Water → tert-butyl N-[7-(2-methoxy-4,6-dimethylphenyl)-2-(methylsulfanyl)pyrazolo[1,5-a]pyridin-3-yl]-N-(2-oxetanylmethyl)carbamate

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Reaction Steps

After dissolving tert-butyl N-[7-(2-methoxy-4,6-dimethylphenyl)-2-(methylsulfanyl)pyrazolo[1,5-a]pyridin-3-yl]carbamate (100 mg) in N,N-dimethylformamide (2 mL), sodium hydride (60%, 15 mg) was added while cooling on ice, the mixture was stirred for 30 minutes, 2-oxetanylmethyl 4-methyl-1-benzenesulfonate (70 mg) was added and the mixture was stirred for 1 hour at 40° C. 2-Oxetanylmethyl 4-methyl-1-benzenesulfonate (23 mg) [CAS No. 115845-51-7] and sodium hydride (60%, 5 mg) were again added, and the mixture was stirred for 1 hour. Water was added to the reaction mixture, extraction was performed with ethyl acetate and the extract washed with brine. After drying the obtained organic layer over anhydrous magnesium sulfate and filtering it, the solvent was concentrated under reduced pressure to obtain crude tert-butyl N-[7-(2-methoxy-4,6-dimethylphenyl)-2-(methylsulfanyl)pyrazolo[1,5-a]pyridin-3-yl]-N-(2-oxetanylmethyl)carbamate. This was dissolved in ethyl acetate (2 mL) without purification, a 4 N hydrochloric acid/ethyl acetate solution (1 mL) was added, and the mixture was stirred at room temperature for 1 hour. The reaction mixture was neutralized with 5 N aqueous sodium hydroxide while cooling on ice, and then extraction was performed with ethyl acetate and the organic layer was washed with brine. After drying the obtained organic layer over anhydrous magnesium sulfate and filtering it, the solvent was concentrated under reduced pressure, the residue was purified by silica gel column chromatography, and the title compound (8 mg) was obtained from the n-hexane:ethyl acetate (3:1) fraction as a yellow oil.

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