A process of preparing an azetidinone compound of the general formula:
wherein R1 is 1-hydroxyethyl, a protected 1-hydroxyethyl wherein the hydroxy group is protected by a conventional protecting group for a hydroxy group or vinyl, and R2 is hydrogen or mono- or diarylmethyl, comprises oxidatively decarboxylating a carboxylic acid compound of the formula:
wherein R1 and R2 are as defined above, with lead tetraacetate in an inert solvent in the presence or absence of a base or a salt.
A compound of the formula (b) where R' is CH3-COH-and the -COOH group can also be protected carboxyl or acetoxy and R2 is not H can be prepared from a compound:
by oximercuration with mercuric acetate and reductive demercuration with a reducing agent in an inert solvent.
Methods of preparing the starting materials are shown.
The final compounds (b) are useful for preparing β-lactams as described in EP-0 070 204A.
一种制备通式为氮杂
环丁酮化合物的工艺:
其中 R1 是 1-羟乙基、被保护的 1-羟乙基(其中羟基被羟基的常规保护基团或
乙烯基保护)和 R2 是氢或单或二芳基甲基,包括氧化脱羧式的
羧酸化合物:
其中 R1 和 R2 如上定义,在有或没有碱或盐的情况下,在惰性溶剂中用四
乙酸铅进行氧化脱羧。
式(b)的化合物,其中 R' 是
CH3-COH,-COOH 基团也可以是受保护的羧基或乙酰氧基,R2 不是 H,可以由以下化合物制备:
在惰性溶剂中用
乙酸巯基进行氧化缩合,再用还原剂进行还原脱缩合。
制备起始材料的方法如图所示。
如 EP-0 070 204A 所述,最终化合物 (b) 可用于制备 β-内酰胺。