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1.
Nalivela Venu Peddy Vishweshwar Thaimattam Ram Devarakonda Surya Bhattacharya Apurba 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o306-o308
The title compound, C8H17NO2, exists as a zwitterion, adopting a propeller conformation. Molecules self‐assemble to form a hydrogen‐bonded layer parallel to the ab crystallographic plane connected by N+—H...O− and C—H...O− hydrogen bonds. These layers are stacked along the c axis and are stabilized by van der Waals interactions. 相似文献
2.
Martin Lutz Jan van Krieken 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(8):o401-o405
The dimeric condensation product of lactic acid, namely (S,S)‐2‐[(2‐hydroxypropanoyl)oxy]propanoic acid, C6H10O5, (I), crystallizes with two independent molecules in the asymmetric unit, which both have an essentially planar backbone. The trimeric condensation product, namely (S,S,S)‐3‐hydroxybut‐3‐en‐2‐yl 2‐[(2‐hydroxypropanoyl)oxy]propanoate, C9H14O7, (II), has one molecule in the asymmetric unit and consists of two essentially planar parts, with the central C—O bond in a gauche conformation. Both molecules of the dimer are involved in intermolecular hydrogen bonds, forming chains with a C(8) graph set. These chains are connected by D(2) hydrogen bonds to form a two‐dimensional layer. The trimer forms hydrogen‐bonded C(10) and C22(6) chains, which together result in a two‐dimensional motif. The Hooft method [Hooft, Straver & Spek (2008). J. Appl. Cryst. 41 , 96–103] was successfully applied to the determination of the absolute structure of (I). 相似文献
3.
Zi‐Qiang Hu Duan‐Jun Xu Yuan‐Zhi Xu Jing‐Yun Wu Michael Y. Chiang 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o612-o614
Crystals of the title complex, C3H7NO2·C8H8O3·0.5H2O, were obtained from an aqueous solution containing racemic mandelic acid and (S)‐alanine. The unit cell includes two independent molecular complexes and one water molecule. The structure formed by (R)‐mandelic acid and (S)‐alanine in a 1:1 molar ratio shows the successful optical separation of racemic mandelic acid. Strong hydrogen bonding, with a rather short O?O separation of 2.494 (3) Å, is observed between the carboxyl and carboxylate groups. A structural comparison suggests that the strong hydrogen bonding affects the neighbouring covalent bond. 相似文献
4.
Ove Alexander Hgmoen strand Zeshan Iqbal Marcel Sandberg Eili T. Kase Carl Henrik Grbitz Pl Rongved 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(6):647-650
(2S,3S)‐2,6‐Dimethylheptane‐1,3‐diol, C9H20O2, (I), was synthesized from the ketone (R)‐4‐benzyl‐3‐[(2R,3S)‐3‐hydroxy‐2,6‐dimethylheptanoyl]‐1,3‐oxazolidin‐2‐one, C19H27NO4, (II), containing C atoms of known chirality. In both structures, strong hydrogen bonds between the hydroxy groups form tape motifs. The contribution from weaker C—H...O hydrogen bonds is much more evident in the structure of (II), which furthermore contains an example of a direct short Osp3...Csp2 contact that represents a usually unrecognized type of intermolecular interaction. 相似文献
5.
Maria Gdaniec Elbieta Nowak Maria J. Milewska Tadeusz Pooski 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o661-o662
The molecule of the title compound, C8H11NO2, contains a strained bicyclic system with a significantly twisted imide chromophore. The five‐membered ring fragment containing the imide function is strongly puckered and adopts a half‐chair conformation. The six‐membered ring has a slightly distorted chair conformation. The molecules are joined by strong N—H?O and weak C—H?O hydrogen bonds into infinite chains. 相似文献
6.
Gerzon E. Delgado Asilo J. Mora Jorge Uzctegui Ali Bahsas Alexander Briceo 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(8):o448-o450
The crystal structure of the title compound, C10H10N2O2·H2O, also known as l ‐5‐benzylhydantoin monohydrate, is described in terms of two‐dimensional supramolecular arrays built up from infinite chains assembled via N—H...O and O—H...O hydrogen bonds among the organic molecules and solvent water molecules, with graph‐set R33(10)C(5)C22(6). The hydrogen‐bond network is reinforced by stacking of the layers through C—H...π interactions. 相似文献
7.
