Abstract 4-Alkoxy-1, 3-oxazol-5 (2H)-ones of type 4 and 7 were synthesized by two different methods: oxidation of the 4-(phenylthio)-1, 3-oxazol-5 (2H)-one 2a with m-chloroperbenzoic acid in the presence of an alcohol gave the corresponding 4-alkoxy derivatives 4, presumably via nucleophilic substitution of an intermediate sulfoxide (Scheme 2). The second approach is the BF 3-catalyzed condensation of imino-acetates of type 6 and ...
![3-methoxy-1-oxa-4-azaspiro[4.5]dec-3-en-2-one结构式](https://image.chemsrc.com/caspic/340/85976-46-1.png)
