula Schneider 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):e363-e364
The structure of methyl (6R)‐6‐(3′β‐acetoxy‐5′‐androsten‐17′β‐yl)‐2‐phenyl‐5,6‐dihydro‐4H‐[1,3]oxazine, C31H41NO3, synthesized from an azidopregnene derivative, is reported. The dihydro‐1,3‐oxazine ring is connected in the β position to the sterane skeleton at C‐17′. An R configuration was found at C‐6. 相似文献
13.
Makoto Eishima Shigeru Ohba Masumi Suzuki Chiaki Nagasawa Takeshi Sugai 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1391-1393
In the racemic crystals of (1S,2R)‐ or (1R,2S)‐1‐[N‐(chloroacetyl)carbamoylamino]‐2,3‐dihydro‐1H‐inden‐2‐yl chloroacetate, C14H14Cl2N2O4, (I), the enantiomeric molecules form a dimeric structure via the N—H?O cyclic hydrogen bond of the carbamoyl moieties. In the chiral crystals of (—)‐(1S,2R)‐1‐[N‐(chloroacetyl)carbamoylamino]‐2,3‐dihydro‐1H‐inden‐2‐yl chloroacetate, C14H14Cl2N2O4, (II), the N—H?O intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis. The melting points and calculated densities of (I) and (II) are 446 and 396 K, and 1.481 and 1.445 Mg m?3, respectively. 相似文献
14.
M. D. Crozet P. Vanelle M. Giorgi A. Gellis 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o496-o498
The title compounds, C13H15N3O5S and C11H10N2O4S2, respectively, both contain a phenylsulfonyl group connected, through a methylene bridge, to either a substituted nitroimidazole or nitro‐1,3‐thiazole ring. In the imidazole‐containing molecule, the nitro and sulfonyl groups are trans relative to the sulfonyl–methyl bond, while in the thiazole‐containing molecule, these substituents are cis. The stabilizing interactions within the crystals are also different between the two compounds. 相似文献
15.
Ivan Leban Lovro Seli
Toma Mesar Anton opar Tom olmajer 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o367-o369
The molecular structure of the title tricyclic compound, C17H21NO4, which is the immediate precursor of a potent synthetic inhibitor {Lek157: sodium (8S,9R)‐10‐[(E)‐ethylidene]‐4‐methoxy‐11‐oxo‐1‐azatricyclo[7.2.0.03,8]undec‐2‐ene‐2‐carboxylate} with remarkable potency, provides experimental evidence for the previously modelled relative position of the fused cyclohexyl ring and the carbonyl group of the β‐lactam ring, which takes part in the formation of the initial tetrahedral acyl–enzyme complex. In this hydrophobic molecule, the overall geometry is influenced by C—H?O intramolecular hydrogen bonds [3.046 (4) and 3.538 (6) Å, with corresponding normalized H?O distances of 2.30 and 2.46 Å], whereas the molecules are interconnected through intermolecular C—H?O hydrogen bonds [3.335 (4)–3.575 (5) Å]. 相似文献
16.
Luz Arancibia Mariana Naspi Graciela Pucci Maricel Rodriguez Florencia Di Salvo 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(9):914-920
The terpenoid (?)‐Istanbulin A is a natural product isolated from Senecio filaginoides DC, one of the 270 species of Senecio (Asteraceae) which occurs in Argentina. The structure and absolute configuration of this compound [9a‐hydroxy‐3,4a,5‐trimethyl‐4a,6,7,8a,9,9a‐hexahydro‐4H,5H‐naphtho[2,3‐b]‐furan‐2,8‐dione or (4S,5R,8R,10S)‐1‐oxo‐8β‐hydroxy‐10βH‐eremophil‐7(11)‐en‐12,8β‐olide, C15H20O4] were determined by single‐crystal X‐ray diffraction studies. It proved to be a sesquiterpene lactone showing an eremophilanolide skeleton whose chirality is described as 4S,5R,8R,10S. Structural results were also in agreement with the one‐ and two‐dimensional (1D and 2D) NMR and HR–ESI–MS data, and other complementary spectroscopic information. In addition, (?)‐Istanbulin A is a polymorph of the previously reported form of (?)‐Istanbulin A, form I; thus, the title compound is denoted form II or polymorph II. Structural data and a literature search allowed the chirality of Istanbulin A to be revisited. The antimicrobial and antifungal activities of (?)‐Istanbulin A, form II, were evaluated in order to establish a reference for future comparisons and applications related to specific crystal forms of Istanbulins. 相似文献
