An improved procedure for the preparation of 3-carbomethoxy-4-oxotetrahydrothiopyran, 2- and 4-carbomethoxy-3-oxotetrahydrothiophene

Article abstract of DOI:10.1139/v82-065

An improved procedure for the preparation of the title compounds 1-3 has been developed.Direct condensation of methyl 3-mercaptopropionate with methyl acrylate using sodium hydride as a base gave compound 1 in good yield.The reaction of methyl thioglycolate and methyl acrylate at 0 degC gave compound 2 as the major product whereas at lower temperature (-40 degC) isomer 3 was found as the major product.The condensation reactions of methyl thioglycolate with methyl metacrylate and crotonate were also carried out.