L-Proline → (S)-6-bromo-1,2,3,11a-tetrahydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H)-dione

Participants

Reaction Steps

9.2 g (0.038 mol) of 6-bromo-isatoic acid anhydride and 4.6 g (0.040 mol) of L-proline in 55 ml of dimethyl sulphoxide are heated to 70° for 1 hour, the solvent is removed in a high vacuum and the oil obtained is heated to 170° for 15 minutes. The crude product is purified by chromatography on silica gel using a mixture of chloroform and methanol (20:1) for the elution. There is obtained (S)-6-bromo-1,2,3,11a-tetrahydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H)-dione which melts at 221°-224° after recrystallization from chloroform/hexane.

Provenance & Evidence