Reaction #1379891

Reaction equation

5-aminoquinoline

acetaldehyde

4-thiocresol

→

yellow solid

Yield 62.7%

ethylquinolin-5-yl-amine

Yield 62.7%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperatureat reflux for 4 h
2. 2
   OtherThe reaction mixture was evaporated under reduced pressure
3. 3
   workup.DISSOLUTIONthe residue dissolved in ethanol (100 ml)
4. 4
   workup.ADDITIONSodium borohydride (10 g) was then added to the reaction mixture in portions
5. 5
   Temperaturemaintaining the temperature below 5° C
6. 6
   workup.STIRRINGThis reaction mixture was stirred
7. 7
   Temperatureat reflux for 2 h
8. 8
   workup.ADDITIONWater (40 ml) was then added
9. 9
   workup.STIRRINGthe mixture was stirred for a further 25 min
10. 10
    Temperatureat reflux
11. 11
    Extractionthe product was extracted with dichloromethane (4×100 ml)
12. 12
    Washwashed with water (250 ml)
13. 13
    Dryingbefore being dried over MgSO4
14. 14
    OtherThe solvent was then removed under reduced pressure
15. 15
    Otherthe residue was purified by column chromatography on silica gel eluting with ethyl acetate in hexane
16. 16
    OtherThe solvent in the eluent was evaporated

Procedure

A mixture of 5-aminoquinoline (7.2 g, 0.05 mol), acetaldehyde (2.6 g, 0.06 mol) and 4-thiocresol (6.8 g, 0.055 mol) in ethanol (100 ml) was stirred at reflux for 4 h. The reaction mixture was evaporated under reduced pressure and the residue dissolved in ethanol (100 ml). Sodium borohydride (10 g) was then added to the reaction mixture in portions maintaining the temperature below 5° C. This reaction mixture was stirred at reflux for 2 h and cooled to room temperature. Water (40 ml) was then added and the mixture was stirred for a further 25 min at reflux. The pH of the mixture was then adjusted to pH8 with 2N NaOH and the product was extracted with dichloromethane (4×100 ml). The dichloromethane extracts were combined and washed with water (250 ml) before being dried over MgSO4. The solvent was then removed under reduced pressure and the residue was purified by column chromatography on silica gel eluting with ethyl acetate in hexane. The solvent in the eluent was evaporated to give 5.4 g of a yellow solid which was used without further purification.

Source