4-Iodo-2-methoxynicotinaldehyde → 4-[2-(4-Iodo-2-methoxy-pyridin-3-yl)-7-methyl-3H-benzoimidazol-5-yl]-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 4-(3,4-Diamino-5-methyl-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (44.6 mmol—assuming 100% conversion in previous step) in methanol (ca 2700 mL) at 0° C. under a nitrogen atmosphere was slowly added (2 h) via addition funnel, a solution of 4-iodo-2-methoxy-pyridine-3-carbaldehyde (15.0 g, 57.1 mmol) in anhydrous methanol (225 mL). The resulting solution was then stirred at 0° C. for an additional 30 min,. the cooling bath was removed, and the reaction mixture was allowed to stir at room temperature in the presence of air for 72 h. The resulting solution was concentrated in vacuo and the residue was dissolved in dichloromethane (1500 mL) and the solvent removed in vacuo (repeated 3×). The resulting dark foamy solid was dried under high vacuum. 1H NMR (500 MHz, CDCl3) δ 7.82 (d, 1H, J=5.4 Hz), 7.50 (d, 1H, J=5.4 Hz), 6.98 (brs, 1H), 6.90 (brs, 1H), 4.05 (s, 3H), 3.67–3.58 (m, 4H), 3.18–3.09 (m, 4H), 2.63 (s, 3H), 1.49 (s, 9H);. LCMS (M+H)+ m/z 550.

Provenance & Evidence