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1.
Jan ejka Bohumil Kratochvíl Ivana Císaov Alexandr Jegorov 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o428-o430
Simvastatin, or (1S,3R,7S,8S,8aR)‐8‐{2‐[(2R,4R)‐4‐hydroxy‐6‐oxo‐3,4,5,6‐tetrahydro‐2H‐pyran‐2‐yl]ethyl}‐3,7‐dimethyl‐1,2,3,7,8,8a‐hexahydronaphthalen‐1‐yl 2,2‐dimethylbutanoate, C25H38O5, is almost isostructural with lovastatin, and the general conformational features are closely related to those of other reported crystal structures of statins. The only hydrogen bond present facilitates the formation of infinite chains of molecules along the b axis. 相似文献
2.
Jianping Zhao Ilias Muhammad D. Chuck Dunbar Ikhlas A. Khan Nikolaus H. Fischer Frank R. Fronczek 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o195-o198
A low‐temperature structure of ginkgolide A monohydrate, (1R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐dimethylethyl)‐hexahydro‐4,7b‐dihydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione monohydrate, C20H24O9·H2O, obtained from Mo Kα data, is a factor of three more precise than the previous room‐temperature determination. A refinement of the ginkgolide A monohydrate structure with Cu Kα data has allowed the assignment of the absolute configuration of the series of compounds. Ginkgolide C sesquihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11S,11aR)‐3‐(1,1‐dimethylethyl)‐hexahydro‐2,4,7b,11‐tetrahydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione sesquihydrate, C20H24O11·1.5H2O, has two independent diterpene molecules, both of which exhibit intramolecular hydrogen bonding between OH groups. Ginkgolide J dihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)‐3‐(1,1‐dimethylethyl)‐hexahydro‐2,4,7b‐trihydroxy‐8‐methyl‐9H‐1,7a‐epoxymethano‐1H,6aH‐cyclopenta[c]furo[2,3‐b]furo[3′,2′:3,4]cyclopenta[1,2‐d]furan‐5,9,12(4H)‐trione dihydrate, C20H24O10·2H2O, has the same basic skeleton as the other ginkgolides, with its three OH groups having the same configurations as those in ginkgolide C. The conformations of the six five‐membered rings are quite similar across ginkgolides A–C and J, except for the A and F rings of ginkgolide A. 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.
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
5.
Cui Rong Sun Hao Shi Yuan Jiang Pan 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o323-o324
Kamebanin, alternatively called rel‐(?)‐(1R,4R,8S,9R,10S,13S,16R)‐2,8,16‐trihydroxy‐5,5,9‐trimethyl‐14‐methylenetetracyclo[11.2.1.01,10.04,9]hexadecan‐15‐one, C20H30O4, is a natural diterpenoid which has cytotoxic and antibacterial activity. The molecule is composed of three six‐membered rings, which all adopt chair conformations, and one five‐membered ring, which adopts an envelope conformation. The conjugated α‐methylenecyclopentanone ring is the active part in the molecule due to the ring strain. All three hydroxy groups serve as hydrogen‐bond donors and acceptors, forming a continuous two‐dimensional network. 相似文献
6.
Smriti Khera Michael D. Carducci Jian‐Qiao Gu Barbara N. Timmermann 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):o773-o775
The structure of an iridolactone isolated from Valeriana laxiflora was established as (4R,4aR,6S,7S,7aS)‐6‐hydroxy‐7‐hydroxymethyl‐4‐methylperhydrocyclopenta[c]pyran‐1‐one chloroform solvate, C10H16O4·CHCl3. The two rings are cis‐fused. The δ‐lactone ring adopts a slightly twisted half‐chair conformation with approximate planarity of the lactone group and the cyclopentane ring adopts an envelope conformation. The hydroxy group, the hydroxymethyl group and the methyl group all have β orientations. The absolute configuration was determined using anomalous dispersion data enhanced by the adventitious inclusion of a chloroform solvent molecule. Hydrogen bonding, crystal packing and ring conformations are discussed in detail. 相似文献
7.
R. Malathi S. S. Rajan G. Suresh G. N. Krishnakumari G. Gopalakrishnan 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o416-o418
Samaderin B, or (1R,2S,5R,5aR,7aS,11S,11aS,11bR,14S)‐1,7,7a,11,11a,11b‐hexahydro‐1,11‐dihydroxy‐8,11a,14‐trimethyl‐2H‐5a,2,5‐(methanoxymetheno)naphth[1,2‐d]oxepine‐4,6,10(5H)‐trione, C19H22O7, and samaderin C, or (1R,2S,5R,5aR,7aS,10S,11S,11aS,11bR,14S)‐7,7a,10,11,11a,11b‐hexahydro‐1,10,11‐trihydroxy‐8,11a,14‐trimethyl‐2H‐5a,2,5‐(methanoxymetheno)naphth[1,2‐d]oxepine‐4,6(1H,5H)‐dione, C19H24O7, were isolated from the seed kernels of Samadera indica and were shown to exhibit antifeedant activity against Spodoptera litura third‐instar larvae. The replacement of the carbonyl group in samaderin B by a hydroxy group in samaderin C causes conformational changes at the substitution site, but the overall conformation is not affected; however, the compounds pack differently in the crystal lattice. 相似文献
8.