17.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(5):564-570
As part of a project studying the secondary metabolites extracted from the Chilean flora, we report herein three new β‐agarofuran sesquiterpenes, namely (1S,4S,5S,6R,7R,8R,9R,10S)‐6‐acetoxy‐4,9‐dihydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C27H32O11, ( II ), (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepine‐5,10‐diyl bis(furan‐3‐carboxylate), C27H32O10, ( III ), and (1S,4S,5S,6R,7R,9S,10S)‐6‐acetoxy‐10‐(benzoyloxy)‐9‐hydroxy‐2,2,5a,9‐tetramethyloctahydro‐2H‐3,9a‐methanobenzo[b]oxepin‐5‐yl furan‐3‐carboxylate, C29H34O9, ( IV ), obtained from the seeds of Maytenus boaria and closely associated with a recently published relative [Paz et al. (2017). Acta Cryst. C 73 , 451–457]. In the (isomorphic) structures of ( II ) and ( III ), the central decalin system is esterified with an acetate group at site 1 and furoate groups at sites 6 and 9, and differ at site 8, with an OH group in ( II ) and no substituent in ( III ). This position is also unsubstituted in ( IV ), with site 6 being occupied by a benzoate group. The chirality of the skeletons is described as 1S,4S,5S,6R,7R,8R,9R,10S in ( II ) and 1S,4S,5S,6R,7R,9S,10S in ( III ) and ( IV ), matching the chirality suggested by NMR studies. This difference in the chirality sequence among the title structures (in spite of the fact that the three skeletons are absolutely isostructural) is due to the differences in the environment of site 8, i.e. OH in ( II ) and H in ( III ) and ( IV ). This diversity in substitution, in turn, is responsible for the differences in the hydrogen‐bonding schemes, which is discussed. 相似文献
18.
Cocrystallization and configurations of myo‐inositol‐1,2‐l‐camphor acetals in two crystal structures
Graeme J. Gainsford Sylvia M. Baars Andrew Falshaw 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(3):o169-o172
The inositol rings in (1S,2R,3R,4S,5S,6R,7S,8S,11S)‐myo‐inositol‐1,2‐camphor acetal {systematic name: (1R,2S,3S,4R,5S,6R)‐5,6‐[(1S,2S,4S)‐1,7,7‐trimethylbicyclo[2.2.1]heptane‐2,2‐diyldioxy]cyclohexane‐1,2,3,4‐tetrol}, C16H26O6, and (1R,2S,3S,4R,5R,6S,7R/S,8S,11S)‐myo‐inositol‐1,2‐camphor acetal trihydrate {systematic name: (1S,2R,3R,4S,5R,6S)‐5,6‐[(1S,4S,6R/S)‐1,7,7‐trimethylbicyclo[2.2.1]heptane‐2,2‐diyldioxy]cyclohexane‐1,2,3,4‐tetrol trihydrate}, C16H26O6·3H2O, adopt flattened chair conformations with the latter crystal containing two stereoisomers in a 0.684 (2):0.316 (2) ratio, similar to that found both in solution and by calculation. Both molecules pack in the crystals in similar two‐dimensional layers, utilizing strong O—H⋯O hydrogen bonds, with the trihydrate cell expanded to incorporate the additional hydrogen‐bonded water molecules. 相似文献
19.
Alexander J. Blake Binod B. De Wan‐Sheung Li Neil R. Thomas 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):m570-m574
In the title compounds, [N‐(phenyl{2‐[N‐(S)‐(2‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C33H30N4O3)], (I), [N‐(phenyl{2‐[N‐(S)‐(3‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II) hemihydrate, [Ni(C33H30N4O3)]·0.5H2O, (II), and [N‐({2‐[N‐(S)‐ethylprolylamino]phenyl}phenylmethylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C29H29N3O3)], (III), the NiII centres have approximate square‐planar coordination geometries from N3O donor sets. The picolyl N atoms in (I) and (II) are too remote from the metal centres to interact significantly, but the metal coordination geometries experience tetrahedral distortion and/or displacement of the metal centre from the N3O plane. These are linked to conformational differences between the ligands of the symmetry‐independent complexes (Z′ = 2), which in turn are related to molecular packing. In (III), where a less sterically demanding ethyl group replaces the picolyl substituents, there are none of the distortions or displacements seen in (I) and (II). 相似文献