The reduction of 4-thiazones and N-acetyl-4-thiazone-imines with sodium borohydride gave thiazolidin-4-ones and 4-acetylaminothiazolidines respectively. Attempts to isomerize 5- alkylidenethiazolidin-4-ones, prepared by the reduction of 5-acyl-4-thiazones, followed by dehydration, to 5-alkyl-4-thiazones were unsuccessful. The ethylation and acetylation of 2, 3, 5-triphenyl-4-thiazone gave the corresponding 4-ethoxy-and 4-acetoxy-thiazolium salts.
