AN EFFCIENT SYNTHESIS OF 1,4-DIHYDRO-6-TRIFLUOROMETHYLPYRIDINES: A FACILE AND USEFUL METHOD FOR DEHYDRATION OF alpha-TRIFLUOROMETHYL ALCOHOLS BY USE OF PHOSPHOROUS OXYCHLORIDE/PYRIDINE ADSORBED ON SILICA GEL

摘要

The treatment of alpha-alkoxycarbonyI-alpha,beta-unsaturated trifluoromethyl ketones (1) with beta-aminocrotonates (2) affords 2-hydroxy-6-methyl-2-trifluoromethyl-1,2,3,4-tetrahydropyridines (3), which undergo facile dehydration by use of phosphorus oxychloride / pyridine adsorbed on silica gel, giving good to high yields of 1,4-dihydro-2-methyl-6-trifluoromethylpyridines (4).