Carbon‐13 n.m.r. spectra of branched carboxylic acids and their derivatives

Abstract

Abstract 13 C n.m.r. spectra have been measured for 39 compounds with branched structures including carboxylic acids, their methyl and ethyl esters, nitriles and chlorinated esters. The results obtained indicate that the 13 C n.m.r. technique is applicable to structure assignment of acids and their derivatives containing various numbers of substituents on the chain. The dependence of the carboxylic carbon chemical shift on the number and structure of α‐positioned substituents has been determined. Calculation of the chemical shifts for branched carboxylic acids, esters and nitriles from the corresponding increments using the additivity scheme is shown to be possible in principle.