Synthesis of 7-hydroxyspiropyran

Abstract

The 7-acetoxyspiropyrans (4a and 4b) have been prepared by the reaction of Fischer's bases (3) with 2,4-diacetoxybenzaldehyde in refluxing ethanol in moderate yields. The acetyl group of 7-acetoxyspiropyran 4a was easily removed to give a 7-hydroxyspiropyran 6 in high yield under the basic condition.