1,8-Diazabicyclo(5.4.0)undec-7-ene → 7-(cis-3-Amino-4-methyl-1-pyrrolidinyl)-8-bromo-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid

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Reaction Steps

A mixture of 8-bromo-1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (0.19 g), cis-3-t-butoxycarbonylamino-4-methylpyrrolidine (0.14 g), DBU (0.095 g) and anhydrous acetonitrile (5 ml) was refluxed for 2 hours and then concentrated. The resulting residue was dissolved in chloroform (70 ml), washed with 10% aqueous citric acid solution, water successively, dried over anhydrous sodium sulfate and then concentrated. To the resulting oily residue was added hot methanol to crystallize and cooled. The resulting precipitate was collected by filtration, added to the mixture of concentrated hydrochloric acid-methanol (1:1, 3 ml) and stirred for 2.5 hours under elevated temperature. The reaction mixture was neutralized with concentrated aqueous ammonia, the resulting precipitate was collected by filtration, washed with ice-water and recrystallized from dichloromethane-methanol-concentrated aqueous ammonia (10:10:1) to give the title compound (0.06 g) as yellow prisms, mp 225°-226.5° C. (decompd.).

Provenance & Evidence