Reaction #640586

Reaction equation

hydrochloric acid

2-Nitrobenzaldehyde

4-amino-2-methylbutanol

sodium borohydride

→

2-methyl-4-(2-nitrobenzylamino)butanol

Yield 96.2%

Solvents

toluene

Conditions

Workup

1. 1
   Temperatureheated
2. 2
   Temperatureto reflux for two hours with Dean Stark dehydration apparatus
3. 3
   Temperatureto cool
4. 4
   Otherthe solvent was evaporated under reduced pressure
5. 5
   ConcentrationThe obtained concentrate
6. 6
   workup.DISSOLUTIONwas dissolved in methanol (100 ml)
7. 7
   workup.STIRRINGThe reaction mixture was further stirred at room temperature for two hours
8. 8
   Otherthe solvent was evaporated under reduced pressure
9. 9
   workup.ADDITIONWater (30 ml) was added
10. 10
    workup.DISSOLUTIONto dissolve the
11. 11
    Concentrationconcentrate
12. 12
    Extractionafter extracted with ethyl acetate, pH
13. 13
    workup.ADDITIONby added a saturated sodium hydrogen carbonate aqueous solution
14. 14
    Extractionextracted with ethyl acetate
15. 15
    DryingThe organic layer was dried over anhydrous sodium sulfate
16. 16
    Otherthe solvent was evaporated under reduced pressure

Procedure

2-Nitrobenzaldehyde (7.33 g, 48.5 mmol) and 4-amino-2-methylbutanol (5.00 g, 48.5 mmol) were dissolved in toluene (50 ml) and heated to reflux for two hours with Dean Stark dehydration apparatus. After allowed to cool, the solvent was evaporated under reduced pressure. The obtained concentrate was dissolved in methanol (100 ml), added with sodium borohydride (2.75 g, 72.8 mmol) under ice cooled condition and stirred at the same temperature for two hours. The reaction mixture was further stirred at room temperature for two hours, adjusted to pH 4 by adding 1N hydrochloric acid, and the solvent was evaporated under reduced pressure. Water (30 ml) was added to dissolve the concentrate and after extracted with ethyl acetate, pH was adjusted to 8 by added a saturated sodium hydrogen carbonate aqueous solution and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and the solvent was evaporated under reduced pressure to obtain 2-methyl-4-(2-nitrobenzylamino)butanol (11.12 g).

Source