Ethanol → (5-bromo-1-trityl-1H-pyrazolo[3,4-b]pyridin-3-yl)methanol

Participants

Reaction Steps

To a solution of methyl 5-bromo-1-trityl-1H-pyrazolo[3,4-b]pyridine-3-carboxylate (XXII) (4.16 Kg, 8.3 mol) in anhydrous THF (62 L) cooled to 10° C. was added anhydrous EtOH (0.97 L, 16.6 mol) and LiBH4 (271 g, 12.5 mol). The reaction was warmed to room temperature and stirred for 24 hours. The solution was concentrated under vacuum to a volume of 4 L then taken up in DCM (80 L). The pH was then adjusted to 8.0 by dropwise addition of aqueous 0.4N HCl (˜280 L). The organic layer was separated and washed with aqueous 25% NaCl (28 L) and then concentrated under vacuum to a volume of 4 L to produce (5-bromo-1-trityl-1H-pyrazolo[3,4-b]pyridin-3-yl)methanol (XXIII) (3.9 Kg, 8.3 mol, 82.3% purity, 100% assay yield). 1H NMR (DMSO-d6, 400 MHz) δ ppm 4.70 (d, J=6 Hz, 2H), 5.49 (t, J=6 Hz, 1H), 7.19 (d, J=7.2 Hz, 5H), 7.20-7.35 (m, 10H), 8.31 (d, J=2.4 Hz, 1H), 8.51 (d, J=2.4 Hz, 1H); ESIMS found C26H20BrN3O m/z 492.0 (M+Na).

Provenance & Evidence