Synthesis and substitution reactions of 4(6)-chlorodihydropyrimidines

Chlorination of the corresponding ketones with phenylphosphonic dichloride (PhPOCl₂) provided ethyl 6(4)-chloro-2-methyl-4(6)-phenyl-1,4(6)- dihydropyrimidine-5-carboxylate in good yield. The cross-coupling reactions of organoboronic acids or triethylborane with 1-tert-butyl 5-ethyl 4-chloro-2- methyl-6-phenyl-1,6-dihydropyrimidine-1,5-dicarboxylate synthesized by regiospecific alkoxycarbonylation of the chlorinated dihydropyrimidine afforded 1,4(3,4)-dihydropyrimidines having a variety of functional groups at position-6(4) in good to excellent yields.