Triphenylphosphine → methyl N-(4-{4-[4-(tert-butoxycarbonyl)piperazin-1-yl]phenyl}-3-methylisoxazol-5-yl)-N-[(2,2,2-trichloroethoxy)carbonyl]leucinate

Participants

Reaction Steps

To tert-butyl 4-[4-(3-methyl-5-{[(2,2,2-trichloroethoxy)carbonyl]amino}isoxazol-4-yl)phenyl]piperazine-1-carboxylate (617 mg, 1.16 mmol), methyl 2-hydroxy-4-methylpentanoate (255 mg, 1.74 mmol) and triphenyl phosphine (460 mg, 1.74 mmol) in dry DMF (15 mL) at 0° C. under dry nitrogen was added diisopropyl azodicarboxylate (0.35 mL, 1.74 mmol) dropwise over ½ hour and the reaction mixture was stirred for 2 days at rt. The reaction was poured into water and the product extracted with Et2O (2×), dried over Na2SO4, concentrated in vacuo and purified by flash chromatography over silica gel (EtOAc/Hex, 25/75) to afford methyl N-(4-{4-[4-(tert-butoxycarbonyl)piperazin-1-yl]phenyl}-3-methylisoxazol-5-yl)-N-[(2,2,2-trichloroethoxy)carbonyl]leucinate.

Provenance & Evidence