Hydrochloric Acid → 1-Cyclopropyl-6-fluoro-7-(3-methyl-1-piperazinyl)5-methyl-4-oxo-1,2,3,4-tetrahydroquinoline

HRID 1073759Notes

Reaction equation

HRID 1073759 reaction equation
[CH:1]1([N:4]2[C:13]3[C:8](=[C:9]([CH3:22])[C:10]([F:21])=[C:11]([N:14]4[CH2:19][CH2:18][NH:17][CH:16]([CH3:20])[CH2:15]4)[CH:12]=3)[C:7](=[O:23])[C:6](C(O)=O)=[CH:5]2)[CH2:3][CH2:2]1.[BH4-].[Na+].Cl>CO>[CH:1]1([N:4]2[C:13]3[C:8](=[C:9]([CH3:22])[C:10]([F:21])=[C:11]([N:14]4[CH2:19][CH2:18][NH:17][CH:16]([CH3:20])[CH2:15]4)[CH:12]=3)[C:7](=[O:23])[CH2:6][CH2:5]2)[CH2:2][CH2:3]1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 72474GrepafloxacinHCID 4311764Sodium borohydride

Product 1

HCID 157127231-Cyclopropyl-6-fluoro-7-(3-methyl-1-piperazinyl)5-methyl-4-oxo-1,2,3,4-tetrahydroquinolineYield 89.2%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

1-Cyclopropyl-6-fluoro-7-(3-methyl-1-piperazinyl)5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (8.0 g) is added to methanol (450 ml), and thereto is added gradually sodium borohydride (3.4 g) with stirring under ice cooling. The mixture is stirred at room temperature for one hour. After the reaction is finished, the reaction mixture is adjusted to about pH 1 with conc. hydrochloric acid and then refluxed for 30 minutes, and thereafter methanol is distilled off under reduced pressure. To the resulting residue is added water, and the mixture is made weakly alkaline with saturated aqueous sodium hydrogen carbonate solution and extracted with chloroform. The chloroform layer is dried over sodium sulfate, and chloroform is distilled off. The resulting residue is purified with silica gel column chromatography (eluent, chloroform → chloroform : methanol =50 : 1) ane then recrystallized from diethyl ether to give 1-cyclopropyl-6-fluoro-7-(3-methyl-1-piperazinyl)-5-methyl-4-oxo-1,2,3,4-tetrahydroquinoline (6.3 g) as yellow prisms, m.p. 98°-100° C.

Workup

  1. stirringThe mixture is stirred at room temperature for one hour
  2. temperaturerefluxed for 30 minutes
  3. distillationmethanol is distilled off under reduced pressure
  4. additionTo the resulting residue is added water
  5. extractionextracted with chloroform
  6. dry with materialThe chloroform layer is dried over sodium sulfate, and chloroform
  7. distillationis distilled off
  8. customThe resulting residue is purified with silica gel column chromatography (eluent, chloroform → chloroform : methanol =50 : 1) ane
  9. customrecrystallized from diethyl ether

Sources & evidence

ORD record
ord-6a03e8075abc44e78ef144ca3a0dc2f3
Source dataset
uspto-grants-1990_11
Patent number
US04971970

Reaction notes

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