SYNTHESIS OF POLYFUSED THIEN0(2,3-b)THIOPHENES PART 2: SYNTHESIS OF THIENOPYRIMIDINE, THIENOTHIAZINE, THIENOPYRROLOPIPRAZINE, AND THIENOTHIAZAPHOSPHOLINE DERIVATIVES

Abstract

3,4-Diamino-2,5-dicarbethoxythieno(2,3b)thiophene (1) was reacted with triethylonhoformate to afford compound 2. The reaction of compounds 2 or 3 with S,S-acetals and N,S-acetals, afforded compounds 4–6. Treatment of compound 1 with 2,5-dimethoxytetrahydrofuran gave the corresponding bipyrrolyl derivative 7, which was reacted with hydrazine hydrate to get the corresponding hydrazide derivative 8. Treating compound 8 with sodium nitrite afforded the corresponding carboazide derivative 9, which in turn cyclized to compound 10. Compound 12 was obtained via the reaction of compound 1 with PhNCS or through treating compound 11 with CS₂ PhNH₂, and KOH. Also, compound 13 was prepared through treatment of compound 12 with Lawesson's reagent or via the reaction of compound 11 with CS, followed by treating the resulting compound 14 with PhNH₂. The reaction of compounds 1 or 3 with Lawesson's reagent gave compound 15. Benzoylation of compound 1 afforded compound 16, which treated with NH₃ gave compound 17. Treatment of compounds 16 or 17 with LR furnished compounds 18 or 19, respectively. The reaction of compound 16 or 17 with P₂S₅ yielded compounds 19 and 20 or 18 and 19, respectively.

Key Words:

• PTC
• 1; 3-Dithiazine
• Lawesson's reagent (LR)
• Thienopyrimidine
• Thienothiazine
• Thienopyrrolopiprazine
• Thienothiazaphospholine Derivatives