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

To a stirred solution of 3 (3.40 g, 22.2 mmol) in CHCl3 (20 mL) at 0° C. was added CF3CO2Ag (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:Et2O/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 (400 MHz, DMSO-d6) δ 13.30 (brs, 1H), 9.52 (s, 1H), 7.04 (s, 1H), and 3.77 (s, 3H); 13C NMR (100 MHz, DMSO-d6) δ 187.13, 160.36, 128.78, 127.79, 115.58, 87.40, and 52.42.

1. filtrationThe reaction mixture was filtered through Celite
2. washthe filtrate was washed with saturated aqueous solution of Na2S2O3 (2×20 mL)
3. dry with materialThe organic layer was dried over anhydrous MgSO4
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customMPLC purification (CH2Cl2:Et2O/95:5) of the residue

ORD record

ord-eb1c79b86d7748e988cf2b6354b535a4

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08404728B2