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1.
Hiromitsu Maeda Atsuhiro Osuka Hiroyuki Furuta 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o338-o339
In the title compound, C9H7N3, the allenyl form of the side chain (–CH=C=CH2) is found in preference to the propargyl form (–CH2—C[triple‐bond]CH). The bond distances between the C atoms in the side chain are 1.303 (3) and 1.289 (3) Å. 相似文献
2.
Xiaosong Hu Wenhui Zhang Allen G. Oliver Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(4):o146-o150
Methyl 2‐acetamido‐2‐deoxy‐β‐d ‐glucopyranoside (β‐GlcNAcOCH3), (I), crystallizes from water as a dihydrate, C9H17NO6·H2O, containing two independent molecules [denoted (IA) and (IB)] in the asymmetric unit, whereas the crystal structure of methyl 2‐formamido‐2‐deoxy‐β‐d ‐glucopyranoside (β‐GlcNFmOCH3), (II), C8H15NO6, also obtained from water, is devoid of solvent water molecules. The two molecules of (I) assume distorted 4C1 chair conformations. Values of ϕ for (IA) and (IB) indicate ring distortions towards BC2,C5 and C3,O5B, respectively. By comparison, (II) shows considerably more ring distortion than molecules (IA) and (IB), despite the less bulky N‐acyl side chain. Distortion towards BC2,C5 was observed for (II), similar to the findings for (IA). The amide bond conformation in each of (IA), (IB) and (II) is trans, and the conformation about the C—N bond is anti (C—H is approximately anti to N—H), although the conformation about the latter bond within this group varies by ∼16°. The conformation of the exocyclic hydroxymethyl group was found to be gt in each of (IA), (IB) and (II). Comparison of the X‐ray structures of (I) and (II) with those of other GlcNAc mono‐ and disaccharides shows that GlcNAc aldohexopyranosyl rings can be distorted over a wide range of geometries in the solid state. 相似文献
3.
Paola Barraja Patrizia Diana Antonino Lauria AnnaMaria Almerico Gaetano Dattolo Girolamo Cirrincione 《Helvetica chimica acta》2001,84(8):2212-2219
2‐Diazo‐2H‐indoles were prepared by diazotization of the corresponding 1H‐indol‐2‐amines and subsequent neutralization. On the basis of NMR data and ab initio and semiempirical calculations, we suggest that the zwitterionic form A is the most representative structure for 2‐diazo‐2H‐indoles. In fact, spectral data are compatible with a 1H‐indole structure, and the fully optimized molecules gave distances in agreement with those reported for the anion obtained from 1H‐indole. The calculated charges are compatible with a zwitterionic structure in which the negative charge is mainly located at the ring N‐atom at variance with the case of diazopyrroles and 3‐diazo‐3H‐indoles where the negative charge is essentially located on the ipso C‐atom. 相似文献
4.
David L. Hughes Michael C. McDermott G. Richard Stephenson Andrew J. Walkington 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):o7-o9
The title compound, C14H18INO, crystallizes as +sc/+sp/+sc 2‐iodoanilide molecules (and racemic opposites) and shows significant intermolecular I...O interactions in the solid state, forming dimeric pairs about centres of symmetry. Under asymmetric Heck conditions, the S enantiomer of the dihydroindol‐2‐one was obtained using (R)‐(+)‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl [(R)‐BINAP], suggesting a mechanism that proceeds by oxidative addition to give the title (P) enantiomer of the compound and pro‐S coordination of the Re face of the alkene in a conformation similar to that defined crystallographically, except that rotation about the C—C bond of the butenyl group is required. 相似文献
5.
Marie‐Rose Spirlet Jean F. Desreux Alain Riondel Gilles Herbst Jean Goudiakas 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(10):1258-1259
In the crystal structure of the title compound, C9H14N2O3, the molecules are linked by N—H?O=C bonds into chains parallel to [001]. Large crystals are readily obtained, presumably because of the hydrogen bonds and an energetically stable conformation of the molecule. 相似文献
6.
