Synthesis of Benzopyranoisoxazol-4-ones from 2-Substituted Chromone-3-carboxylic Esters. A Reinvestigation of the Reaction of 3-Acetyl-4-hydroxycoumarins with Hydroxylamine. Synthesis of 4-(2-Hydroxybenzoyl)isoxazol-5-ones

Article abstract of DOI:10.1021/jo00197a018

A convenient method for the synthesis of ethyl 2-substituted chromone-3-carboxylates by the condensation of o-acetoxyaroyl chlorides with β-keto esters is described.These chromones are converted into the corresponding 4H-<1>benzopyrano<3,4-d>isoxazol-4-on