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Synthesis and antitumor evaluation of some new derivatives and fused heterocyclic compounds derived from thieno[2,3‐b]pyridine: Part 2

“…Scheme 6 involves the synthesis of spiro (thienopyrimidin-4-one) derivative 38 through the reaction of carboxamide compound [19] 37 with cyclohexanone in glacial acetic acid. [49,50] The 1 H NMR spectrum of compound 38 displayed multiplet and two triplet signals at δ 1.20 to 1.30, 1.55, and 1.72 ppm attributed to cyclohexyl-C 4 , cyclohexyl-C 3,5 , and cyclohexyl-C 2,6 protons, respectively. The proposed mechanism for the synthesis of compound 38 is illustrated in Figure 5.…”

Synthesis of derivatives of a new heterocyclic systems — 7-thia-5,8,11-triazaindeno[1,2-c]fluorene

“…In a continuation of our investigations in the field of synthesis of condensed thienopyridines [2] we decided to study the possibility of polycyclic products under conditions of cyclocondensation of phthalic anhydride with thieno[2,3-b]pyridine 1, which is readily prepared from the thiolate 2 and α-chloroacetamide under ThorpeZiegler conditions [3]. It was established that in boiling AcOH the reaction stopped at the stage of the formation of the 3-phthalimido derivative 3 in 81% yield, whereas in boiling DMF a deeper condensation occurred to give a derivative of a new heterocyclic system -7-thia-5,8,11c-triazindeno [ Evidently the temperature and the low solubility of compound 3 in AcOH have an important influence on the course of the condensation process.…”

“…3-Amino-6-oxo-4-phenyl-4,5,6,7-tetrahydrothieno[2,3-b]pyridine-2-carboxamide (1) was obtained by a modified procedure [3]: 10% KOH (15.7 ml, 30 mmol) was added to a solution of thiolate 2 (10 g, 30 mmol) in DMF (30 ml), and stirred with heating until solution was complete. The mixture was filtered to α-chloroacetamide (3.0 g, 32 mmol) in DMF (5 ml), heated to boiling, stirred at ~50°C for 3 h, kept over night, then more 10% KOH (15.7 ml) was added, boiled for 5 min, kept for 2 d, and then diluted with water (200 ml).…”