SYNTHESIS OF POLYFUSED HETEROCYCLIC SYSTEMS DERIVED FROM FUNCTIONALLY SUBSTITUTED THIENO(2,3-b)THIOPHENE MOEITY

Diethyl 3,4-diaminothieno(2,3-b)thiophene-2,5-dicarboxylate 1 was converted into the sodium salt of the corresponding acid 2. Compound 2 upon treatment with acetic anhydride furnished the bisoxazinone derivative 3. The reaction of compound 3 with ammonium acetate, hydrazine hydrate or aniline afforded the bispyrimidine derivatives 4, 5, or 6 respectively. The reaction of compound 4 with phosphoryl chloride gave the corresponding chloro derivative 7 which was converted into the corresponding hydrazino derivative 8. Treatment of compound 8 with acetylacetone or ethyl acetoacetate gave compounds 9 or 10, respectively. On the other hand, the reaction of compound 1 with hydrazine hydrate gave the corresponding hydrazide derivative 11 which was also treated with acetylacetone, ethyl acetoacetate, formic acid or acetic anhydride to afford the described compounds 12, 13, 14, or 15, respectively.