Anthony Linden Ihsan alis Markus Neuburger Otto Sticher 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):616-618
The title compound, [2aS‐(2aα,4aα,5α,7bα)]‐5‐(β‐d ‐glucopyranosyloxy)‐2a,4a,5,7b‐tetrahydro‐1‐oxo‐1H‐2,6‐dioxacyclopent[cd]inden‐4‐ylmethyl acetate monohydrate, C18H22O11·H2O, was extracted from the Turkish plant Putoria calabrica (L. fil.) DC. The three fused rings have envelope or distorted envelope conformations and form a bowl in which ring strain causes distortion of some bond angles and significant pyramidalization of two of the Csp2 atoms. The ring junction H atoms are all cis to one another and the glycosidic linkage is in the β axial position. The structure incorporates two symmetry‐independent water molecules, each of which is located on a twofold axis. Intermolecular hydrogen bonds involving all the hydroxy groups and water molecules link the molecules into a complex three‐dimensional framework. 相似文献
9.
William Clegg Simon J. Teat 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1343-1345
The title compound, [(4S,4aS,5aS,6S,12aS)‐2‐aminohydroxymethylene‐1,2,3,4,4a,5,5a,6,11,12a‐decahydro‐6,10,12,12a‐tetrahydroxy‐6‐methyl‐1,3,11‐trioxonaphthacen‐4‐yl]dimethylammonium chloride, C22H25N2O8+·Cl?, a well known antibiotic, has been structurally characterized from an individual coarse powder grain by use of high‐intensity synchrotron radiation, in conjunction with an exercise in ab initio powder diffraction structure solution. Free refinement of all H atoms establishes the major tautomeric form of the protonated tetracycline molecule without prejudice. The molecule has extensive intramolecular hydrogen bonding involving most of the potential donors and acceptors, and all intermolecular hydrogen bonding uses the chloride anion as acceptor. 相似文献
10.
Ademir F. Morel Wellington de A. Gonzaga Robert A. Burrow Ccilia Maichle‐Mssmer Joachim Strhle 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o606-o607
The title compound, 1‐(5‐methyl‐5,6‐dihydro[1,3]dioxolo[4′,5′:4,5]benzo[c][1,5]dioxolo[4,5‐j]phenanthridin‐6‐yl)acetone, C23H19NO5, isolated from the stem bark of Zanthoxylum rhoifolium, crystallizes as a racemate in space group P. The structure shows two aromatic ring systems, each terminated by a five‐membered dioxole ring, coupled by an N‐containing ring. The core of the molecule is almost planar; the planes of the two ring systems form an angle of 18.42 (6)°. The packing shows the molecules parallel to each other and about 3.5 Å apart with graphite‐type interactions. The N‐methyl and acetone groups, which are anti with respect to one another, lie out of the plane and pack in spaces between neighbouring molecules. 相似文献
11.
Anne M. Sauer Frank R. Fronczek Betty C. R. Zhu William E. Crowe Gregg Henderson Roger A. Laine 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(5):o254-o256
Nootkatone, or (4R,4aS,6R)‐4,4a,5,6,7,8‐hexahydro‐4,4a‐dimethyl‐6‐(1‐methylethenyl)naphthalen‐2(3H)‐one, C15H22O, a sesquiterpene with strong repellent properties against Formosan subterranean termites and other insects, has the valencene skeleton. The dibromo derivative (1S,3R,4S,4aS,6R,8aR)‐1,3‐dibromo‐6‐isopropyl‐4,4a‐dimethyl‐1,2,3,4,5,6,7,8‐octahydronaphthalen‐2‐one, C15H24Br2O, has two independent molecules in the asymmetric unit, which differ in the rotation of the isopropyl group with respect to the main skeleton. The C—Br distances are in the range 1.950 (4)–1.960 (4) Å. Both independent molecules form zigzag chains, with very short intermolecular carbonyl–carbonyl interactions, having the perpendicular motif and O⋯C distances of 2.886 (6) and 2.898 (6) Å. These chains are flanked by intermolecular Br⋯Br interactions of distances in the range 4.067 (1)–4.218 (1) Å. The absolute configuration of the dibromo derivative was determined, from which that of nootkatone was inferred. 相似文献
12.
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
13.
