Regioselective Acylation of Methyl 2‐Methyl‐4H‐thieno[3,2‐b]pyrrole‐5‐carboxylate.

Abstract

Fused pyrrole derivativesFused pyrrole derivatives R 0160 Regioselective Acylation of Methyl 2-Methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate. -The influence of catalysts, acid chlorides and solvents on the acylation of compound (IVa) is studied in detail. The use of AlCl3 allows the regioselective introduction of the acyl group into position 3, whereas the acyl group is introduced into position 6 of thienopyrrole when SnCl4 is used. -(YAROVENKO*, V. N.; SEMENOV, S. L.; ZAVARZIN, I. V.; IGNATENKO, A. V.; KRAYUSHKIN, M. M.; Russ. Chem. Bull. 52 (2003) 2, 451-456; Zelinsky Inst. Org. Chem., Russ. Acad. Sci., Moscow 117913, Russia; Eng.) -M. Paetzel 41-122

New Sulfanilamide Derivatives Incorporating Heterocyclic Carboxamide Moieties as Carbonic Anhydrase Inhibitors

“…The synthesis of target sulfonamides 7a,c-f and 8a-d,f is presented in Scheme 1 . Intermediate esters were obtained by alkylation of the starting compounds 1 [ 40 ] or 2 [ 41 ] with the appropriate alkyl halides in DMF using sodium hydride as a base. Then, these compounds were used without additional purification to prepare 4-alkyl-4 H -furo[3,2- b ]pyrrole-5-carboxylic acids 3a,c-f and 4-alkyl-4 H -thieno[3,2- b ]pyrrole-5-carboxylic acids 4a-d,f .…”

“…A solution of methyl 4 H -furo[3,2- b ]pyrrole-5-carboxylate 1 (20 mmol) [ 40 ] or methyl 4 H -thieno[3,2- b ]pyrrole-5-carboxylate 2 [ 41 ] in DMF (15 mL) was added dropwise at stirring under inert atmosphere to suspension of sodium hydride (1 g, 25 mmol, prepared from preliminarily washed with anhydrous hexanes 60% suspension of NaH in mineral oil) in DMF (15 mL). The mixture was stirred for 20 min, corresponding alkyl halide (25 mmol) was added, and the mixture was continuously stirred at 45 °C until completion (TLC control by disappearing of initial compound 1 or 2 ).…”