AROMATIZATION OF 1 , CDIHYDROPYRIDINES WITH OXYGEN OR AIR USING MANGANESE AND COBALT SALTS OF p-AMINOBENZOIC ACID SUPPORTED ON SILICA GEL AS OXIDIZING CATALYSTS

Abstract
Hantzsch 1,4-dihydropyridines are oxidized to the corresponding pyridine
derivatives using oxygen or air and a mixture of the manganese and cobalt salts of parninobenzoic
acid supported on silica gel as the catalysts. Reactions are clean and the
catalysts can be recovered easily and reused repeatedly.