Synthesis of 2-sulfanyl-6-methyl-1,4-dihydropyrimidines as a new class of antifilarial agents.

Abstract A series of 2-sulfanyl-6-methyl-1,4-dihydropyrimidines ( 8 – 21 ) were synthesized in good yields by alkylation of 5-methyl-6-phenyl-2-thioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid ethyl esters ( 2 – 7 ) with different alkyl or aralkyl halides in the presence of a combination of anhydrous K 2 CO 3 and catalytic amount of tetrabutyl ammonium bromide. The title compounds were evaluated for their antifilarial activity against adult parasites of human lymphatic filarial parasite Brugia malayi (sub-periodic strain) in vitro and in vivo at various concentrations. One of the compounds ( 18 ) showed promising antifilarial activity.