Acetic Acid → (RS)-7,9-difluoro-1-methyl-4-oxo-8-(3-phenyl-1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid

HRID 344881Notes

Reaction equation

C([O:3][C:4]([C:6]1[C:7](=[O:35])[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[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=5)[CH2:23]4)=[C:17]([F:34])[C:11]3=[N:12][C:13]=2[N:14]([CH3:16])[CH:15]=1)=[O:5])C.[OH-].[K+].C(O)(=O)C>C(O)C>[F:21][C:19]1[C:18]([N:22]2[CH2:27][CH2:26][NH:25][CH:24]([C:28]3[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=3)[CH2:23]2)=[C:17]([F:34])[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:35])[C:8]=3[CH:9]=[C:10]2[CH:20]=1

Participants

Conditions

Temperature: 75 °C

Procedure

A suspension of (RS)-3-ethoxycarbonyl-7,9-difluoro-1-methyl-4-oxo-8-(3-phenyl-1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine (2 g) in ethanol (25 cc) and N aqueous potassium hydroxide (15 cc) is heated with stirring to a temperature in the region of 75° C. for 2 hours. The solution obtained, at approximately 75° C., is treated with 10% strength aqueous acetic acid solution (9 g). The insoluble matter obtained is drained at a temperature in the region of 75° C. and washed with water (3×30 cc) at approximately 20° C. After 1 recrystallization in dimethylformamide (40 cc), (RS)-7,9-difluoro-1-methyl-4-oxo-8-(3-phenyl-1-piperazinyl)-1,4-dihydrobenzo[b][1,8]naphthyridine-3-carboxylic acid (1.5 g) is obtained in the form of an orange-colored solid, m.p. 298° C.

Workup

temperatureis heated
customThe solution obtained, at approximately 75° C.
customThe insoluble matter obtained
customis drained at a temperature in the region of 75° C.
washwashed with water (3×30 cc) at approximately 20° C
customAfter 1 recrystallization in dimethylformamide (40 cc)

Sources & evidence

ORD record: ord-447c60e6fc864a3aa8b43ccc96cad07b
Source dataset: uspto-grants-1991_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05053509

Reaction notes

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