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1.
Elbieta Jankowska Mirosaw Gilski Mariusz Jasklski Zbigniew Grzonka Leszek ankiewicz 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o353-o354
The crystal structure of the title compound, alternatively called 3‐[4‐(benzyloxy)phenyl]‐2‐(N‐tert‐butoxycarbonyl‐N‐methylamino)propionic acid, C22H27NO5, has been studied in order to examine the role of N‐methylation as a determinant of peptide conformation. The conformation of the tert‐butoxycarbonyl group is trans–trans. The side chain has a folded conformation and the two phenyl rings are effectively perpendicular to one another. The carboxylate hydroxyl group and the urethane carbonyl group form a strong intermolecular O—H?O hydrogen bond. 相似文献
2.
Vladimir N. Nesterov David J. Wiedenfeld Svitlana V. Nesterova Lucas F. Hastings 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):o705-o708
The syntheses, X‐ray structural investigations and calculations of the conformational preferences of the carbonyl substituent with respect to the pyran ring have been carried out for the two title compounds, viz. C15H14N2O2, (II), and C20H16N2O2·C2H3N, (III), respectively. In both molecules, the heterocyclic ring adopts a flattened boat conformation. In (II), the carbonyl group and a double bond of the heterocyclic ring are syn, but in (III) they are anti. The carbonyl group forms a short contact with a methyl group H atom in (II). The dihedral angles between the pseudo‐axial phenyl substituent and the flat part of the pyran ring are 92.7 (1) and 93.2 (1)° in (II) and (III), respectively. In the crystal structure of (II), intermolecular N—H⋯N and N—H⋯O hydrogen bonds link the molecules into a sheet along the (103) plane, while in (III), they link the molecules into ribbons along the a axis. 相似文献
3.
Anthony Linden C. Kuan Lee A. S. Muhammad Sofian 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1098-1100
At 160 K, the glucopyranosyl ring of the title compound, C20H28ClIO13, has a near‐ideal 4C1 conformation and the fructofuranosyl ring has a twist 4T3 conformation. The two hydroxy groups are involved in intra‐ and intermolecular hydrogen bonds, with the latter interactions linking the molecules into infinite one‐dimensional chains. The absolute configuration of the molecule has been determined. 相似文献
4.
Vladimir N. Nesterov Elena A. Viltchinskaia 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):616-618
The structures of the title compounds, C15H13N3O4, (I), and C16H15N3O5 [IUPAC name: ethyl 6‐amino‐5‐cyano‐2‐methyl‐4‐(3‐nitrophenyl)‐4H‐pyrano‐3‐carboxylate], (II), are very similar, with the heterocyclic rings adopting boat conformations. The pseudo‐axial m‐nitrophenyl substituents are rotated by 84.0 (1) and 98.7 (1)° in (I) and (II), respectively, with respect to the four coplanar atoms of the boat. The dihedral angles between the phenyl rings and nitro groups are 12.1 (2) and 8.4 (2)° in (I) and (II), respectively. The two compounds have similar patterns of intermolecular N—H?O and N—H?N hydrogen bonding, which link molecules into infinite tapes along b . 相似文献
5.
S. V. Shishkina O. V. Shishkin I. V. Ukrainets N. A. Jaradat O. V. Gorokhova 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e168-e169
The two bicyclic fragments of the title compound, C22H20N4O4, are individually planar and are turned with respect to each other by 77.8 (2)°. The formation of intramolecular O—H?O and N—H?O hydrogen bonds causes considerable changes in the bond lengths within the amidopyridine fragment. 相似文献
6.
Mohammed Sydia Mohamed Said Ould Bahia Djerrari M'Barek El Abbassi Jilali Fifani El‐Mokhtar Essassi Brahim El‐Bali Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e165-e166
The title compound, C14H16N2O2, contains a diazepine ring, which appears in a boat conformation. An intramolecular hydrogen bond is formed between the NH group of the diazepine ring and a carbonyl O atom of one of the side chains. 相似文献
7.
Thanikasalam Kanagasabapathy Panchanatheswaran Krishnaswamy Jeyaraman Ramasubbu 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(11):o579-o582
rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C26H27NOS, (I), and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C13H17NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven‐membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist‐boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist‐boat conformations. The supramolecular architectures are significantly different, depending in (I) on C—H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic π–π stacking interaction. 相似文献
8.
Hans Joachim Breunig Enno Lork Ovidiu Moldovan Ciprian I. Ra? 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(12):m548-m549
The structure of the title compound, alternatively called bis(μ‐tetramethyldistibinediyl)bis(tetracarbonylchromium), [Cr2Sb4(CH3)8(CO)8], consists of two Me4Sb2 bridging units between Cr(CO)4 complex fragments. The centre of the molecule is located on a special position of 2/m symmetry. This is the first characterized Sb4Cr2 heterocycle. 相似文献
9.
