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Charles R. Ojala William H. Ojala Doyle Britton Christopher J. Cramer 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):o518-o523
Three polymorphs of 4,4′‐diiodobenzalazine (systematic name: 4‐iodobenzaldehyde azine), C14H10I2N2, have crystallographically imposed inversion symmetry. 4‐Chloro‐4′‐iodobenzalazine [systematic name: 1‐(4‐chlorobenzylidene)‐2‐(4‐iodobenzylidene)diazane], C14H10ClIN2, has a partially disordered pseudocentrosymmetric packing and is not isostructural with any of the polymorphs of 4,4′‐diiodobenzalazine. All structures pack utilizing halogen–halogen interactions; some also have weak π (benzene ring) interactions. A comparison with previously published methylphenylketalazines (which differ by substitution of methyl for H at the azine C atoms) shows a fundamentally different geometry for these two classes, namely planar for the alazines and twisted for the ketalazines. Density functional theory calculations confirm that the difference is fundamental and not an artifact of packing forces. 相似文献
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Anions of enolized heteroaromatic 1,3‐dicarbonyl systems, such as the title compounds 1, 9,14 , and 19 , react in dimethylformamide in the presence of potassium carbonate with diaryl disulfides 2 to yield arylsulfenyl derivatives ( 3, 10, 15, 20 ). The arylthiolate anions 4 formed in this reaction can be oxidized by air to yield the starting disulfides 2 again. Tetraalkylthiuram disulfides 7 react in the same manner to yield dialkylaminothiocarbonylthio derivatives ( 8, 13, 18 ) of the title compounds. Oxidation of the arylsulfenyl derivatives with hydrogen peroxide in sodium hydroxide solution usually leads to sulfoxides ( 5, 11, 16 ), whereas oxidation with peracetic acid affords sulfones ( 6, 12, 17 ). 相似文献
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Jakub Wojciechowski Henryk Krawczyk Marcin
liwiski Karolina Kafarska Wojciech M. Wolf 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o280-o282
The title compound, C14H20O2, adopts a conformation in which the δ‐valerolactone and cyclohexane rings are almost coplanar with one another. The γ‐methyl substituent occupies an axial position with respect to the cyclohexane ring. The δ‐valerolactone moiety adopts an envelope arrangement, while the cyclohexane ring exists in a chair conformation. 相似文献
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Susanne Flock Clemens Bruhn Heinrich Fink Herbert Frauenrath 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o101-o103
The title enantiomorphic compounds, C16H23NO4S, have been obtained in an enantiomerically pure form by crystallization from a diastereomeric mixture either of (2S,4S)‐ and (2R,4S)‐ or of (2R,4R)‐ and (2S,4R)‐2‐tert‐butyl‐4‐methyl‐3‐(4‐tolylsulfonyl)‐1,3‐oxazolidine‐4‐carbaldehyde. These mixtures were prepared by an aziridination rearrangement process starting with (S)‐ or (R)‐2‐tert‐butyl‐5‐methyl‐4H‐1,3‐dioxine. The crystal structures indicate an envelope conformation of the oxazolidine moiety for both compounds. 相似文献
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Clair Bilton Judith A. K. Howard N. N. Laxmi Madhavi Gautam R. Desiraju Frank H. Allen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1356-1358
The title compounds, C8H10O2, (I), and C12H14O2, (II), occurred as by‐products in the controlled synthesis of a series of bis(gem‐alkynols), prepared as part of an extensive study of synthon formation in simple gem‐alkynol derivatives. The two 4‐(gem‐alkynol)‐1‐ones crystallize in space group P21/c, (I) with Z′ = 1 and (II) with Z′ = 2. Both structures are dominated by O—H?O=C hydrogen bonds, which form simple chains in the cyclohexane derivative, (I), and centrosymmetric dimers, of both symmetry‐independent molecules, in the cyclohexa‐2,5‐diene, (II). These strong synthons are further stabilized by C[triple‐bond]C—H?O=C, Cmethylene—H?O(H) and Cmethyl—H?O(H) interactions. The direct intermolecular interactions between donors and acceptors in the gem‐alkynol group, which characterize the bis(gem‐alkynol) analogues of (I) and (II), are not present in the ketone derivatives studied here. 相似文献
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Liu Jun Li Jun Yang Shaorong Li Hua Hu Quanyuan Xu Hansheng Hu Xianming 《Journal of heterocyclic chemistry》2001,38(2):515-518
(2R,4S,5S)‐(+)‐5‐(2,2‐Dichloroacetamido)‐4‐(4‐nitrophenyl)‐2‐aryl‐1,3‐dioxanes 3–8 were synthesized with high diastereoselectivity and good yields. The structures of acetals were determined and the configurations were confirmed by 2D‐NMR (NOESY) and X‐ray crystallographic analysis. 相似文献
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Christopher S. Frampton David D. MacNicol Derek R. Wilson 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):o188-o191
The title compounds, C18H21NO and C18H21NS, in their enantiomerically pure forms are isostructural with the enantiomerically pure 4‐(4‐hydroxyphenyl)‐2,2,4‐trimethylchroman and 4‐(2,4‐dihydroxyphenyl)‐2,2,4‐trimethylchroman analogues and form extended linear chains via N—H...O or N—H...S hydrogen bonding along the [100] direction. The absolute configuration for both compounds was determined by anomalous dispersion methods with reference to both the Flack parameter and, for the light‐atom compound, Bayesian statistics on Bijvoet differences. 相似文献
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Henryk Krawczyk Marcin
liwiski Wojciech M. Wolf 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o897-o899
The title compound, C11H16O2, adopts a semifolded conformation with the δ‐lactone and cyclohexane rings almost perpendicular to one another. The β‐methyl substituent occupies an axial position with respect to the cyclohexane ring. The δ‐lactone moiety adopts a slightly distorted half‐chair arrangement, while the cyclohexane ring exists in an almost ideal chair conformation. 相似文献
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Jakub Wojciechowski Henryk Krawczyk Marcin
liwiski Wojciech M. Wolf 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):o351-o353
The title compound, C11H16O3, adopts a conformation in which the δ‐valerolactone and cyclohexane rings are almost coplanar with one another. The β‐methoxy substituent occupies an axial position with respect to the cyclohexane ring. The δ‐valerolactone moiety adopts a half‐chair arrangement, while the cyclohexane ring exists in a chair conformation. 相似文献
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S. Sukdolak S. Soluji N. Manojlovi N. Vukovi L. J. Krsti 《Journal of heterocyclic chemistry》2004,41(4):593-596
3‐Acetyl‐4‐hydroxy‐chromen‐2‐one ( 1 ) was brominated with phenyltrimethylammonium tribromide to afford 3‐(2‐bromoacetyl)‐4‐hydroxy‐chromen‐2‐one ( 2 ) whose reactions with thiourea, thioacetamide and ammonium dithiocarbamate gave respectively 3‐(2‐amino‐thiazol‐4‐yl)‐4‐hydroxy‐, 4‐hydroxy‐3‐(2‐phenyl‐thiazol‐4‐yl)‐ and 4‐hydroxy‐3‐(2‐mercapto‐thiazol‐4‐yl)chromen‐2‐one. In a similar manner, com pound 2 was treated with four 1‐substituted‐2‐thioureas and thiobenzamide to give the corresponding 4‐hydroxy‐3‐(thiazol‐4‐yl)‐chromen‐2‐one derivatives. 相似文献