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
8.
Stereoselective Total Synthesis of (3S,5S)‐1,7‐Bis(4‐hydroxyphenyl)heptane‐3,5‐diol, (3S,5S)‐Alpinikatin,and Its Diastereoisomers
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Kunuru Venkatesham Sudina Purushotham Reddy Baggu Chinnababu Katragadda Suresh Babu 《Helvetica chimica acta》2015,98(9):1307-1314
Stereoselective synthesis of the diarylheptanoids, (3S,5S)‐1,7‐bis(4‐hydroxyphenyl)heptane‐3,5‐diol ( 1 ), (3S,5S)‐alpinikatin ( 3 ), and their diastereoisomers ( 2 and 4 , resp.), was achieved from readily available 4‐hydroxybenzaldehyde. The synthetic sequences involve Browns's allylation and Et2Zn mediated diastereoselective alkynylation reaction as key steps. 相似文献
9.
Luis E. Seijas Gerzon E. Delgado Asilo J. Mora Ali Bahsas Alexander Briceo 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o303-o305
In the title compound, also known as N‐carbamoyl‐l ‐proline, C6H10N2O3, the pyrrolidine ring adopts a half‐chair conformation, whereas the carboxyl group and the mean plane of the ureide group form an angle of 80.1 (2)°. Molecules are joined by N—H...O and O—H...O hydrogen bonds into cyclic structures with graph‐set R22(8), forming chains in the b‐axis direction that are further connected via N—H...O hydrogen bonds into a three‐dimensional network. 相似文献
10.
Marko kof Jurij Svete Branko Stanovnik Simona Goli
‐Grdadolnik 《Helvetica chimica acta》2000,83(4):760-766
(3E,5S)‐1‐Benzoyl‐5‐[(benzoyloxy)methyl]‐3‐[(dimethylamino)methylidene]pyrrolidin‐2‐one ( 9 ) was prepared in two steps from commercially available (S)‐5‐(hydroxymethyl)pyrrolidin‐2‐one ( 7 ) (Scheme 1). Compound 9 gave, in one step, upon treatment with various C,N‐ and C,O‐1,3‐dinucleophiles 10 – 18 , the corresponding 3‐(quinolizin‐3‐yl)‐ and 3‐(2‐oxo‐2H‐pyran‐3‐yl)‐substituted (2S)‐2‐(benzoylamino)propyl benzoates 19 – 27 (Schemes 1 and 2). 相似文献
11.
Wei‐Wei Fu Man‐Sheng Chen Yang Liu Fu‐Xing Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(4):384-387
The title compound, (C6H9N2S)[ZnCl3{SC(NH2)2}], exists as a zincate where the zinc(II) centre is coordinated by three chloride ligands and a thiourea ligand to form the anion. The organic cation adopts the protonated 4,6‐dimethyl‐2‐sulfanylidenepyrimidin‐1‐ium (L) form of 4,6‐dimethylpyrimidine‐2(1H)‐thione. Two short N—H...Cl hydrogen bonds involving the pyrimidine H atoms and the [ZnCl3L]− anion form a crystallographically centrosymmetric dimeric unit consisting of two anions and two cations. The packing structure is completed by longer‐range hydrogen bonds donated by the thiourea NH2 groups to chloride ligand hydrogen‐bond acceptors. 相似文献
12.
Udo Beckmann Sally Brooker 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):o653-o655
The structure of the cocrystallized 1:1 adduct of (S,S)‐4‐amino‐3,5‐bis(1‐hydroxyethyl)‐1,2,4‐triazole and (S,S)‐1,2‐bis(2‐hydroxypropionyl)hydrazine, C6H12N4O2·C6H12N2O4, has tetragonal symmetry. All eight O‐ and N‐bound H atoms are involved in intermolecular hydrogen bonds, resulting in infinite zigzag chains of the triazole molecules, with the hydrazine molecules filling the gaps between the chains and completing a three‐dimensional hydrogen‐bonded array. 相似文献
13.
