Some Remarks Concerning the Publication ‘A Novel Synthesis of 3-Substituted Pyruvic Acids; A New Route to’, β-Diamino Acids' by M. M. Kidwai, N. H. Khan and M. Ali

Abstract

Recently N. H. Khan and cowcrkers published an unprecedented C-C-bond formation by heating 4-arylidene-2-phenyl-2-oxazolin-5-ones with anhydrous formic acid

(‘fornic acid process’)¹. We repeated this reaction with 4-benzylidene-2-phenyl-2-oxazolin-5-one (1) and formic acid (98–100%, Merck, p.A.) several times, however, we were unable to obtain any α-oxocarboxylic acid 2 as has been claimed by the authors. After 30 min of reflux mainly starting material and some hydrolysis product 3 could be isolated, whereas prolonged heating (3-5h) qave 2-benzcylaminocinnamic acid (3), m.p. 232°C in high yield. We were unable to defect any CO evolution.