Methanesulfonic Acid → 8-(3-Amino-3-ethyl-1-azetidinyl)-1-cyclopropyl-7-fluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid methanesulphonate

Participants

Reaction Conditions

Reaction Steps

8-(3-Amino-3-ethyl-1-azetidinyl)-1-cyclopropyl-7-fluoro-4-oxo-1,4-dihydrobenzo[b][1,8]-naphthyridine-3-carboxylic acid methanesulphonate was prepared under the conditions of Example 15, but starting with 1.8 g of 7,8-difluoro-1-cyclopropyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid and 2.94 g of 3-amino-3-ethylazetidine dimethanesulphonate. After recrystallization in dimethylformamide, the product obtained, suspended in 20 cm3 of ethanol, is treated with 3.4 cm3 of a solution at a concentration of 9.6 g % of methanesulphonic acid in ethanol. The suspension is stirred for 5 minutes at approximately 80° C., cooled to a temperature in the region of 20° C., drained and washed with 3 times 10 cm3 of ethanol. 0.55 g of 8-(3-amino-3-ethyl-1-azetidinyl)-1-cyclopropyl-7-fluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid methanesulphonate is obtained in the form of a yellow solid, which decomposes at 248° C.

Provenance & Evidence