Darwin P. R. Kint Emilia Wigstrm Antxon Martínez de Ilarduya Abdelilah Alla Sebastin Muoz‐Guerra 《Journal of polymer science. Part A, Polymer chemistry》2001,39(19):3250-3262
Novel poly(ethylene terephthalate) (PET) copolyesters, abbreviated PEDMBT, containing optically active (2S,3S)‐2,3‐dimethoxy‐1,4‐butanediol (DMBD) as the second comonomer were investigated. Copolymers with ethylene glycol to DMBD ratios between 95/5 and 50/50 as well as the two parent homopolymers, PET and PDMBT, were prepared by a two‐step melt polycondensation. The resulting copolymers were found to approximately have the composition of the polymerization reaction feed and a random microstructure. Polymer intrinsic viscosities varied from 0.4 to 0.6 dL g?1 with weight‐average molecular weights ranging from 16,000 to 44,000. PEDMBT copolyesters were distinguished in being much more soluble than PET and showing an increasing affinity for water with the content in dimethoxy groups. According to the asymmetric constitution of DMBD, they displayed optical activity in solution. Both melting and glass‐transition temperatures of the copolyesters were observed to steadily decrease with the content in DMBD. PEDMBTs were found to be crystalline for contents in DMBD up to 30 mol %. Both powder and fiber X‐ray diffraction revealed that the same crystalline structure is shared by PET and the crystalline copolyesters. The homopolyester PDMBT resulted in becoming a polymer with a crystallinity comparable to PET but with a significantly different crystalline structure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3250–3262, 2001 相似文献
14.
Hiroshi Katagiri Masao Morimoto Kenichi Sakai 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):o357-o360
The structures of diastereomeric pairs consisting of (S)‐ and (R)‐2‐methylpiperazine with (2S,3S)‐tartaric acid are both 1:1 salts, namely (S)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C5H14N22+·C4H4O62−·2H2O, (I), and (R)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C5H14N22+·C4H4O62−·2H2O, (II), which reveal the formation of well defined ammonium carboxylate salts linked via strong intermolecular hydrogen bonds. Unlike the situation in the more soluble salt (II), the alternating columns of tartrate and ammonium ions of the less soluble salt (I) are packed neatly in a grid around the a axis, which incorporates water molecules at regular intervals. The increased efficiency of packing for (I) is evident in its lower `packing coefficient', and the hydrogen‐bond contribution is stronger in the more soluble salt (II). 相似文献
15.
Hiroshi Katagiri Masao Morimoto Kenichi Sakai 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(1):o20-o24
The crystal structures of a pair of diastereomeric 1:2 salts of (R)‐ and (S)‐2‐methylpiperazine with (2S,3S)‐tartaric acid, namely (R)‐2‐methylpiperazinediium bis[hydrogen (2S,3S)‐tartrate] monohydrate, (I), and (S)‐2‐methylpiperazinediium bis[hydrogen (2S,3S)‐tartrate] monohydrate, (II), both C5H14N22+·2C4H5O6−·H2O, each reveal the formation of well‐defined head‐to‐tail‐connected hydrogen tartrate chains; these chains are linked into a two‐dimensional sheet via intermolecular hydrogen bonds involving hydroxy groups and water molecules, resulting in a layer structure. The (R)‐2‐methylpiperazinediium ions lie between the hydrogen tartrate layers in the most stable equatorial conformation in (I), whereas in (II), these ions are in an unstable axial position inside the more interconnected layers and form a larger number of intermolecular hydrogen bonds than are observed in (I). 相似文献
16.
Silvia Russi Leopoldo Suescun Alvaro Mombrú Helena Pardo Raúl A. Mariezcurrena Gabriel Cavalli Gustavo Seoane 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):820-821
The title compound, [Fe(C8H11ClO2)(CO)3], has been synthesized, isolated and characterized by single‐crystal X‐ray diffraction. The molecule crystallizes in the orthorhombic space group P212121. The metal–ligand arrangement is typical of (1,3‐diene)tricarbonyliron complexes. 相似文献
17.
