Diisopropylethylamine → [5-tert-Butyl-2-(3-triisopropylsilanyloxy-phenyl)-2H-pyrazol-3-yl]-carbamic acid 2,2,2-trichloro-ethyl ester

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Reaction Steps

2,2,2-Trichloroethylchloroformate (1.09 mL, 7.92 mmol) was added to a solution of Intermediate 22a (1.53 g, 3.96 mmol) and DIPEA (2.75 mL, 15.8 mmol) in THF (40 mL) at 0° C. The reaction was stirred at RT for 3 h then partitioned between EtOAc and water. The aqueous layer was then extracted with EtOAc (3×). The combined organic layers were washed with brine, dried (MgSO4), filtered and evaporated in vacuo. The residue was purified by FCC, using 0-50% EtOAc in cyclohexane, to give the title compound (2.22 g, 99%). LCMS (Method 4): Rt 5.55 min, m/z 560, 562 [MH+].

Provenance & Evidence