Hydrochloric Acid → Tert-butyl 4-[4-(3-methyl-5-{[(2,2,2-trichloroethoxy)carbonyl]amino}isoxazol-4-yl)phenyl]piperazine-1-carboxylate

Participants

Reaction Steps

To tert-butyl 4-[4-(5-amino-3-methylisoxazol-4-yl)phenyl]piperazine-1-carboxylate (900 mg, 2.51 mmol) and DMAP (1.02 g, 8.3 mmol) in CH2Cl2 (25 mL) at 0° C. under dry nitrogen was added 2,2,2-trichloroethyl chloroformate (1.02 g, 8.3 mmol) dropwise and the reaction was warned to rt and stirred for 1 hour. Additional aliquots of DMAP (1.02 g, 8.3 mmol) and 2,2,2-trichloroethyl chloroformate (1.02 g, 8.3 mmol) were added and the reaction mixture was stirred for 2½ hours. Et2O was added and the reaction was poured into aqueous 10% HCl, extracted with Et2O (2×), dried over Na2SO4, concentrated in vacuo and purified by flash chromatography over silica gel (EtOAc/Hex, 3/7) to afford tert-butyl 4-[4-(3-methyl-5-{[(2,2,2-trichloroethoxy)carbonyl]amino}isoxazol-4-yl)phenyl]piperazine-1-carboxylate.

Provenance & Evidence