Water → (RS)-7-Fluoro-8-[3-(2-furyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

HRID 344914Notes

Reaction equation

C([O:3][C:4]([C:6]1[C:7](=[O:33])[C:8]2[CH:9]=[C:10]3[CH:20]=[C:19]([F:21])[C:18]([N:22]4[CH2:27][CH2:26][NH:25][CH:24]([C:28]5[O:29][CH:30]=[CH:31][CH:32]=5)[CH2:23]4)=[CH:17][C:11]3=[N:12][C:13]=2[N:14]([CH3:16])[CH:15]=1)=[O:5])C.CS(O)(=O)=O.O>[OH-].[K+].C(O)C>[F:21][C:19]1[C:18]([N:22]2[CH2:27][CH2:26][NH:25][CH:24]([C:28]3[O:29][CH:30]=[CH:31][CH:32]=3)[CH2:23]2)=[CH:17][C:11]2=[N:12][C:13]3[N:14]([CH3:16])[CH:15]=[C:6]([C:4]([OH:5])=[O:3])[C:7](=[O:33])[C:8]=3[CH:9]=[C:10]2[CH:20]=1

Participants

Conditions

Temperature: 80 °C

Procedure

A suspension of (RS)-3-ethoxycarbonyl-7-fluoro-8-[3-(2-furyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (1.3 g) in 0.5 N aqueous potassium hydroxide (12 cc) and ethanol (12 cc) is heated for 1 hour to a temperature in the region of 80° C. and then treated at the same temperature with an N aqueous solution (6 cc) of methanesulphonic acid. After cooling to approximately 20° C., the insoluble water is drained, washed with water (3×10 cc), ethanol (3×10 cc) and ethyl ether (3×10 cc) and recrystallized in a mixture of ethanol (13 cc) and dimethylformamide (27 cc). (RS)-7-Fluoro-8-[3-(2-furyl)-1-piperazinyl]-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (0.570 g) obtained in the form of a yellow solid, m.p. 258°-260° C.

Workup

temperatureAfter cooling to approximately 20° C.
washwashed with water (3×10 cc), ethanol (3×10 cc) and ethyl ether (3×10 cc)
customrecrystallized in a mixture of ethanol (13 cc) and dimethylformamide (27 cc)

Sources & evidence

ORD record: ord-32535ec13def4d8d8ba3c767a1a6fd97
Source dataset: uspto-grants-1991_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05053509

Reaction notes

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