Syntheses of chiral intermediates of 1-β-methylcarbapenems: (3S,4R)-3-[1(R)-tert-butyldimethylsilyloxyethyl]-4-chloroazetidin-2-one and (3S,4S)-3-[1(R)-tert-butyldimethylsilyloxyethyl]-4-[1(R)-tert-butylthiocarbonylethyl]azetidin-2-one
摘要:
4-氯吡嗪酮10是1-β-甲基卡巴比林(1b)的非常活性手性中间体,可以从相应的硫醚5中轻松制备并分离为固体结晶化合物。另一个携带1-β-甲基基团的手性中间体(16d)是通过对吡嗪酮4或10与金属烯醇酸盐14(R = S—Bu',M = ZrCp2Cl,[Formula: see text]和SnBr)的立体选择性醛缩反应制备的。β/α比例分别为9:1,3:1,2:1。
Syntheses of chiral intermediates of 1-β-methylcarbapenems: (3S,4R)-3-[1(R)-tert-butyldimethylsilyloxyethyl]-4-chloroazetidin-2-one and (3S,4S)-3-[1(R)-tert-butyldimethylsilyloxyethyl]-4-[1(R)-tert-butylthiocarbonylethyl]azetidin-2-one
摘要:
4-氯吡嗪酮10是1-β-甲基卡巴比林(1b)的非常活性手性中间体,可以从相应的硫醚5中轻松制备并分离为固体结晶化合物。另一个携带1-β-甲基基团的手性中间体(16d)是通过对吡嗪酮4或10与金属烯醇酸盐14(R = S—Bu',M = ZrCp2Cl,[Formula: see text]和SnBr)的立体选择性醛缩反应制备的。β/α比例分别为9:1,3:1,2:1。
2-Thioalkyl penems: an efficient synthesis of sulopenem, a (5R,6S)-6-(1(R)-hydroxyethyl)-2-[(cis-1-oxo-3-thiolanyl)thio]-2-penem antibacterial
作者:Robert A. Volkmann、Paul R. Kelbaugh、Deane M. Nason、V. John Jasys
DOI:10.1021/jo00042a010
日期:1992.7
A practical synthesis of potent penem antibacterials, CP-70,429 (1) (sulopenem) and CP-81,054 (2), is described. (L)-Aspartic acid was utilized to generate both the (3S)- and (3R)-thiolanylthio side chains of (5R,6S)-6-(1-(R)-hydroxyethyl)-2-[(cis-1-oxo-3-thiolanyl)thio]-2-penem-3-carboxylic acids 1 and 2. This synthetic pathway provided in high yield enantiopure thioacetate intermediates 15 and 19. To accommodate the fragile side chain sulfoxide moiety of the targeted beta-lactams, standard penem synthetic methodology was modified to facilitate the conversion of 15 and 19 to 1 and 2. The reactive chloroazetidinone 4b was utilized to generate key azetidinone trithiocarbonate intermediate 22 which contains the requisite penem side chain. A chemoselective oxalofluoride-based azetidinone N-acylation procedure, which avoids sulfoxide O-acylation, was required for the conversion of 22 to the penem framework.
Desulphurative approaches to penem antibiotics. II. 4-acyldithioazetidin-2-ones from penicillin derived sulphenimides, thiolsulphonates and disulphides.