Sodium hydride → tert-butyl 6-cyclohexyl-4-(2-methoxy-2-oxoethyl)-4H-thieno[3,2-b]pyrrole-2-carboxylate

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Reaction Steps

tert-Butyl 6-cyclohexyl-4H-thieno[3,2-b]pyrrole-2-carboxylate (1 eq., from Step 1) was dissolved in anhydrous DMF (0.42 M) and sodium hydride (2 eq, 60% suspension in mineral oil) was added. The resulting suspension was stirred at RT for 30 min. Methyl bromoacetate (3 eq.) was then added and the solution was stirred at 50° C. for 1 h. After cooling down, the reaction mixture was diluted with EtOAc and washed sequentially with 1 N hydrochloric acid, saturated NaHCO3 solution and brine, dried over sodium sulfate and evaporated in vacuo. Purification by flash chromatography (PE:EtOAc, 9:1) afforded the title compound (85%). 1H-NMR (400 MHz, DMSO-d6, 300 K, δ) 7.72 (s, 1H), 7.06 (s, 1H), 5.05 (s, 2H), 3.69 (s, 3H), 2.56-2.50 (m, 1H), 1.99-1.67 (m, 5H), 1.52 (s, 9H), 1.43-1.19 (m, 5H). MS (ES+) m/z: 378 [M+H]+.

Provenance & Evidence