Preparation of 4,5-dihydro-1,3-selenazoles by reaction of aromatic primary selenoamides with acetylenedicarboxylate

Reactions of primary selenoamides with dimethyl acetylenedicarboxylate afforded 2-aryl-5-methoxycarbonylmethylene-4,5-dihydro-1,3-selenazol-4-ones in moderate to high yields. Reactions of the primary selenoamides with acetylenedicarboxylic acid gave 2-aryl-5-carboxymethylene-4-ethoxy-4,5-dihydro-1,3selenazol-4-ols in moderate yields.