Iodine → Methyl 4-formyl-5-iodo-1H-pyrrole-2-carboxylate

Participants

Reaction Steps

To a stirred solution of 3 (3.40 g, 22.2 mmol) in CHCl3 (20 mL) at 0° C. was added CF3COOAg (5.40 g, 24.4 mmol) followed by I2 (3.10 g, 24.4 mmol). The resulting mixture was stirred for 16 hours in the dark at room temperature. The reaction mixture was filtered through Celite and the filtrate was washed with saturated aqueous solution of Na2S2O3 (2×20 mL). The organic layer was dried over anhydrous MgSO4, filtered and concentrated in vacuo. MPLC purification (CH2Cl2:diethyl ether/95:5) of the residue gave 4 as a white solid (0.72 g, 32% based on the recovered starting material). Along with 4, two minor compounds methyl-4-formyl-5-iodo-1H-pyrrole-2-carboxylate, methyl 4-formyl-3,5-diiodo-1H-pyrrole-2-carboxylate and the starting material 3 were also isolated. 1H NMR (DMSO-d6) δ 13.30 (bs, 1H), 9.52 (s, 1H), 7.04 (s, 1H), and 3.77 (s, 3H); 13C NMR (DMSO-d6) δ 187.13, 160.36, 128.78, 127.79, 115.58, 87.40, and 52.42.

Provenance & Evidence