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

Participants

Reaction Steps

A mixture of 8-bromo-1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (0.11 g), trans-3-t-butoxycarbonylamino-4-methylpyrrolidine (0.082 g), DBU (0.054 g) and anhydrous acetonitrile (5 ml) was refluxed for 1.5 hours and then concentrated. The resulting residue was dissolved in chloroform (50 ml) and washed with 10% aqueous citric acid solution and water successively. The organic layer was concentrated under reduced pressure and to the oily residue was added methanol to crystallize. The resulting precipitate was collected by filtration, washed with chilled methanol and this was added to concentrated hydrochloric acid-methanol (1:1, 2 ml) and stirred for an hour at room temperature. The reacting mixture was neutralized with concentrated aqueous ammonia, concentrated under reduced pressure and the resulting residue was purified by silica gel column chromatography (chloroform:methanol:concentrated aqueous ammonia=20:6:1) and then recrystallized from dichloromethanemethanol (1:1) to give the title compound (0.04 g) as pale yellow powder, mp 186°-190° C. (decompd.).

Provenance & Evidence