Andreas Fischer Daniel Stern Andrea Thorn Sascha Abraham Dietmar Stalke Uwe Klingebiel Prof. Dr. 《无机化学与普通化学杂志》2010,636(8):1527-1532
The lithium salt (HC–NCMe3)2SiFNLiR ( 1 ) R = C6H3(2,6‐CHMe2)2 reacts with trichlorogallium under displacement of the lithium ion by GaCl3 to give the adduct [(HC–NCMe3)2SiFN]– [(GaCl3)R·Li(thf)4]+ ( 1 ). Compound 1 thermally loses LiCl and forms the bicyclic ring intermediates V and VI . Compound VI adds the aniline H2NC6H3(2,6‐CHMe2)2 and the unsaturated, seven‐membered ring compound –NCMe3–CH2–CH=NCMe3GaCl2–NR–SiFNHR– ( 2 ) is obtained. The addition is accompanied by an enamine‐imine‐tautomerism and proves the Lewis acid character of the silicon atom in an unknown 3‐center‐2‐electron interaction of one nitrogen atom with the silicon and gallium atoms. Quantum chemical calculations of the thermal isomerisation process and crystal structures of 1 and 2 are reported. 相似文献
10.
Fatima Al‐Omran Nouria Al‐Awadl Osama Yousef Mohamed Hilmy Elnagdi 《Journal of heterocyclic chemistry》2000,37(1):167-170
Condensation of 1‐arylhydrazono‐1‐benzotriazol‐1‐yl 2‐propanones ( 5a‐c ) with DMF DMA afforded 1‐aryl‐3‐benzotriazol‐1‐yl‐1,4‐dihydropyridazine‐4‐ones ( 8a‐c ). While condensation of 1‐functionally substituted methylbenzotriazoles 3b,c with 2‐arylhydrazono‐3‐oxoarylpropanal 13a,b give 3‐aroyl‐5‐(benzo‐triazolyl‐1‐yl)‐1,6‐dihydro‐1‐phenylpyridazine‐6‐ones and 6‐imines 14a‐d. 相似文献
11.
Synthesis of 1‐Amino‐5,6‐diaryl‐3‐cyano‐1H‐pyridin‐2‐ones and 6,7‐Diaryl‐4‐cyano‐3‐hydroxy‐1H‐[1,2]diazepines from Isoflavones 下载免费PDF全文
Mu‐Lin Zhu Zun‐Ting Zhang Dong Xue Hui‐Liang Hua Yong Liang Stanislaw F. Wnuk 《Helvetica chimica acta》2014,97(4):561-568
The one‐step cyclocondensation of substituted isoflavones (=3‐phenyl‐4H‐1‐benzopyran‐4‐ones) with cyanoacetohydrazide in the presence of KOH afforded a mixture of 1‐amino‐5,6‐diaryl‐3‐cyano‐1H‐2‐pyridin‐2‐ones and 6,7‐diaryl‐4‐cyano‐3‐hydroxy‐1H‐[1,2]diazepines. 相似文献
12.
Tian‐Zhu Zhang Chun‐Yan Wei Guo‐Hai Xu Se‐Won Park 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):o86-o88
The title compound, daphnoretin, C19H12O7, was isolated from the leaves of Stellera chamaejasme L. Two independent molecules are present in the asymmetric unit, with similar conformations. Each of the independent molecules is composed of two chromene systems connected by an ether bridge. The dihedral angles between the mean planes of the two chromene systems are 86.9 (2) and 81.9 (3)°. Molecules form chains via hydrogen bonds and adjacent chains are parallel to each other. 相似文献
13.
Katarzyna
lepokura Monika Gawowska 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o25-o28
The title amidino‐amino acids (a‐Hpro), C6H11N3O3·H2O, (I), and a‐Met, C6H13N3O2S·H2O, (II), respectively, exist in the form of zwitterions. The five‐membered pyrrolidine ring in (I) adopts an envelope conformation, with the Cγ atom out of the plane defined by the rest of the ring atoms, and with the hydroxyl and carboxylate groups in a trans configuration relative to the ring plane. The two crystallographically independent zwitterions in (II) reveal quite different conformations of their side chains and a slightly different orientation of the guanidine moiety with respect to the carboxylate group. The crystal structures of both (I) and (II) are stabilized by extensive networks of O—H·O, N—H·O and C—H·O hydrogen bonds, the network being three‐dimensional in (I) and two‐dimensional in (II). 相似文献
14.
