In the eighth paper of this series' the reactions between ketene diethylacetal and a variety of a, p-unsaturated carbonyl compounds' were reported. One of these unsaturated carbonyl compounds was+ benzoquinone which was found to react with ketene acetal readily in rduxing benzene to give a white crystalline product, mp 94-95', that was converted to hydroquinoneacetic (homogentisic) acid by hydrolysia in acid solution. This reaction ...