2-Azetidinecarboxylic acid, (S)- → (S)-5,6-difluoro-1,2,4,9,10,10a-hexahydro-azeto[2,1-c][1,4]benzodiazepine-4,10-dione

Participants

Reaction Steps

A solution of 19.6 g (98.4 mmol) of 5,6-difluoro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione and 9.95 g (98.4 mmol) of L-azetidine-2-carboxylic acid in 125 ml of dimethylformamide and 25 ml of acetic acid was stirred at 120° for 16 hours. The brown solution was evaporated and the brown residue obtained was crystallized from ethanol. There were obtained 16 g (68%) of (S)-5,6-difluoro-1,2,4,9,10,10a-hexahydro-azeto[2,1-c][1,4]benzodiazepine-4,10-dione as colourless needles of m.p. >250°.

Provenance & Evidence