Chlorination of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′-difluoromethoxyphenyl)-1,4-dihydropyridine (phoridone)

Chlorination of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′-difluoromethoxyphenyl)-1,4-dihydropyridine gives 2,3,4,5-tetrahydropyridines with different degrees of chlorination dependent upon the quantitative ratio of reagents. The reaction proceeds without oxidation of the dihydropyridine ring.