Citric Acid → trans-2-[N'-(6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carbonyl)-hydrazinocarbonyl]-(S)-pyrrolidin-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a clear solution of trans-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid (15 gm, 0.054 mol) in N,N-dimethyl formamide (150 ml), was added EDC hydrochloride (15.57 gm, 0.082 mol) followed by HOBt (11.0 gm, 0.082 mol) at about 25° C. to 35° C. under stirring. The reaction mixture was stirred for 15 minutes and a solution of (S)—N-tert-butoxycarbonyl-pyrrolidin-2-carboxylic acid hydrazide (14.93 gm, 0.065 mol) dissolved in N,N-dimethyl formamide (75 ml), followed by N,N-di-isopropyl ethylamine (28.4 ml, 0.163 mol) were added. The reaction mixture was stirred at a temperature between 25° C. to 35° C. for 16 hours. The reaction mixture was poured under stirring into 10% aqueous citric acid solution (2250 ml). The resulting mixture was extracted with diethyl ether (1000 ml×3). Combined organic layer was washed with water (1000 ml) followed by brine solution (500 ml) and dried over sodium sulfate. Concentration of organic layer under vacuum afforded the crude residue in 13 gm quantity. The residue was purified using silica gel column chromatography to provide the product (trans-2-[N′-(6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carbonyl)-hydrazinocarbonyl]-(S)-pyrrolidin-1-carboxylic acid tert-butyl ester) in 6.3 gm quantity as a white powder.

Provenance & Evidence