Amidine systems containing an indole structure

1. A number of substituted amidines of 3-indoleacetic acid have been synthesized, in which the carboxy-containing residues of D, L-α-amino acids have been used as N-substituents, plus their ethyl esters. 2. The cyclization of some of the compounds prepared to 2-(3′-mdolylmethyl)-4-isobutyl-5-imidazolone and 2,4-di(3′-indolylmethyl)-5-imidazolone has been effected.