Exceedingly facile one-pot protocols to the synthesis of pyrimido annulated analogues of carbazolo condensed azepinones and their evaluation for analgesic activity

Abstract

Extremely simple protocols based on the reactivity of corresponding oxoketenedithioacetal (4), 2-(dimethylaminomethylene) ketone (5), β-oxoenolether (6) and α,β-unsaturated ketone (7) derivatives of 7-ethyl-3, 4-dihydroazepino[3,2-b]carbazol-2,5(1H,7H)-dione (3) have been developed to provide an easy access to their pyrimido annulated analogues (8-15) of medicinal interest. The key compound 3 from which, the synthesis proceeded has been realized in two steps from the commercial 3-amino-9-ethyl carbazole (1) on its reaction in the first step with ethyl succinyl chloride followed by cyclocondensation of the resulting ester 2 with PPA. The selected synthesized compounds were screened for in-vivo analgesic activity using acetic acid induced writhing model in mice. Among them, compound 13was found to be most active and found comparable to standard aspirin.

Keywords

• 3-Amino-9-ethyl carbazole
• Oxoketnedithioacetal
• Dimethyl formamide dimethyl acetal
• 2-(Dimethylaminomethylene)ketone
• Oxoenolether
• Chalcone