THE INFRARED SPECTRA OF SOME CYCLIC MALONATES

Abstract

The infrared spectra of isopropylidene malonate and some of its derivatives have been examined and compared with those of open-chain malonate esters and of 5,5-dimethylcyclohexane-1,3-dione. Two bands in the carbonyl stretching region are attributed to vibrational coupling of the carbonyl groups in the cyclic esters. There is no evidence that isopropylidene malonate exists in the enolic form either in the solid state or in chloroform solution. This cyclic ester structure for "Meldrum's acid" is thus confirmed.