反应详情

1-Ethyl-7-fluoro-8-[4-(4-fluorobenzyl)piperazin-1-yl]-4-oxo-1,4-dihydrobenzo-[b][1,8]naphthyridine-3-carboxylic acid was prepared under the conditions of Example 2, LAW OFFICES but from 1.6 g of 8-chloro-1-ethyl-7-fluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid and 3.9 g of 4-(4-fluorobenzyl)piperazine. After recrystallizing twice from 20 cm3 of dimethylformamide on each occasion, 1.4 g of 1-ethyl-7-fluoro-8-[4-(4-fluorobenzyl)piperazin-1-yl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid were obtained in the form of a yellow solid melting at about 286-8° C.

1. customAfter recrystallizing twice from 20 cm3 of dimethylformamide on each occasion