Methanol → Methyl 3-benzyl-2-ethyl-7-methylimidazo[4,5-b]pyridine-5-carboxylate

Participants

Reaction Steps

A solution of 440 mg (1.59 mmol) of the product of Step E in H2SO4 (4 mL) and H2O (4 mL) was heated to 80° C. for 8 hours. The reaction was cooled, MeOH (150 mL) was added, then conc NH4OH was added until the mixture turned basic. The white solid (NH4)2SO4 was filtered and washed with MeOH. The water and MeOH were removed in vacuo and and the residue was taken up in MeOH and then filtered to remove any remaining (NH4)2SO4. After concentrating, and removal of water from the residue by evaporation from toluene, anhydrous 3% HCl-MeOH (50 mL) was added and the mixture was stirred overnight at rt. Filtration, concentration, and extraction from 5% aqueous Na2CO3 with CH2Cl2 gave 750 mg of the crude title compound as a solid. 1H NMR (300 MHz, CDCl3, ppm): δ7.93 (s, 1H) 7.38-7.29 (m, 3H), 7.12-7.03 (m, 2H), 5.53 (s, 2H), 3.96 (s, 3H), 2.78 (q, 2H, J=7.5 Hz), 2.70 (s, 3H), 1.29 (t, 3H, J=7.5 Hz).

Provenance & Evidence