REACTION OF α-CYANOACRYLATES WITH FUNCTIONALLY SUBSTITUTED THIOLS, ETHANEDITHIOL, AND HYDROGEN SULFIDE

Article abstract of DOI:10.1007/BF00959721

Functionally substituted thiols, i.e., thioglycolic acid and cysteamine and cysteine hydrochlorides, facilely undergo addition at the double bond of α-cycnoacrylates, forming the corresponding adducts in quantitative yields: R'SCH2CH(CN)COOR .Under similar conditions, the reaction with ethanedithiol gives the diadduct 2; the monoadduct HSCH2CH2SCH2CH(CN)COOR is formed in a significantly lower yield.Hydrogen sulfide does not undergo addition to α-cyanoacrylate in the absence of a catalyst; S2 is formed quantitatively in the presence of Et3N.In the presence of triethylamine, this sulfide undergoes intramolecular cyclization (the Ziegler-Thorpe reaction) with formation of 4-amino-5-cyano-3,5-bis(ethoxycarbonyl)thiacyclohex-3-ene.