Acetic Acid → (R)-4-[3-((S)-4-Hydroxy-6-aza-spiro[2.5]oct-6-yl)-propyl]-2-methyl-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A solution of 0.418 g (1.47 mmol) of (R)-2-methyl-5-oxo-4-(3-oxo-propyl)-[1,4]diazepane-1-carboxylic acid tert-butyl ester (example IC) in 10.5 ml dichloromethane was slowly added to a suspension of 0.241 g (1.47 mmol, 1 eq.) of (S)-6-aza-spiro[2.5]octan-4-ol hydrochloride (intermediate 2), 0.205 ml (1.47, 1 eq.) of triethylamine, 0.168 ml (2.94 mmol, 2 eq.) of acetic acid and 0.353 g (1.62 mmol, 1.1 eq.) of sodium triacetoxyborohydride in 55 ml dichloromethane. After 30 min, the reaction mixture was slowly added to a solution of sat. aq. sodium hydrogencarbonate, followed by extraction with dichloromethane (3 times). The organic phases were washed with a solution of sat. aq. sodium hydrogencarbonate and with 10% aq. sodium chloride solution. The combined organic phases were dried over Na2SO4 and evaporated to give 0.541 g (88%) of the title compound as white foam. MS: 396.3 (MH+).

Provenance & Evidence