Acetic Acid → (RS)-8-(3-benzyl-1-piperazinyl)-7-fluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

HRID 344899Notes

Reaction equation

[CH2:1]([CH:8]1[NH:13][CH2:12][CH2:11][N:10]([C:14]2[C:15]([F:35])=[CH:16][C:17]3[C:18]([CH:34]=2)=[N:19][C:20]2[N:21]([CH3:33])[CH:22]=[C:23]([C:28]([O:30]CC)=[O:29])[C:24](=[O:27])[C:25]=2[CH:26]=3)[CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(O)(=O)C>[OH-].[K+].C(O)C>[CH2:1]([CH:8]1[NH:13][CH2:12][CH2:11][N:10]([C:14]2[C:15]([F:35])=[CH:16][C:17]3[C:18]([CH:34]=2)=[N:19][C:20]2[N:21]([CH3:33])[CH:22]=[C:23]([C:28]([OH:30])=[O:29])[C:24](=[O:27])[C:25]=2[CH:26]=3)[CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 80 °C

Procedure

A suspension of (RS)-8-(3-benzyl-1-piperazinyl)-3-ethoxycarbonyl-7-fluoro-1-methyl-4-oxo-1,4dihydrobenzo[b][1,8]naphthyridine (2.65 g) in N aqueous potassium hydroxide (14 cc) and ethanol (20 cc) is heated to a temperature in the region of 80° C. for 20 minutes, treated at the same temperature with 5% strength acetic acid (32 cc) and stirred for 20 minutes. The insoluble matter is drained at approximately 80° C. and washed with water (2×20 cc), ethanol (2×20 cc) and ethyl ether (2×20 cc). After 2 recrystallizations in dimethylformamide (50 cc each time), (RS)-8-(3-benzyl-1-piperazinyl)-7-fluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (2.05 g) is obtained in the form of a yellow solid, decomposing at 270°-275° C.

Workup

customis drained at approximately 80° C.
washwashed with water (2×20 cc), ethanol (2×20 cc) and ethyl ether (2×20 cc)
customAfter 2 recrystallizations in dimethylformamide (50 cc each time)

Sources & evidence

ORD record: ord-040e5a16ce0e41309ed764b8d0845989
Source dataset: uspto-grants-1991_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05053509

Reaction notes

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