2-chlorosulfinyl-azetidin-4-ones of the formula
wherein R is the residue of a carboxylic acid and R is a carboxylic acid protecting group, are prepared by reacting a penicillin sulfoxide ester of the formula
wherein R and R1 are as defined above, with an N-chlorohalogenating agent, e.g. N-chlorophthalimide, in ar, inert organic solvent, e.g. toluene, under essentially anhydrous conditions in the presence of a cross-linked polyvinylpyridine polymer, e.g. poly-(4-vinylpyridine), said polymer containing between about 1 percent and about 10 percent cross-linking with e.g. divinylbenzene.
The 2-chlorosulfinylazetidin-4-ones are used as intermediates for the preparation of 3-exomethylenecepham-4-carboxylic acid ester sulfoxides.
式中的 2-
氯亚磺酰基氮杂
环丁烷-4-酮,其中 R 是
羧酸残基,R 是
羧酸保护基团。
式中 R 为
羧酸残基、R 为
羧酸保护基团的 2-
氯亚磺酰基-氮杂
环丁烷-4-酮,是由式中的
青霉素亚砜酯与 N-
氯卤化剂(如 N-
氯酞酰亚胺)反应制备的。
其中 R 和 R1 如上定义,在 ar 惰性有机溶剂(如
甲苯)中,在基本无
水条件下,在交联聚
乙烯吡啶聚合物(如聚-(
4-乙烯基吡啶))存在下,与 N-
氯卤化剂(如 N-
氯邻苯二甲
酰亚胺)反应,所述聚合物含有约 1%至约 10%的
交联剂(如
二乙烯基苯)。
2-chlorosulfinylazetidin-4-ones 可用作制备 3-exomethylenecepham-4-carboxylic acid ester sulfoxides 的中间体。