Diisopropylethylamine → rac-[1-({[7-(Benzyloxy)-2,5-dimethylpyrazolo[1,5-a]pyridin-3-yl]carbonyl}amino)-2-methylpentan-2-yl]carbamic Acid tert-butyl Ester

Participants

Reaction Steps

A solution of 240 mg (0.81 mmol) of 7-benzyloxy-2,5-dimethylpyrazolo[1,5-a]pyridine-3-carboxylic acid (Example 139A) in 12 ml of tetrahydrofuran was admixed with 132 mg (0.97 mmol) of 1-hydroxy-7-azabenzotriazole and 186 mg (0.97 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride. The reaction mixture was stirred at room temperature for 10 minutes. The resulting mixture was admixed with 0.422 ml (2.43 mmol) of N,N-diisopropylethylamine and 210 mg (0.97 mmol) of rac-(1-aminomethyl-1-methylbutyl)carbamic acid tert-butyl ester from Example 152A. The mixture was stirred at room temperature for a further 18 hours, and the contents were then concentrated under reduced pressure. The residue was partitioned between dichloromethane and water. The organic phase was removed and washed with water and aqueous sodium chloride solution, dried over sodium sulphate, filtered and concentrated under reduced pressure. The residue was purified by flash chromatography using a prepacked silica gel cartridge (mobile phase: cyclohexane/ethyl acetate, gradient 0% to 50%), which gave 370 mg (65% yield, 71% pure) of the target compound, which was used in the next step without further purification.

Provenance & Evidence