tert-Butyl piperazine-1-carboxylate → HCID 90014003, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-[6-(4-benzyloxy-2-fluoro-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridin-4-yl]-ethanone (390 mg), acetic acid (25 μL), piperazine-1-carboxylic acid tert-butyl ester (158 mg) and sodium triacetoxy borohydride (270 mg) in dichloromethane (7.5 mL) was stirred at 40° C. overnight. Then additional triacetoxy borohydride (90 mg) was added. The reaction mixture was concentrated in a membrane pump vacuum, and the residue was purified by flash chromatography (silica, heptane/ethyl acetate gradient) giving 4-{1-[6-(4-Benzyloxy-2-fluoro-phenyl)-3-methyl-1-(tetrahydro-pyran-2-yl)-1H-pyrazolo[3,4-b]pyridin-4-yl]-ethyl}-piperazine-1-carboxylic acid tert-butyl ester (90 mg). This material was dissolved in methanol (5 mL), purged with argon, then with hydrogen and palladium (10% on charcoal, 8 mg) was added. The reaction mixture was stirred at 40° C. until the reaction was complete (according to HPLC/MS). The catalyst was filtered off and the filtrate was concentrated in a membrane pump vacuum. The residue was taken up in THF (2 mL), and conc. hydrochloric acid (1 mL) was added. The solution was stirred at r.t., then the solvents were evaporated and the residue was purified by preparative HPLC (C18 column, acetonitrile/water gradient) giving 3-fluoro-4-[3-methyl-4-(1-piperazin-1-yl-ethyl)-1H-pyrazolo[3,4-b]pyridin-6-yl]-phenol (30 mg, 9%).

Provenance & Evidence