Naturally-occurring thiophens. Part IV. Synthesis of some 2,2′-bithienyl derivatives from cuprous acetylides

Abstract

The synthesis of 5-(but-3-en-1-ynyl)-, 5-(but-3-en-1-ynyl)-5′-methyl-, 5-(but-3-en-1-ynyl)-5′-methoxycarbonyl-, 5-(but-3-en-1-ynyl)-5′-hydroxymethyl-, 5-(4-hydroxybut-1-ynyl)-, 5-(prop-1-ynyl)-, 5-(3-formylprop-1-ynyl)-, 5-(3-hydroxyprop-1-ynyl)- and 5-(3-oxobut-1-ynyl)-2,2′-bithienyl from appropriate cuprous acetylides is described.The reactions of 5-iodo-2,2′-bithienyl with cuprous cyanide or thiocyanate to give 5-cyano-2,2′-bithienyl and with cuprous acetate to give 2,2′:5′,2″:5″,2′″-quaterthienyl are included. 2,2-Bithienyl and the 5,5′-dimethyl derivative were prepared from the corresponding Grignard reagents by reaction with cobaltous chloride and the same method was used for 2,2′-bifuran. Some derivatives of this system are described.