Dimethylformamide → (S)-7-fluoro-12,12a-dihydro-1-(3-phthalimidomethyl-1,2,4-oxadiazol-5-yl)-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepin-9-one

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Reaction Steps

20 g (69.6 mmol) of (S)-7-fluoro-12,12a-dihydro-9-oxo-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]-benzodiazepine-1-carboxylic acid were dissolved in 40 ml of N,N-dimethylformamide, treated portionwise with 13 g (80.2 mmol) of 1,1'-carbonyldiimidazole and stirred at 60° for 10 min. After adding 16.78 g (76.6 mmol) of phthaloylglycine amidoxime a mixture was stirred at 90° for 1 hour, 14 ml of trifluoroacetic acid were added and the mixture was stirred at 85° for a further 18 hours. The suspension obtained was cooled, the crystals were filtered off and rinsed with methanol. There were obtained 16.74 g (51%) of (S)-7-fluoro-12,12a-dihydro-1-(3-phthalimidomethyl-1,2,4-oxadiazol-5-yl)-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepin-9-one of m.p. 287°-288°, which was used in the next step without further crystallization.

Provenance & Evidence