Hydrochloric Acid → 1-Ethyl-6,8-difluoro-1,4-dihydro-7-(4-hydroxypiperazin-1-yl)-4-oxoquinoline-3-carboxylic acid

HRID 1788979

Reaction equation

Cl.Cl.[OH:3][N:4]1[CH2:9][CH2:8][NH:7][CH2:6][CH2:5]1.C(N(CC)CC)C.[CH2:17]([N:19]1[C:28]2[C:23](=[CH:24][C:25]([F:31])=[C:26](F)[C:27]=2[F:29])[C:22](=[O:32])[C:21]([C:33]([OH:35])=[O:34])=[CH:20]1)[CH3:18].Cl>O.CS(C)=O>[CH2:17]([N:19]1[C:28]2[C:23](=[CH:24][C:25]([F:31])=[C:26]([N:7]3[CH2:8][CH2:9][N:4]([OH:3])[CH2:5][CH2:6]3)[C:27]=2[F:29])[C:22](=[O:32])[C:21]([C:33]([OH:35])=[O:34])=[CH:20]1)[CH3:18]

Participants

Conditions

Temperature: 100 °C

Procedure

1-Hydroxypiperazine dihydrochloride (3.94 g) (which is prepared in Preparation 1), triethylamine (21 ml) and dimethylsulfoxide (30 ml) are added to 1-ethyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (4.07 g), which is prepared according to the procedure described in Japanese Patent First Publication No. 30964/1981, and the mixture is heated at 100° C. for 30 minutes. After cooling to room temperature, water (200 ml) is added to the mixture and the pH is adjusted to 7.0 with dil. HCl. The precipitated crystals are filtered, washed with water and dried. The product is recrystallized from a mixture of dimethylformamide and water to yield 1-ethyl-6,8-difluoro-1,4-dihydro-7-(4-hydroxypiperazin-1-yl)-4-oxoquinoline-3-carboxylic acid (4.3 g) as pale yellow needles, m.p. 253°-260° C. (decomposed with foaming) (which starts to color brown at around 234° C.).

Workup

customis prepared
temperatureAfter cooling to room temperature
filtrationThe precipitated crystals are filtered
washwashed with water
customdried
customThe product is recrystallized from a mixture of dimethylformamide and water

Sources & evidence

ORD record: ord-69a2a105fbf243efb1c35a56bb089878
Source dataset: uspto-grants-1987_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04686221

Linked notes

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