Smaranda Cota Dipl.‐Chem. Matthias Beyer Dipl.‐Chem. Rüdiger Bertermann Dr. Christian Burschka Dr. Kathrin Götz Dr. Martin Kaupp Prof. Dr. Reinhold Tacke Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(22):6582-6589
The neutral hexacoordinate silicon(IV) complex 6 (SiO2N4 skeleton) and the neutral pentacoordinate silicon(IV) complexes 7 – 11 (SiO2N2C skeletons) were synthesized from Si(NCO)4 and RSi(NCO)3 (R=Me, Ph), respectively. The compounds were structurally characterized by solid‐state NMR spectroscopy ( 6 – 11 ), solution NMR spectroscopy ( 6 and 10 ), and single‐crystal X‐ray diffraction ( 8 and 11 were studied as the solvates 8? CH3CN and 11? C5H12 ? 0.5 CH3CN, respectively). The silicon(IV) complexes 6 (octahedral Si‐coordination polyhedron) and 7 – 11 (trigonal‐bipyramidal Si‐coordination polyhedra) each contain two bidentate ligands derived from an α‐amino acid: (S)‐alanine, (S)‐phenylalanine, or (S)‐tert‐leucine. The deprotonated amino acids act as monoanionic ( 6 ) or as mono‐ and dianionic ligands ( 7 – 11 ). The experimental investigations were complemented by computational studies of the stereoisomers of 6 and 7 . 相似文献
18.
Two new chiral alcohols, 2(S)‐[2(R)‐methylhexyloxy]propanol ( 5 ) and 2(S)‐[2(S)‐methylhexyloxy]propanol ( 6 ), were prepared from the corresponding propionic acid ethyl ester 1 and 2 in the presence of sodium borohydride. They were used as the chiral moiety for the synthesis of two diastereomeric liquid crystals 7 and 8 . Both of them exhibit the phase sequence I‐SmA‐SmC*‐SmX‐Cr. The mesogenic properties of the (S,S)‐diastereomer 8 are more unique in comparison with those of the (S,R)‐diastereomer 7. It possesses not only lower SmA and SmC* phase transition temperature, 103 °C vs. 112 °C for SmA phase and 31 °C vs. 65 °C for SmC* phase, but wider SmA and SmC* phase range, 40 °C vs. 31 °C for SmA phase and 72 °C vs. 47 °C for SmC* phase. The diastereomer 8 also has a larger Ps value than that of 7, 24 vs. 15 nC cm?2 measured at Tc ‐ T = 10 °C. The difference in these mesogenic properties is discussed by comparing their conformation difference at the molecular part of benzoate. 相似文献
19.
Jarno Kansikas Kaija Sipil 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1383-1385
In the synthesis of 1‐phenyl‐2‐phenylthio‐2‐(tetrahydropyran‐2‐ylthio)ethanol, C19H22O2S2, four diastereoisomers are formed. Two non‐centrosymmetric enantiomeric forms which crystallize in space groups P212121 and Pna21 are presented. The former has an intramolecular hydrogen bond between the hydroxyl group and the O atom of the tetrahydropyran ring. In the latter isomer, the hydroxyl group forms an intermolecular hydrogen bond to the O atom of the tetrahydropyranyl group of a neighbouring molecule, joining the molecules into chains in the c‐axis direction; the O?O distances are 2.962 (4) and 2.764 (3) Å, respectively. The tetrahydropyran rings are in chair conformations in both isomers and the S side chain has an equatorial orientation in the former, but an axial orientation in the latter molecule. 相似文献
20.
Wen Xu Guoqun Liu Gang Xue Wentao Yu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):m436-m438
The crystal structure of the title compound, (C16H36N)[Ni(C3S5)2], is isomorphous with that of the corresponding Pt complex but different from the structures reported for compounds of the same chemical composition, and so provides a new crystalline phase of this complex. The nickel complex anion has good planarity and lies on a crystallographic inversion centre. There is disorder in the two terminal C atoms of two of the butyl chains of the tetra‐n‐butylammonium cation, the N atom of which is located on a twofold axis. 相似文献