Sodium Hydroxide → 4-[3-tert-Butyl-5-(2,2,2-trichloro-ethoxycarbonylamino)-pyrazol-1-yl]-piperidine-1-carboxylic acid benzyl ester

Participants

Reaction Steps

To a solution of Intermediate 16b (550 mg, 1.54 mmol) in aqueous NaOH solution (1M, 3.85 mL, 3.85 mmol) and EtOAc (5 mL) at RT, was added 2,2,2-trichloroethyl chloroformate (0.32 mL, 2.31 mmol) over 2 min, then the mixture stirred vigorously for 30 min. The aqueous layer was extracted with EtOAc (10 mL), then the combined organics washed with brine (10 mL), dried (MgSO4), filtered and concentrated in vacuo to leave a yellow-brown oil. FCC, using 0-30% EtOAc in cyclohexane, gave the title compound as a white foam (337 mg, 41%). LCMS (Method 3): Rt 4.81 min, m/z 531, 533 [MH+].

Provenance & Evidence