L-Proline → (S)-6,7-dichloro-1,2,3,11a-tetrahydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H)-dione

Participants

Reaction Steps

A mixture of 22 g (94.8 mmol) of 5,6-dichloroisatoic acid anhydride, 10.85 g (94.8 mmol) of L-proline and 100 ml of dimethyl sulphoxide is heated to 90° for 0.5 hour, subsequently evaporated to dryness in a high vacuum and the residue is heated to 150° for 1 hour. By chromatography on silica gel while eluting with ethyl acetate and subsequent crystallization from ethyl acetate and hexane there is obtained (S)-6,7-dichloro-1,2,3,11a-tetrahydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H)-dione of melting point 203°-205° C.

Provenance & Evidence