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 was combined with 2.5 mL of t-butanol and 140 μL of triethylamine was added. Then 129 μL of diphenylphosphoryl azide was added 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 with 1M aqueous sodium bisulfate, aqueous sodium bicarbonate, water, and brine. The ethyl acetate solution was dried with magnesium sulfate and concentrated to give material which was chromatographed on silica gel eluting with an acetone/hexane gradient. Product containing fractions were concentrated to give 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 [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, mp 171.4–175.7° C.

Provenance & Evidence