Synthesis of 3,4-biheterylthieno[2,3-b]thiophenes. Part I: Synthesis of 3,4-bi(1 ',3 ',4 '-thiadiazolyl-, s-triazolyl-,1 ',3 ',4 '-thiadiazinyl-, 1 ',3 ',4 '-triazinyl-, thiazolyl-, 1 ',3 '-thiazinyl- and primidinyl)-thieno[2,3-b]thiophenes

摘要

3,4-Diamino-2,5-dicarbethoxythieno[2,3-b]thiophene (1) was allowed to react with NaNO2 and active methylenes to afford the corresponding azo compounds 2a-c. Hydrazonyl chloride 2a was treated with carbon disulfide, phenyl isothiocyanate, benzonitrile, benzyl cyanide, malononitrile, benzalaniline, ethyl mercaptoacetate, and ethyl glycinate to give 1,3,4-thiadiazolyl-, s-triazolyl-, 1,3,4-thiadiazinyl-, 1,3,4-triazinylthieno[2,3-b]thiophenes 3-6 respectively. The reaction of 2b, c with urea, thiourea, and guanidine afforded pyrimidinyl- and thiazinylazothieno [2,3-b]thiophenes 7-10 respectively. Bithiazolylthieno[2,3b]thiophenes 11 and 13 were synthesized by treating compound 1 with CS2 along with halo compounds. The addition of S, S-, N, S-, and N, O-acetals to the Schiff base 14 afforded compounds 15-17 respectively. [References: 17]