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Srinivas Tekkam Joseph L. Johnson Subash C. Jonnalagadda Venkatram R. Mereddy 《Journal of heterocyclic chemistry》2013,50(4):955-958
A concise protocol for the synthesis of α‐methylene‐β‐hydroxy‐γ‐carboxy‐γ‐lactams has been described via alkylation of amino acid derived iminoesters with α‐bromomethylmethacrylate, followed by allylic hydroxylation. All the synthesized compounds have been evaluated for their cytotoxicity on multiple myeloma cancer cell lines. 相似文献
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Wenhui Zhang Allen G. Oliver Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(11):o557-o560
3‐Deoxy‐3‐fluoro‐d ‐glucopyranose crystallizes from acetone to give a unit cell containing two crystallographically independent molecules. One of these molecules (at site A) is structurally homogeneous and corresponds to 3‐deoxy‐3‐fluoro‐β‐d ‐glucopyranose, C6H11FO5, (I). The second molecule (at site B) is structurally heterogeneous and corresponds to a mixture of (I) and 3‐deoxy‐3‐fluoro‐α‐d ‐glucopyranose, (II); treatment of the diffraction data using partial‐occupancy oxygen at the anomeric center gave a high‐quality packing model with an occupancy ratio of 0.84:0.16 for (II):(I) at site B. The mixture of α‐ and β‐anomers at site B appears to be accommodated in the lattice because hydrogen‐bonding partners are present to hydrogen bond to the anomeric OH group in either an axial or equatorial orientation. Cremer–Pople analysis of (I) and (II) shows the pyranosyl ring of (II) to be slightly more distorted than that of (I) [θ(I) = 3.85 (15)° and θ(II) = 6.35 (16)°], but the general direction of distortion is similar in both structures [ϕ(I) = 67 (2)° (BC1,C4) and ϕ(II) = 26.0 (15)° (C3TBC1); B = boat conformation and TB = twist‐boat conformation]. The exocyclic hydroxymethyl (–CH2OH) conformation is gg (gauche–gauche) (H5 anti to O6) in both (I) and (II). Structural comparisons of (I) and (II) to related unsubstituted, deoxy and fluorine‐substituted monosaccharides show that the gluco ring can assume a wide range of distorted chair structures in the crystalline state depending on ring substitution patterns. 相似文献
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A concise synthesis of α‐benzylidene‐γ‐methyl‐γ‐butyrolactones 5a – g from substituted benzaldehydes is described. Compounds 1a – g on reaction with phosphorane 2 , provide the pentenoates 3a – g , which can be hydrolyzed to the acids 4a – g . The latter are cyclized to the corresponding butyrolactones 5a – g in excellent yields. The pentenoates 3a – g , on acid catalyzed cyclization, also provide 5a – g in very high yields. 相似文献
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Slobodanka Stankovi Duan Lazar Ljubica Medi‐Mija
evi Katarina Penov‐Gai Marija Saka
Silvana Andri Bruvo Milenko 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o172-o173
The title molecule, C26H30O3, shows a novel chemical rearrangement of the substituents at position 17, i.e. an α‐orientation of the hydroxy group and a β‐orientation of the bulky benzyl moiety. The packing arrangement consists of coils formed by O2?O3 hydrogen bonds along the c axis. The compound shows complete loss of oestrogenic activity, and neither does it exhibit an antagonistic effect. 相似文献
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Zdenko Hamerak Dajana Gao Spomenka Kova
Antonija Hergold‐Brundi Ivan Vickovi Vitomir unji 《Helvetica chimica acta》2003,86(6):2247-2257
Aldol reaction of 7‐chloro‐1,3‐dihydro‐1‐methyl‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one ( 1 ) with 4‐substituted α‐methylcinnamaldehydes 2 – 5 afforded a mixture of threo‐ and erythro‐3‐(3‐aryl‐1‐hydroxy‐2‐methylprop‐2‐enyl)‐7‐chloro‐1,3‐dihydro‐1‐methyl‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐ones 6 – 13 . The chromatographically separated threo diastereoisomers 6, 8, 10 , and 12 and erythro diastereoisomers 7, 9, 11 , and 13 were submitted to ‘directed' homogeneous hydrogenation catalyzed by [RhI(cod)(diphos‐4)]ClO4 (cod=cycloocta‐1,5‐diene, diphos‐4=butane‐1,4‐diylbis[diphenylphosphine]. From the erythro‐racemates 9, 11 , and 13 , the erythro,erythro/erythro,threo‐diastereoisomer mixtures 16 / 17, 20 / 21 , and 24 / 25 were obtained in ratios of 20 : 80 to 28 : 72 (HPLC), which were separated by chromatography. From the threo racemates 8, 10 , and 12 , the threo,threo/threo,erythro‐diastereoisomer mixtures were obtained in a ratio of ca. 25 : 75 (1H‐NMR). The relative configurations were assigned by means of 1H‐NMR data and X‐ray crystal‐structure determination of 21 . Hydrolysis of 21 afforded the diastereoisomerically pure N‐(benzyloxy)carbonyl derivative 27 of α‐amino‐β‐hydroxy‐γ‐methylpentanoic acid 26 , representative of the novel group of polysubstituted α‐amino‐β‐hydroxycarboxylic acids. 相似文献
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Fathy M. Abdelrazek Nehal A. Sobhy Peter Metz Akram A. Bazbouz 《Journal of heterocyclic chemistry》2012,49(2):381-387
3‐Oxo‐N‐[4‐(3‐oxo‐3‐phenylpropionylamino)‐phenyl]‐3‐phenylpropionamide 1 and its derivative 2‐benzoyl‐N‐[4‐(2‐benzoyl‐3‐(dimethylamino‐acryloylamino)‐phenyl]‐3‐dimethylaminoacrylamide 12 are used for the synthesis of the hitherto not known bis‐heterocyclic amine and bis‐heterocyclic carboxamide derivatives. Plausible mechanisms are discussed for the formation of the new compounds. J. Heterocyclic Chem., (2012). 相似文献