Dimethylformamide → Methyl 3-chloro-4-formyl-1H-pyrrole-2-carboxylate

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Reaction Steps

DMF (0.579 mL, 1.48 mmol) was cooled to 0° C. under nitrogen. POCl3 (0.647 mL, 6.93 mmol) was added to the cold DMF and stirred at 0 oC, and a solid formed. Dichloroethane (2 mL) was added to the solid followed by the addition of methyl 3-chloro-1H-pyrrole-2-carboxylate (1.00 g, 6.26 mmol) in dichloroethane (2 mL). The reaction mixture was stirred for 10 minutes at 0° C. and heated to reflux until the starting material was no longer evident by TLC. The reaction mixture was cooled and partitioned between EtOAc and water. The organic layer was separated, washed with saturated NaHCO3, dried over MgSO4, filtered and the EtOAc evaporated. Purification was accomplished by silica gel column chromatography (0-30% EtOAc/hexanes) to afford the title compound (0.319 g, 27%), and methyl 3-chloro-5-formyl-1H-pyrrole-2-carboxylate (0.320 g, 27%). 1H NMR (400 MHz, Acetone-d6) δ ppm 11.83 (br. s., 1H), 9.89 (s, 1H), 7.72 (s, 1H), 3.86 (s, 3H). LCMS: m/z=188.2 (M+1).

Provenance & Evidence