Studies on Acetylenic Compounds. XLVI. The Reactions of Acetylenic Compounds with Thiourea or Ammonium Dithiocarbamate

Abstract

Treatment of ethyl propiolate (I) with thiourea or ammonium dithiocarbamate under neutral conditions gave diethyl cis-cis-β, β'-thioacrylate (II), stereospecifically. Analogously II was obtained from ethyl cis-β-chloroacrylate and the same reagents. II was easily converted to trans-trans-II (XII) by heating or irradiation. On the other hand, the reactions of β-substituted acetylenic acid esters (XVII a-f) with thiourea afforded the corresponding 1, 3-thiazine derivatives (XVIII a-f), unexpectedly. The reactions of propiolonitrile (XX), tetrolonitrile (XXIII) and phenylpropiolonitrile (XXV) with thiourea or ammonium dithiocarbamate afforded cis-cis-β, β'-thioacrylonitrile (XXI), cis-cis-β, β'-thiocrotononitrile (XXIV) and cis-cis-β, β'-thiocinnamonitrile (XXVI), respectively.