The influence of remote substituents on amide bond formation. The reaction of oxazolinones with benzylamine

Abstract

The second-order rate constants for the reaction of nine substituted (Z)-4-benzylidene-2-phenyloxazolin-5-ones with benzylamine in acetonitrile have been obtained. There is an electronic effect in the predicted direction for substitution in either ring. There is a difference in steric effects which appears to be ring specific. ortho-Substituents in the benzylidene ring lead to rate enhancement while ortho-substituents in the phenyl ring retard the rate. The reaction of the oxazolinones with α-methylbenzylamine indicates a large steric effect upon increasing steric demand in the nucleophile.