Synthesis and Properties of Ethyl Esters of 4-Dialkylamino-2-methylthiothieno[2,3-d]pyrimidine-6-carboxylic Acids

The reaction of 4-dialkylamino-6-chloro-2-methylthiopyrimidine-5-carbaldehydes with ethyl mercaptoacetate in the presence of triethylamine gives the corresponding ethyl esters of thieno[2,3-d]pyrimidine-6-carboxylic acids. These esters were subjected to alkaline hydrolysis, hydrazinolysis, and lithium aluminum hydride reduction to give the corresponding acids, hydrazides, and (thieno[2,3-d]pyrimidin-6-yl)methanols.