Reaction #1483095

Reaction equation

pTSA

DL-valine

1-dodecanol

→

Dodecyl 2-amino-3-methylbutanoate

Solvents

toluene

Conditions

Workup

1. 1
   workup.ADDITIONAfter addition
2. 2
   Temperaturethe temperature of the reaction mixture was slowly raised
3. 3
   Temperatureto reflux temperature
4. 4
   Otherthe water was separated azeotropically
5. 5
   ConcentrationThe reaction mixture was concentrated under vacuum
6. 6
   Washwashed with aqueous 5% Na2CO3 (3×50 mL)
7. 7
   DryingThe organic layer was dried over Na2SO4
8. 8
   Concentrationconcentrated under vacuum
9. 9
   Otherto afford
10. 10
    Othercrude 35 (40 g, yield, 82%) as a liquid

Procedure

To a stirred solution of DL-valine 34 (20 g, 170.7 mmol) in toluene (200 mL) was added 1-dodecanol 2 (28.6 g, 153 mmol) in one lot, followed by pTSA (35.7 g, 187.7 mmol). After addition, the temperature of the reaction mixture was slowly raised to reflux temperature and the water was separated azeotropically. The reaction mixture was monitored by TLC. The reaction mixture was concentrated under vacuum. The obtained residue was taken in ethyl acetate (200 mL) and washed with aqueous 5% Na2CO3 (3×50 mL) followed by brine solution. The organic layer was dried over Na2SO4 and concentrated under vacuum to afford crude 35 (40 g, yield, 82%) as a liquid.

Source