Benzyl chloroformate → 1,2,3,5-Tetrahydro-benzo[e][1,4]diazepine-4-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

2,3,4,5-Tetrahydro-1H benzo[e][1,4]diazepine (5 g, 33.7 mmol) was dissolved in THF (168.5 mL and cooled to 0° C. with an ice bath. Hunig's base (8.81 mL, 50.6 mmol) and benzyl chloroformate (5.30 mL, 37.1 mmol) was added dropwise with stirring. After 7 hours stirring, THF was removed, and water and ethyl ether were added to the flask. The reaction mixture was extracted with diethyl ether (4×), and the combined organic extracts were washed with aqueous sodium bicarbonate (1×) and brine (1×). The organic extracts were then dried with magnesium sulfate, filtered and concentrated to give a yellow oil. Further purification (25:75 ethyl acetate/hexane, then 30:70 ethyl acetate/hexane) yielded 7.9 g of desired product (83%).

Provenance & Evidence