tert-Butanol → [7-(2-chloro-4,6-dimethylphenyl)-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridin-3-yl]carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A 159 mg sample of 7-(2-chloro-4,6-dimethylphenyl)-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine-3-carboxylic acid (5-1) was combined with 2.5 mL of t-butanol and 140 μL of triethylamine was added. To this mixture was added 129 μL of diphenylphosphoryl azide and the reaction mixture was heated to 85° C. for 2 h. After cooling to room temperature, the reaction mixture was dissolved in ethyl acetate and washed sequentially with 1M aqueous sodium bisulfate, aqueous sodium bicarbonate, water, and brine. The ethyl acetate solution was dried with magnesium sulfate and concentrated. The crude product was flash chromatographed on silica gel eluting with an acetone/hexane gradient to afford a solid residue which was slurried in a small amount of boiling hexane. After the mixture cooled to room temperature, the solids were collected by filtration to provide 71 mg of 5-3: mp 171.4-175.7° C.

Provenance & Evidence