Reaction of 5-arylmethylene-2-thioxo-4-thiazolidinones with some phosphonium ylides. Synthesis of thiazolidino[4,5-x]-fused compounds

Article abstract of DOI:10.1016/0040-4020(95)00705-D

The reactions of the entitled compounds (4a) and (4b) with some phosphonium ylides (5a-d) have been studied in considerable detail. By applying the Wittig reagents (5a,b) on the thiazolidinones (4a,b) in refluxing ethyl acetate and in the presence of triethylamine, conjugated dihydro-furo[2,3-d]thiazol-2(3H)-ones (7a-d) were obtained while carrying out the reaction in refluxing toluene and also in the presence of triethylamine led to the formation of the pyrone derivatives (8). Reaction of 4a,b with oxoylide (5c), afforded the pyranderivatives (10). On the contrary, the reaction of 4a,b with 5d underwent 1,2-addition reaction to yield the new ylides (12a,b) as a sole reaction product. Except the last reaction of 4a,b with 5d, other reactions afforded, in each instance, the olefinated products (9a-d) and (11a,b) in 11-18% yield.