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Synthesis of optically active penems

✍ Scribed by V.M. Girijavallabhan; A.K. Ganguly; S.W. McCombie; P. Pinto; R. Rizvi

Publisher: Elsevier Science
Year: 1981
Tongue: French
Weight: 227 KB
Volume: 22
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(01)81938-9

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✦ Synopsis

A general synthesis for optically active penems is described. Penems undergo a novel thermal isomerisation reaction. Won-classical B-lactams, exemplified by thienamycin', olivanic acidl and the Woodward's novel synthetic "penem" have all been described as potent antimicrobial agents. Recently, Several Papers have appeared on the syntheses of Cs-substituted penems'+-a, A Merck group9 has also announced a chiral synthesis forpenems, which is now established to be inoperativelO-ll. In this communication, we wish to report a general chiral synthesis for novel Cs-carbon substituted penems. The relatively inexpensive and readily available 6-amino penicillanic acid (1) (6-APA) was diazotized and brominated using a modified12 Clayton procedure13. The crystalline methyl ester (2) was obtained (-70%) by esterification of the dibromo penicillanic acid with methyl iodide in the presence of K2C03 in DMF.

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