Acetic Acid → 7,9-Difluoro-1-methyl-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid

HRID 981234Notes

Reaction equation

[F:1][C:2]1[C:20](F)=[C:19]([F:22])[C:5]2=[N:6][C:7]3[N:8]([CH3:18])[CH:9]=[C:10]([C:15]([OH:17])=[O:16])[C:11](=[O:14])[C:12]=3[CH:13]=[C:4]2[CH:3]=1.[CH3:23][N:24]1[CH2:29][CH2:28][NH:27][CH2:26][CH2:25]1.O.C(O)(=O)C>CS(C)=O>[F:1][C:2]1[C:20]([N:27]2[CH2:28][CH2:29][N:24]([CH3:23])[CH2:25][CH2:26]2)=[C:19]([F:22])[C:5]2=[N:6][C:7]3[N:8]([CH3:18])[CH:9]=[C:10]([C:15]([OH:17])=[O:16])[C:11](=[O:14])[C:12]=3[CH:13]=[C:4]2[CH:3]=1

Participants

Conditions

Temperature: 80 °C

Procedure

A suspension of 4 g of 7,8,9-trifluoro-1-methyl-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid in 60 cm3 of dimethyl sulphoxide and 3 g of 1-methylpiperazine is heated at 80° C. for 1 hour and a half. After cooling to about 20° C., 150 cm3 of water are added. 18 cm3 of 10% acetic acid are added to the solution obtained. The precipitate formed is drained, washed with 3 times 50 cm3 of water and recrystallized from 50 cm3 of dimethylformamide. 4 g of 7,9-difluoro-1-methyl-8-(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid are obtained in the form of a yellow solid melting at 316° C.

Workup

temperatureAfter cooling to about 20° C.
customobtained
customThe precipitate formed
washwashed with 3 times 50 cm3 of water
customrecrystallized from 50 cm3 of dimethylformamide

Sources & evidence

ORD record: ord-f790a96b01cb4642a927a4f72e8482f1
Source dataset: uspto-grants-1991_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04990515

Reaction notes

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