Sodium Hydroxide → 6-((S)-1-(tert-butoxy)-2-ethoxy-2-oxoethyl)-7-(7-fluoro-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylic acid

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Reaction Steps

To a solution of ethyl 6-((S)-1-(tert-butoxy)-2-ethoxy-2-oxoethyl)-7-(7-fluoro-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (130 mg, 0.253 mmol) in EtOH (4 mL) was added 1N NaOH (0.303 mL, 0.303 mmol) and the resulting mixture was stirred at room temp for 4 h. At this point LCMS indicated completion of reaction. The reaction mixture concentrated and the residue diluted with water (3 mL), acidified with 1N HCl, extracted with ethyl acetate (25 mL), washed with brine (10 mL), dried (Na2SO4), filtered and concentrated to afford 6-((S)-1-(tert-butoxy)-2-ethoxy-2-oxoethyl)-7-(7-fluoro-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylic acid (110 mg, 0.226 mmol, 89% yield) as off-white solid (mixture of mono and diacid and also atrope isomers) which was used as is in the next step without further purification. LCMS (M+H)=487.3.

Provenance & Evidence