Diisobutylaluminumhydride → [1,6-Diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-5-yl]methanol

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 1,6-diethyl-4-(tetrahydro-2H-pyran-4-ylamino)-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (17.94 g, 51.85 mmol, e.g. which can optionally be as prepared in Intermediate 4) in dichloromethane (150 ml) was cooled to 0° C. under an atmosphere of nitrogen, and was treated with di-iso-butylaluminum hydride (100 ml of a 1.5 M solution in toluene, 150 mmol) added dropwise over 30 minutes, keeping the temperature steady at 0° C. The reaction was stirred at 0° C. for a further 30 minutes after completion of the addition. The reaction was quenched by the dropwise addition of saturated aqueous potassium sodium tartrate solution (120 ml), keeping the temperature below 5° C. The resulting mixture was diluted with ethyl acetate (300 ml) and the whole filtered through a pad of Celite, to form two layers. During this filtration the sinter funnel imploded. Material spilt on the fumehood floor was soaked up and recovered as much as possible. The organic layer was separated and dried (MgSO4), the drying agent was filtered off, and the filtrate evaporated to give a first batch of product. The aqueous layer and the celite were extracted with a larger amount of ethyl acetate to give a second batch of product after evaporation. The two batches of product were combined to give the title compound (14 g) as an off-white waxy solid.

Provenance & Evidence