Lars Meyer Bruno Elsholz Ingo Reulecke Kerstin Schmidt Paul Margaretha Pablo Wessig 《Helvetica chimica acta》2002,85(7):2065-2072
The outcome of the photocycloaddition of cyclohex‐2‐enones to 2‐alkylprop‐2‐enenitriles differs basically from that of the corresponding 2‐alkylbut‐1‐en‐3‐ynes. While the latter afford mainly products resulting from 1,6‐cyclization of the intermediate triplet alkyl‐(prop‐2‐ynyl) 1,4‐biradical, the former give only cyclobutanecarbonitriles resulting from 1,4‐cyclization of the singlet alkyl‐cyanoalkyl 1,4‐biradical. 相似文献
7.
Valery Belakhov Mark Botoshansky Timor Baasov 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):m450-m452
The hexopyranosyl ring of the title compound, [Hg(CH3)(C9H15O7S)], adopts the 4C1 chair conformation, and the anomeric configuration of the thiomethylmercury linkage is β. The compound exists as two symmetry‐independent conformers, A and B, within the unit cell, and each shows an almost linear S—Hg—C arrangement. Most of the bond distances and angles in A and B are similar, although a marked difference exists in the side‐chain conformation. Weak secondary intramolecular (between Hg and ring O) and intermolecular (between A and B conformers) interactions are documented. 相似文献
8.
Vratislav Langer Miroslav Ko Dalma Gyepesov Juraj Kronek Jozef Lusto Mariana Sldkovi
ov 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o602-o606
Crystal structures are reported for three isomeric compounds, namely 2‐(2‐hydroxyphenyl)‐2‐oxazoline, (I), 2‐(3‐hydroxyphenyl)‐2‐oxazoline, (II), and 2‐(4‐hydroxyphenyl)‐2‐oxazoline, (III), all C9H9NO2 [systematic names: 2‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (I), 3‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (II), and 4‐(4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O—H⋯N hydrogen bond. Surprisingly, the 2‐oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2‐oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C—H⋯N hydrogen bonds. In (III), strong intermolecular O—H⋯N hydrogen bonds and weak intramolecular C—H⋯O hydrogen bonds lead to the formation of an infinite chain of molecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions. 相似文献
9.
Alexander D. Vasiliev Alexander M. Astachov Oksana A. Golubtsova Konstantin V. Pekhotin Mark V. Rogozin Ludmila A. Kruglyakova Rudolf S. Stepanov 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1101-1102
The molecule of the title compound, C2H2N6O4, consists of three planar fragments, namely a tetrazole ring, a nitromethyl group and a nitro group. The nitro group and the tetrazole cycle are arranged in the same plane, but the planar nitromethyl group is located nearly orthogonal to this plane. The molecules are packed in the crystal via van der Waals interactions. 相似文献
10.
Guillaume Journot Reinhard Neier Helen Stoeckli‐Evans 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(3):o119-o122
In the title compounds, C11H18N2, (II), and C13H20N2O, (III), the pyrrolidine rings have twist conformations. Compound (II) crystallizes with two independent molecules (A and B) in the asymmetric unit. The mean planes of the pyrrole and pyrrolidine rings are inclined to one another by 89.99 (11) and 89.35 (10)° in molecules A and B, respectively. In (III), the amide derivative of (II), the same dihedral angle is much smaller, at only 13.42 (10)°. In the crystal structure of (II), the individual molecules are linked via N—H...N hydrogen bonds to form inversion dimers, each with an R22(12) graph‐set motif. In the crystal structure of (III), the molecules are linked via N—H...O hydrogen bonds to form inversion dimers with an R22(16) graph‐set motif. 相似文献
11.
