Acetic Acid → US10442803, Example 2a

Participants

Reaction Conditions

Reaction Steps

A mixture of di-tert-butyl 1-[2-methyl-1-(phenylsulfonyl)-1H-pyrrolo[3,2-b]pyridin-5-yl]hydrazine-1,2-dicarboxylate (19.53 g, 38.86 mmol, from Step 3) in acetic acid (200 mL) was heated at 120° C. overnight. Precipitate was filtered off, and the filtrate was concentrated in vacuo. Dichloroethane (15 mL) was added, and the suspension was heated at reflux for 15 minutes. Upon cooling to 0° C., the solid product was isolated by filtration and dried at 40° C. under vacuum to give an off-white solid (5.94 g). Solvent was removed from the filtrate in vacuo and the above procedure was repeated using DCE (6 mL) to afford additional solid (3.6 g). Additional product was obtained by flash chromatography of the filtrate, (eluting with a gradient of 0-1% MeOH/DCM containing 1% NH4OH). The chromatography afforded product as a glass, which was recrystallized from MeOH (6 mL). Upon recrystallization, product was isolated as white crystals and air dried (2.19 g). Yield: (11.7 g, 92%).

Provenance & Evidence