4‐Ethoxycarbonyl‐5‐phenyl‐2,3‐dihydrofuran‐2,3‐dione 1 reacts with aldehydes via the acylketene intermediate 2 giving the 1,3‐dioxin‐4‐ones 3a‐e and the 1,4‐bis(5‐ethoxycarbonyl‐4‐oxo‐6‐phenyl‐4H‐1,3‐dioxin‐2‐yl)benzene 4 , and a one step reaction between dibenzoylmethane and oxalylchloride gave 3,5‐dibenzoyl‐2,6‐diphenyl‐4‐pyrone 7 . The reaction of 1 with dibenzoylmethane, a dicarbonyl compound, provided ethyl 3‐benzoyl‐4‐oxo‐2,6‐diphenylpyran‐5‐carboxylate derivative 9 . Compound 9 was converted into the corresponding ethyl 3‐benzoyl‐4‐hydroxy‐2,6‐diphenylpyridine‐5‐carboxylate derivative 10 via its reaction with ammonium hydroxyde solution in 1 ‐butanol. 相似文献
15.
Ahmed Abu‐Rayyan Dr. Qutaiba Abu‐Salem Norbert Kuhn Prof. Dr. Cäcilia Maichle‐Mößmer Manfred Steimann Gerald Henkel 《无机化学与普通化学杂志》2008,634(5):823-824
On the Hydrolysis of 2,3‐Dihydro‐1,3‐di‐tert‐butyl‐4,5‐dimethylimidazol‐2‐ylidene. The Crystal Structure of 1,3‐Di‐tert‐butyl‐4,5‐dimethylimidazolium Bicarbonate 1,3‐Di‐tert‐butyl‐4,5‐dimethylimidazolium bicarbonate ( 7 ), formed on the exposure of 2,3‐dihydro‐1,3‐di‐tert‐butyl‐4,5‐dimethylimidazol‐2‐ylidene ( 6 ) towards air, is prepared on the reaction of 6 with ammonium bicarbonate; its crystal structure analysis reveals the presence of dimeric bicarbonate anions linked to each other and to the imidazolium ions with hydrogen bonds. 相似文献
16.
Graeme J. Gainsford Cornelis Lensink Andrew Falshaw 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):o650-o652
The novel title compound, C25H31O6P, contains rigid fused rings which are shown to be similar to the precursor structures. Weak C—H⋯O intermolecular interactions produce two‐dimensional sheets composed of R44(28) rings. 相似文献
17.
Glen W. Spears Kiyoshi Tsuji Takashi Tojo Hiroaki Nishimura Takashi Ogino 《Journal of heterocyclic chemistry》2002,39(4):799-804
The novel title compounds have been prepared in high yield by an optimized amide coupling followed by a Dieckmann cyclization. Additionally, this new route is amenable to preparative scale synthesis. 相似文献
18.
Jana Sopkov‐de Oliveira Santos Anna Caruso Jean‐Franois Lohier Jean‐Charles Lancelot Sylvain Rault 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(8):o453-o455
The title carbazolyl boronic ester, C22H28BNO2, (I), is a building block for the synthesis of new carbazole derivatives of potential utility as pharmaceutically active compounds. The crystal structure of (I) and of the title bromocarbazole compound, C16H16BrN, (II), the synthetic precursor of (I), were solved and analysed with the aim of understanding the lack of reactivity of (I) under Suzuki cross‐coupling reaction conditions. In both structures, the methyl groups are coplanar with the carbazole ring system, and the ethyl group lies out of the carbazole plane. The dioxaborolane ring of boronic ester (I) adopts a half‐chair conformation but lies approximately in a planar orientation with respect of the carbazole ring system, whereas the Br atom of (II) is coplanar with the carbazole plane. In (I), the carbazole–boronic ester C—B bond length is 1.5435 (14) Å, which is somewhat shorter than the usual value of 1.57 Å. 相似文献
19.
20.
Heng‐Shan Dong Yan‐Fei Wang Guo‐Liang Shen Bin Quan Wang‐Jun Dong 《Journal of heterocyclic chemistry》2012,49(1):149-153
Some new compounds (E)‐3‐aryl‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐prop‐2‐en‐1‐ones 5a–e were prepared by 1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐ethanone and various aromatic aldehydes. Then one pot reaction was happened by compounds 5a–e with hydrazine hydrate in acetic acid or propionic acid, respectively, to give the title compounds 1acyl‐5‐aryl‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐4,5‐dihydro‐1H‐pyrazoles 6a–i . All structures were established by MS, IR, CHN, 1H‐NMR and 13C‐NMR spectral data. J. Heterocyclic Chem., (2012). 相似文献