o‐Amine‐Assisted Cannizzaro Reaction of Glyoxal with New 2,6‐Diaminoanilines

Abstract The preparation of several new o ‐amine‐substituted anilines was achieved according to a new bifunctional molecular design, and their reactions with glyoxal were conducted. Cannizzaro reactions of glyoxal proceeded using specifically designed anilines, such as 2,6‐dipyrrolidinyl‐, 2,6‐dipiperidinyl‐, 2,6‐dimorpholinyl‐, and 2‐pyrrolidinyl‐aniline, which are new and can easily be synthesized by substitution of halogen‐substituted nitrobenzene with amines and subsequent reduction with hydrogen, to form α‐hydroxy acetamide and α‐amino acetamide derivatives, as a result of the Cannizzaro reaction. In comparison with the reaction of glyoxal with p ‐pyrrolidinylaniline to form a common diimine product, the reaction with o ‐pyrrolidinylaniline leads only to α‐hydroxy amides, strongly suggesting that the abnormal Cannizzaro reactions are attributed to the existence of basic nitrogen atoms at the o ‐positions, which suppress diimine formation and assist the generation of acetamides.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)