Lithium Hydroxide → (R)-1-carboxy-2-(3,5-dibromo-4-hydroxy-phenyl)-ethyl 4-(2-oxo-1,2,4,5-tetrahydro-1,3-benzodiazepin-3-yl)-piperidine-1-carboxylate

Participants

Reaction Steps

A solution of 0.51 g (21.3 mmol) LiOH was added to a solution of (R)-2-(3,5-dibromo-4-hydroxy-phenyl)-1-methoxycarbonyl-ethyl 4-(2-oxo-1,2,4,5-tetrahydro-1,3-benzodiazepin-3-yl)-piperidine-1-carboxylate (crude product from Example 128g) in 80 mL THF and the reaction mixture was stirred for 3 h at RT. The THF was eliminated i. vac., the aqueous phase was washed with EtOAc, acidified with 10% HCl and the aqueous phase was extracted exhaustively with EtOAc. The combined organic phases were evaporated down i.vac., suspended in diethyl ether, filtered, the residue was dried and then purified by chromatography (silica gel, DCM/MeOH/AcOH 90:10:1).

Provenance & Evidence