2,3-Heterokondensierte Thiophene aus substituiertem 2-Aminothiophen-3-thiol

2,3-Heterocondensed Thiophenes from Substituted 2-Aminothiophen-3-thiole Ethyl 5-amino-4-mercapto-3-methyl-thiophen-2-carboxylate ( 2 ), obtainable from the appropriate thienylthiocyanate 1 by reduction, undergoes reactions in analogy to the 2-aminobenzenthiole. Thus, with formic acid or trimethylorthoacetat the thieno 2,3-d]thiazoles 4 and 5 are formed. Aromatic aldehydes yield the thieno2,3-d]thiazolines ( 6 ) which can be dehydrogenated by sulphur to form 9 . From carbon disulfide and 2 the thieno2,3-d]thiazol-2-thione ( 7 ) is formed. With phenacylbromide or ethyl bromoacetate 2 can be converted into the thieno3,2-b] thiazine derivatives 11 or 12 . Diazotation of 2 yields the thieno2,3-d]1,2,3-thiadiazole derivative ( 14 ).