Tod J. Miller Yanwen Fu Frank R. Fronczek Robert P. Hammer 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e574-e575
The title compound, C18H19NO4, is the key synthetic intermediate in the preparation of α,α‐dibenzyl‐α‐amino acid (dibenzylglycine, Dbg), the disubstituted homologue of phenylalanine, following the dialkylation of ethyl nitroacetate. The molecule does not have its potential mirror symmetry in the crystal, with the two benzyl groups forming N—C—C—C torsion angles of 60.31 (13) and 79.89 (13)°. 相似文献
12.
Synthesis and Reactivity of 2‐Pyrrolidino‐, 2‐N‐Methylpiperazino‐, 2‐Piperidino‐, and 2‐Morpholino‐1,3,4‐thiadiazines 下载免费PDF全文
Stefanie Knak Wolf‐Diethard Pfeiffer Horst Dollinger Peter Langer 《Journal of heterocyclic chemistry》2015,52(2):450-462
A variety of 2‐pyrrolidino‐, 2‐N‐methylpiperazino‐, 2‐piperidino‐, and 2‐morpholino‐1,3,4‐thiadiazines were prepared by cyclocondensation of phenacyl halides with thiosemicarbazides. Heating of the products resulted in desulfurization and formation of pyrazoles. The rate of this process strongly depends on the substitution pattern of the 1,3,4‐thiadiazines. 相似文献
13.
Joanna Meszko Karol Krzymiski Antoni Konitz Jerzy Baejowski 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o157-o158
The title compound, C22H17NO3, crystallizes in the monoclinic space group P21/c with four molecules per unit cell. The molecules are arranged in centrosymmetric pairs, joined via the C and attached H atoms in the meta position relative to the methoxy group. These pairs are bonded in the crystalline phase as a result of non‐specific dispersive interactions, and through a network of C—H?O interactions involving the non‐bonded O atom of the carboxy group and, to some extent, the O atom of the methoxy group. The methoxy substituent lies in the plane of the almost planar acridine moiety and is directed towards the phenyl ester group. The phenyl ester group itself is twisted by 35.9 (5)° relative to the mean plane of the acridine moiety. 相似文献
14.
2-脱氧-烟酰胺基-β-D-氨基葡萄糖的合成和表征 总被引:1,自引:0,他引:1
A new nicotinic acid derivative,2-deoxy-2-nicotinoylamido-β-D-glucopyranose, was synthesized with β-configuration exclusively. The structure and properties of the product were characterized by ^1H NMR, PT-IR, MS, DSC and polarimeter. The details of ^1H NMR spectrum and the mass spectrum proved that there are a great amount of hydrogen bonds in the product. 相似文献
15.
Martin W. M. Fijten Richard Hoogenboom Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2008,46(14):4804-4816
The aim of this research was to study the effect of the initiator on the resulting monomer distribution for the cationic ring‐opening copolymerization of 2‐ethyl‐2‐oxazoline (EtOx) and 2‐phenyl‐2‐oxazoline (PhOx). At first, kinetic studies were performed for the homopolymerizations of both monomers at 160 °C under microwave irradiation using four initiators. These initiators have the same benzyl‐initiating group but different leaving groups, Cl?, Br?, I?, and OTs?. The basicity of the leaving group affects the ratio of covalent and cationic propagating species and, thus, the polymerization rate. The observed differences in polymerization rates could be correlated to the concentration of cationic species in the polymerization mixture as determined by 1H NMR spectroscopy. In a next‐step, polymerization kinetics were determined for the copolymerizations of EtOx and PhOx with these four initiators. The reactivity ratios for these copolymerizations were calculated from the polymerization rates obtained for the copolymerizations. This approach allows more accurate determination of the copolymerization parameters compared to conventional methods using the composition of single polymers. When benzyl chloride (BCl) was used as an initiator, no copolymers could be obtained because its reactivity is too low for the polymerization of PhOx. With decreasing basicity of the used counterions (Br? > I? > OTs?), the reactivity ratios gradually changed from rEtOx = 10.1 and rPhOx = 0.30 to rEtOx = 7.9 and rPhOx = 0.18. However, the large difference in reactivity ratios will lead to the formation of quasi‐diblock copolymers in all cases. In conclusion, the used initiator does influence the monomer distribution in the copolymers, but for the investigated system the differences were so small that no difference in the resulting polymer properties is expected. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4804–4816, 2008 相似文献
16.
