Compounds of the formula Ia and their tautomers Ib ##STR1## in which formulae R represents a carboxyl esterifying group are described, as well as processes for their manufacture. Ia and Ib are valuable starting materials for the preparation of various derivatives substituted at position 3 that possess antibacterial properties.
化合物Ia的公式及其互变异构体Ib如下所示,其中公式中的R代表一个
羧酸酯化基团,同时还描述了它们的制备过程。Ia和Ib是制备具有抗菌性质的在位置3处被取代的各种衍
生物的宝贵起始物质。