Methyl iodide → 4,6-dichloro-3-methoxy-1-trityl-1H-pyrazolo[4,3-c]pyridine

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Reaction Steps

4,6-dichloro-1H-pyrazolo[4,3-c]pyridin-3(2H)-one (1160 mg, 5.69 mmol) was dissolved in DMF (20 ml), charged with (chloromethanetriyl)tribenzene (1744 mg, 6.25 mmol) followed by sodium hydride (341 mg, 8.53 mmol) and allowed to stir at rt for 1 h. The tritylation was complete by LC/MS. The reaction was charged with potassium carbonate (1572 mg, 11.37 mmol) followed by iodomethane (0.533 ml, 8.53 mmol) and allowed to stir overnight at rt. The alkylation was complete by LC/MS. The reaction was charged with 40 mL water, cooled to 0° C. and the precipitate was filtered and washed 2×20 mL water. The yellow solid was dissolved in 20 mL DCM and poured onto a 100 g Biotage SNAP column and purified 5-25% EtOAc/hexanes to provide 4,6-dichloro-3-methoxy-1-trityl-1H-pyrazolo[4,3-c]pyridine (37B, 1.64 g, 3.56 mmol, 62.7% yield) as a white solid. MS: [M+H]+ m/z 460.

Provenance & Evidence