Novel condensation products of 3-Hydroxy-2,2-dimethylpropionaldehyde with malonic acid

Abstract

Reaction of 3-hydroxy-2,2-dimethylpropionaldehyde and malonic acid in acetic anhydride-acetic acid yields 4,4-dimethylpent-2-en-5-olide, corresponding to the normal product of condensation of one molecule of aldehyde and one molecule of malonic acid, along with two novel related δ-lactones derived from two molecules of aldehyde and one molecule of malonic acid: one is a saturated lactone having a hydroxy-gem- dimethyltetrahydropyran ring fused across the 2,3-bond of the above normal product, and the other is the corresponding unsaturated fused dihydropyranolactone.