The Synthesis of Methoxy- and Hydroxy-Substituted Cinnamaldehydes and Their Corresponding Epoxides. II. The Epoxides

Abstract

The formation and stability of the epoxides of 4-hydroxy-3,5-dimethoxycinnamaldehyde, 3,4,5- trimethoxycinnamaldehyde, 4-hydroxy-3-methoxycinnamaldehyde and 3,4-dimethoxycinnamaldehyde and the diacetates of these aldehydes have been studied under a variety of epoxidation conditions. m-Chloroperbenzoic acid in chloroform was the most successful epoxidizing agent. The epoxidation of 3,4,5-trimethoxycinnamylidene and 4-methoxycinnamylidene diacetates was followed, in each case, by ring cleavage of the newly formed epoxide diacetate. The epoxidation of 4-acetoxy-3,5- dimethoxycinnamylidene and 4-acetoxy-3-methoxycinnamylidene diacetates proceeded normally with the formation of the corresponding epoxides. Hydrolysis of these epoxides with magnesium hydroxide suspension gave a mixture of cleavage products, e.g. the α,β-dihydroxy aldehydes (26) and (27) from 4-acetoxy-3-methoxycinnamylidene diacetate epoxide.