Sodium Carbonate → tert-butyl 6-cyclohexyl-5-(2-formyl-4-methoxyphenyl)-4-(2-methoxy-2-oxoethyl)-4H-thieno[3,2-b]pyrrole-2-carboxylate

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Reaction Steps

tert-Butyl 5-bromo-6-cyclohexyl-4-(2-methoxy-2-oxoethyl)-4H-thieno[3,2-b]pyrrole-2-carboxylate (1 eq., prepared as described in Example 1, Step 3) and 2-formyl-4-methoxyphenylboronic acid (1.5 eq.) were dissolved in dioxane (0.1 M) and treated with 2 M Na2CO3 solution (2 eq.). The solution was degassed by bubbling argon through it and Pd(PPh3)2Cl2 (0.1 eq.) was added. The reaction mixture was heated to reflux for 20 min. After cooling down to RT, the mixture was diluted with EtOAc and washed with 1 N hydrochloric acid and with brine. The organic layer was dried over sodium sulfate and evaporated in vacuo and the residue purified by chromatography (PE:EtOAc, 9:1) to afford the pure title compound (57%) as a solid. 1H-NMR (400 MHz, DMSO-d6, 300 K, δ) 9.64 (s, 1H), 7.89 (s, 1H), 7.43 (s, 1H), 7.41-7.38 (m, 2H), 4.92 (d, J 18.0, 1H), 4.73 (d, J 18.0, 1H), 3.90 (s, 3H), 3.50 (s, 3H), 2.14-2.09 (m, 1H), 1.73-1.19 (m, 10H), 1.54 (s, 9H). MS (ES+) m/z: 534 [M+Na]+.

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