Reaction #1483097

Reaction equation

pTSA

DL-leucine

1-dodecanol

→

43

Yield 102.2%

dodecyl 2-amino-4-methylpentanoate

Yield 102.2%

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

Procedure

To a stirred solution of DL-leucine 42 (20 g, 152 mmol) in toluene (400 mL) was added 1-dodecanol 2 (25.56 g, 137.2 mmol) in one lot, followed by pTSA (31.9 g, 167.7 mmol). After addition, the temperature of the reaction mixture was slowly raised to reflux temperature, the water was separated azeotropically, and 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 43 (42 g, yield: 91.9%) as a liquid.

Source