Vijayakumar N. Sonar Sean Parkin Peter A. Crooks 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o527-o530
In the title compounds, C12H12N2O2, (I), and C17H14N2O2, (II), respectively, the indole rings are planar and the vinyl groups lie out of the indole planes, making dihedral angles of 33.48 (5) and 41.31 (8)°, respectively. In (II), the dihedral angle between the phenyl and indole ring planes is 32.06 (6)°. In both molecules, the double bond connecting the methylnitrovinyl group and the indole nucleus adopts an E configuration. Notwithstanding the differences in space group [C2/c for (I) and P212121 for (II)], the mode of packing of compounds (I) and (II) is determined by similar intermolecular N—H⋯O hydrogen‐bonding interactions, forming chains that run parallel to [101] in (I) and [001] in (II). 相似文献
17.
Hanneke M. L. Lambermont‐Thijs Mark J. H. C. Jochems Richard Hoogenboom Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2009,47(23):6433-6440
In this study, the structure–property relationships for a series of statistical 2‐nonyl‐2‐oxazoline (NonOx) and 2‐phenyl‐2‐oxazoline (PhOx) copolymers were investigated for the first time. The copolymerization kinetics were studied and the reactivity ratios were calculated to be rNonOx = 7.1 ± 1.4 and rPhOx = 0.02 ± 0.1 revealing the formation of gradient copolymers. The synthesis of a systematical series of NonOx–PhOx copolymers is described, whereby the amount of NonOx was increased in steps of 10 mol %. The thermal and surface properties were investigated for this series of well‐defined copolymers. The thermal properties revealed a linear decrease in glass transition temperature for copolymers containing up to 39 wt % NonOx. Furthermore, the melting temperature of the copolymers containing 0 to 55 wt % PhOx linearly decreased most likely due to disturbance of the NonOx crystalline domains by incorporation of PhOx in the NonOx part of the copolymer. The surface energies of spincoated polymer films revealed a strong decrease in surface energy upon incorporation of NonOx in the copolymers due to strong phase separation between NonOx and PhOx allowing the NonOx chains to orient to the surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6433–6440, 2009 相似文献
18.
Bin Huang Pei‐Gang Huang Shou‐Ri Sheng Qiu‐Ying Wang Lei Guo Shao‐Hua Jiang 《中国化学会会志》2007,54(3):575-578
An efficient liquid‐phase synthesis of 2‐methyl‐2‐aryloxypropanoic acid derivatives with good yields and high purity on soluble polyethylene glycol (PEG) has been developed by treatment of PEG‐bound 2‐bromo‐2‐methylpropanoate with phenoxides in the presence of a catalytic amount of NBu4I and KI, and subsequent cleavage from the PEG. 相似文献
19.
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
20.
Jose C. J. M. D. S. Menezes Bikshandarkoil R. Srinivasan Pallepogu Raghavaiah Shashikumar K. Paknikar Shrivallabh P. Kamat 《Journal of heterocyclic chemistry》2011,48(4):952-956
Two new structurally isomeric, 2‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[h]chromen‐2‐yl)‐1‐naphthol ( 1 ) and 3‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[g]chromen‐2‐yl)‐2‐naphthol ( 3 ) have been synthesized from 2‐acetyl‐1‐naphthol and ethyl‐3‐hydroxy‐2‐naphthoate, respectively, involving Grignard reaction, dehydration of the corresponding tertiary alcohols, and hetero Diels–Alder dimerization. The two benzochromenes ( 1 and 3 ) have been fully characterized by IR, NMR, and HRESIMS data. Their structures are further supported by crystallography of their corresponding acetates ( 2 and 4 ). J. Heterocyclic Chem., (2011). 相似文献