Sodium borohydride → 2-Cyclopentyl-1,2,3,4-tetrahydroquinoline

HRID 500452Notes

Reaction equation

HRID 500452 reaction equation
[CH:1]1([C:6]2[CH:15]=[CH:14][C:13]3[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=3)[N:7]=2)[CH2:5][CH2:4][CH2:3][CH2:2]1.[BH4-].[Na+]>CO.O.O.O.O.O.O.[Ni](Cl)Cl>[CH:1]1([CH:6]2[CH2:15][CH2:14][C:13]3[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=3)[NH:7]2)[CH2:2][CH2:3][CH2:4][CH2:5]1

Participants

5

Reactant 2

HCID 4311764Sodium borohydrideHCID 218264322-Cyclopentylquinoline

Product 1

HCID 650418282-Cyclopentyl-1,2,3,4-tetrahydroquinolineYield 92.1%

Reagents, catalysts & solvents 2

HCID 11791229Dichloronickel;hexahydrateCatalystHCID 887MethanolSolvent

Procedure

To a solution of 2-cyclopentylquinoline (7.95 g, 40.3 mmol) and nickel (II) chloride hexahydrate (1.63 g, 6.85 mmol) in methanol (120 ml) cooled in an ice/methanol bath was added sodium borohydride (6.1 g, 161.2 mmol) portionwise over 1.5 h. The cooling bath was removed and the reaction stirred for a further 30 minutes. The methanol was then removed in vacuo. To the resulting black precipitate was added 2 M hydrochloric acid (100 ml) and then basified with 10 M potassium hydroxide. The mixture was poured into a separating funnel and extracted with ether (4×200 ml). The combined organic layers were dried (MgSO4), filtered and the solvent removed in vacuo to give 2-cyclopentyl-1,2,3,4-tetrahydroquinoline (7.45 g, 37.1 mmol) as a light brown oil.

Workup

  1. customThe cooling bath was removed
  2. customThe methanol was then removed in vacuo
  3. additionTo the resulting black precipitate was added 2 M hydrochloric acid (100 ml)
  4. additionThe mixture was poured into a separating funnel
  5. extractionextracted with ether (4×200 ml)
  6. dry with materialThe combined organic layers were dried (MgSO4)
  7. filtrationfiltered
  8. customthe solvent removed in vacuo

Sources & evidence

ORD record
ord-3f234ec8a24c428ebc70d0e2e9896d2f
Source dataset
uspto-grants-2010_08
Patent number
US07772227B2

Reaction notes

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