Ammonium Chloride → (Rac)-trans-3-(3-fluoropyrazin-2-yl)cyclohexanol

HRID 473688Notes

Reaction equation

HRID 473688 reaction equation
[BH4-].[Na+].[F:3][C:4]1[C:5]([C:10]2[CH2:15][CH2:14][CH2:13][C:12](=[O:16])[CH:11]=2)=[N:6][CH:7]=[CH:8][N:9]=1.[Cl-].[NH4+]>CO>[F:3][C:4]1[C:5]([C@@H:10]2[CH2:15][CH2:14][CH2:13][C@H:12]([OH:16])[CH2:11]2)=[N:6][CH:7]=[CH:8][N:9]=1.[F:3][C:4]1[C:5]([C@H:10]2[CH2:15][CH2:14][CH2:13][C@H:12]([OH:16])[CH2:11]2)=[N:6][CH:7]=[CH:8][N:9]=1

Participants

6

Reactant 3

HCID 25517Ammonium ChlorideHCID 4311764Sodium borohydrideHCID 593514053-(3-Fluoropyrazin-2-yl)cyclohex-2-enone

Product 2

HCID 59351407(Rac)-trans-3-(3-fluoropyrazin-2-yl)cyclohexanolHCID 66986535(Rac)-cis-3-(3-fluoropyrazin-2-yl)cyclohexanol

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Sodium borohydride (295 mg, 7.80 mmol) was added was added portion wise to a solution of 3-(3-fluoropyrazin-2-yl)cyclohex-2-enone (500 mg, 2.60 mmol) in MeOH (15 ml) at RT. After completion of the addition the reaction mixture was stirred at RT for 30 minutes. It was then cooled in an ice-water bath, saturated aqueous ammonium chloride (25 ml) was added drop wise, and the resulting mixture was extracted with EtOAc (2×100 ml). The combined organic layers were washed with brine and dried over sodium sulfate. Filtration and concentration under reduced pressure, followed by flash chromatography on silica gel (0% to 20% EtOAc in hexanes) afforded (rac)-cis-3-(3-fluoropyrazin-2-yl)cyclohexanol and (rac)-trans-3-(3-fluoropyrazin-2-yl)cyclohexanol as colorless oils. MS (ESI, pos. ion) m/z: 197.0 (M+1) and MS (ESI, pos. ion) m/z: 197.0 (M+1), respectively.

Workup

  1. additionAfter completion of the addition the reaction mixture
  2. temperatureIt was then cooled in an ice-water bath
  3. extractionthe resulting mixture was extracted with EtOAc (2×100 ml)
  4. washThe combined organic layers were washed with brine
  5. dry with materialdried over sodium sulfate
  6. filtrationFiltration and concentration under reduced pressure

Sources & evidence

ORD record
ord-93ff685c556448b88fe9e619127b4d18
Source dataset
uspto-grants-2014_01
Patent number
US08637500B2

Reaction notes

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