NOVEL SYNTHESES OF THE MAJOR FLAVOR COMPONENTS OF BREAD AND COOKED RICE

A new synthetic pathway toward the Maillard flavor compounds 6-acyl-1, 2,3,4-tetrahydropyridines and 2-acetyl-1-pyrroline is presented. The r eaction sequence involves deprotonation of a vicinal diimine and subse quent alkylation with an N,N-diprotected omega-bromoalkylamine, follow ed by deprotection and intramolecular transimination of the functional ized intermediate. Acidic workup affords the above-mentioned heterocyc les, which are principal flavor constituents of bread and cooked rice, respectively. In addition, the synthesis of the more stable diethyl a cetal of 2-acetyl-1-pyrroline is described.