PREPARATION OF IMIDAZOLONES FROM N-CYANO-N'-METHYLCARBOXYGUANIDINES -AN UNUSUAL C-N BOND FORMATION IN THE HYDROGENOLYSIS OF A BENZYL ESTERIN AN ATTEMPTED SYNTHESIS OF AN INHIBITOR OF CARBOXYPEPTIDASE-A

Hydrogenolysis of the benzyl ester 5 gave the imidazolone 6 rather tha n the desired acid 1, and the related benzyl ester 11 also hydrogenoly sed to the imidazolone 12. Examination of the hydrolysis of simpler gu anidine derivatives with trifluoroacetic acid suggested a unified mech anism for these processes which, in the case of the imidazolones, invo lves the intramolecular formation of a 7-membered ring intermediate. T he hydrolytic reactions provide useful, high yield methods for transfo rming the N-cyanoimine group into other functional groups.