Abstract
Reaction of ethyl 4-bromoacetoacetate (1) with phenol in the presence of aluminum chloride gave ethyl 4-bromo-3-hydroxy-3-(2-hydroxyphenyl) butyrate (3a), which can be regarded as an intermediate of the Pechmann reaction. Similar reaction of ethyl 4-chloroacetoacetate (7) with phenol in the presence of aluminum chloride gave the 4-chloroderivative 8a. Compound 3a was treated with either hydrogen chloride in ethanol or triethylamine followed by treatment with p-toluenesulfonic acid to give 4-bromomethylcoumarin (4a) or ethyl 3-benzo [b] furanacetate (6a), respectively. Similarly, reactions of phenol derivatives 2 with 1 gave the corresponding 3-hydroxy-butyrates 3, which were transformed to the coumarins 4 and the 3-benzo [b] furanacetates 6.
