Benzo-diazepine deriv. prepn.

摘要

7-Chloro 1,3-dihydro phenyl-2H 1,4-benzodiazepin-2-one is made by selective elimination of CO2 from carboxylated benzodiazepine in a medium with pH 3 and at 0 deg. C, and subsequent isolation by extraction in aq. medium and chromatography on a silica gel column. - The prod. is purified by extracting with chloroform at pH 8-8.5.