Andrzej Gzella Maria D. Rozwadowska 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):981-982
The absolute configuration of the title compound, alternatively called (+)‐(4,5‐dihydro‐2,5‐diphenyloxazol‐4‐yl)methanol, C16H15NO2, has been confirmed as 4S,5S. The hydroxymethyl group and phenyl ring at the asymmetric C atoms exhibit β and α orientations, respectively. The exocyclic C—C bonds at the asymmetric C atoms are mutually anticlinal (?ac). The hydroxyl group and the N atom of the oxazoline ring are involved in an intermolecular hydrogen bond leading to chains of molecules. 相似文献
14.
Richard C. Cambie Clifton E. F. Rickard P. Stewart Rutledge Keri D. Wellington 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):958-960
The sponge Hamigera tarangaensis has yielded eight new compounds and we report here the structure of one of these compounds, hamigeran A, C20H25BrO5, or methyl 7‐bromo‐4β,6‐dihydroxy‐1β‐isopropyl‐3aα,8‐dimethyl‐5‐oxo‐1a,3a,4,5‐tetrahydrocyclopenta[a]naphthalene‐4‐carboxylate, and the decomposition product of hamigeran D, C21H28BrNO4, namely 2‐(8‐bromo‐2β,7‐dimethyl‐4‐oxo‐1,3α‐benzoxazan‐5‐yl)‐3‐isopropylcyclopentylacetic acid. 相似文献
15.
Andrew Hempel Norman Camerman Donald Mastropaolo Arthur Camerman 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1225-1227
The crystal structure of the title compound contains four 2,4‐diamino‐5‐methyl‐6‐[(3,4,5‐trimethoxyanilino)methyl]quinazoline molecules, two dimethyl sulfoxide molecules and three water molecules in the asymmetric unit, i.e. 4C19H23N5O3·2C2H6OS·3H2O. All four quinazoline molecules adopt trans,gauche conformations. An extensive hydrogen‐bond network involving N?N base‐pairing interactions, as well as the dimethyl sulfoxide and water molecules, stabilizes the crystal structure. 相似文献
16.
Dmitrii S. Yufit Judith A. K. Howard 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o141-o143
The crystal structures of (1R,1′S)‐2′,2′‐dichloro‐N‐(1‐phenylethyl)cyclopropane‐1′‐carboxamide, C12H13Cl2NO, (I), and (1R,1′R)‐2′,2′‐difluoro‐N‐(1‐phenylethyl)cyclopropane‐1′‐carboxamide, C12H13F2NO, (II), have been determined. Both crystals contain two independent molecules with different conformations of the phenylethyl groups. In the crystals of both compounds, the molecules are linked together by N—H⃛O hydrogen bonds, thus forming chains in the a direction. 相似文献
17.
John Nicolson Low Justo Cobo Braulio Insuasty Henry Insuasty Manuel Nogueras Adolfo Snchez 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):o103-o105
In both title compounds, i.e. 3‐methyl‐1,5‐diphenyl‐1,6,7,8‐tetrahydropyrazolo[3,4‐b][1,4]diazepine, C19H18N4, (I), and 5‐(4‐chlorophenyl)‐3‐methyl‐1‐phenyl‐1,6,7,8‐tetrahydropyrazolo[3,4‐b][1,4]diazepine, C19H17ClN4, (II), an N—H?N hydrogen bond links six molecules to form an R(30) ring. Compound (I) crystallizes in the R space group and (II) crystallizes in P with three molecules in the asymmetric unit. The molecule of (I) contains a disordered seven‐membered ring. 相似文献
18.
Kinga Suwiska Boenna Golankiewicz Wojciech Zielenkiewicz 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):767-769
The biologically important molecule tricyclic acyclovir, presented here as 3‐[(2‐hydroxyethoxy)methyl]‐6‐methyl‐3H‐imidazolo[1,2‐a]purin‐9(5H)‐one dihydrate, C11H13N5O3·2H2O, shows conformational flexibility, which is observed in the solid state as two symmetrically independent molecules with different side‐chain conformations. Additionally, one of these molecules exhibits side‐chain disorder, such that there are three different conformations in the crystal. Water molecules found in the crystal form (H2O)8 clusters which are located between molecules of tricyclic acyclovir. The complex hydrogen‐bond network formed between water and tricyclic acyclovir in the solid state may be related to the solvation of the molecules in solution. 相似文献
19.
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
20.
Andrew Hempel Norman Camerman Donald Mastropaolo Arthur Camerman 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1048-1049
In the title compound, dimethyl({5‐[2‐(1‐methylamino‐2‐nitroethenylamino)ethylthiomethyl]‐2‐furyl}methyl)ammonium chloride, C13H23N4O3S+·Cl?, protonation occurs at the dimethylamino N atom. The ranitidine molecule adopts an eclipsed conformation. Bond lengths indicate extensive electron delocalization in the N,N′‐dimethyl‐2‐nitro‐1,1‐ethenediamine system of the molecule. The nitro and methylamino groups are trans across the side chain C=C double bond, while the ethylamino and nitro groups are cis. The Cl? ions link molecules through hydrogen bonds. 相似文献