Potassium bisulfate → (Rac)-4-[3-(tert-butyl-dimethyl-silanyloxy)-1-hydroxymethyl-propyl]-5-oxo-[1,4]diazepane-1-carboxylic acid benzyl ester

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Reaction Conditions

Reaction Steps

A solution of 1.53 g (3.20 mmol) of (rac)-4-[3-(tert-butyl-dimethyl-silanyloxy)-1-methoxycarbonyl-propyl]-5-oxo-[1,4]diazepane-1-carboxylic acid benzyl ester (intermediate 5A) in 32 ml of ethanol was treated at 0° C. with 0.14 g (6.40 mmol) of lithium borohydride. The reaction was stirred 10 min at 0° C. and 1.5 h at room temperature, then neutralized with cold 10% aq. potassium hydrogensulfate solution and extracted with diethyl ether (3×). The organic phases were washed with 10% aq. potassium hydrogensulfate solution, 10% aq. sodium chloride solution, dried over Na2SO4 evaporated to yield 1.29 g (89%) of the title compound as light yellow viscous oil. MS: 451.2 (MH+).

Provenance & Evidence