Sodium Hydroxide → {5-tert-Butyl-2-[3-((R)-2-hydroxy-1-methyl-ethoxy)-phenyl]-2H-pyrazol-3-yl}-carbamic acid 2,2,2-trichloro-ethyl ester

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Reaction Steps

A solution of Intermediate 151b (112 mg, 0.39 mmol) in EtOAc (2.1 mL) was treated with aqueous 1N NaOH (0.7 mL, 0.70 mmol) then 2,2,2-trichloroethyl chloroformate (0.056 mL, 0.41 mmol) and the mixture was stirred at RT for 2.5 h. The mixture was treated with another portion of 2,2,2-trichloroethyl chloroformate (0.015 mL, 0.11 mmol) and stirred at RT for a further 1 h. The mixture was diluted with EtOAc and water and the phases were separated. The aqueous layer was extracted with EtOAc (×2) and the combined organic phase was washed with brine, dried (Na2SO4), and concentrated in vacuo to give a pale red gum (195 mg). The gum was purified by FCC, using 0-40% EtOAc in cyclohexane, to give the title compound as a pale golden gum (134 mg, 74%). LCMS (Method 3): Rt 4.15 min, m/z 464.2, 466.2 [MH+].

Provenance & Evidence