7,8-Difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid → 7-Fluoro-1-methyl-8-[4-[3-(methylsulfanylmethyl)phenyl]piperazin-1-yl]-4-oxo-benzo[b][1,8]naphthyridine-3-carboxylic acid

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Reaction Steps

7-Fluoro-1-methyl-8-[4-[3-(methylsulphanylmethyl)phenyl]piperazin-1-yl]-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid was prepared under the conditions of Example 1, but from 0.45 g of 7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid and 0.66 g of [3-(methylsulphanylmethyl)phenyl]piperazine in 15 cm3 of dimethyl sulphoxide. After washing 2 times with 15 cm3 of ethanol, 0.61 g of 7-fluoro-1-methyl-8-[4-[3-(methylsulphanylmethyl)phenyl]piperazin-1-yl]-4-oxo-1,4-dihydrobenzo-[b][1,8]naphthyridine-3-carboxylic acid was obtained in the form of a yellow solid melting at about 240-5° C.

Provenance & Evidence