Trifluoroacetic acid → Pyrimido(1,6-a)benzimidazole-1,3(2H,5H)-dione, 5-cyclopropyl-8-fluoro-7-(1-piperazinyl)-, mono(trifluoroacetate)

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Reaction Steps

tert-Butyl 4-[5-cyclopropyl-8-fluoro-1,2,3,5-tetrahydro-1,3-dioxopyrimido[1,6-a]benzimidazol-7-yl]-1-piperazinecarboxylate (471 mg, 1 mmol) is dissolved in trifluoroacetic acid (2 ml). After 1 hour at 25° the trifluoroacetic acid is distilled off. The residue is taken up in water (10 ml), treated with sodium hydrogen carbonate (168 mg, 2 mmol) and stirred at 25° for 2 hours. The suspension is cooled to 0°. The crystals are filtered off, washed in succession with in each case 5 ml of cold water and ethanol and recrystallized from ethanol/water (95/5). There are obtained 208 mg (60.6%) of 5-cyclopropyl-8-fluoro-7-(1-piperazinyl)-pyrimido[1,6-a]benzimidazole-1,3(2H,5H)-dione trifluoroacetate.

Provenance & Evidence