Reaction #66052

Reaction equation

diethyl ether

water

(2S)-2-amino-4-pentenoic acid

thionyl chloride

benzyl alcohol

→

title compound

Yield 68.0%

Benzyl (2S)-2-amino-4-pentenoate hydrochloride

Yield 68.0%

Conditions

Workup

1. 1
   ConcentrationThe aqueous layer was concentrated
2. 2
   workup.ADDITIONdiluted with 2M sodium bicarbonate (20 mL)
3. 3
   Extractionextracted with DCM (3×30 mL)
4. 4
   OtherThe combined organic fractions were dried
5. 5
   Otherevaporated
6. 6
   workup.DISSOLUTIONThe crude product dissolved in a minimal volume of MeOH
7. 7
   Otherprecipitated with diethyl ether

Procedure

To a solution of (2S)-2-amino-4-pentenoic acid 17 (225 mg, 1.96 mmol) in benzyl alcohol (5 mL) was added thionyl chloride (2 mL) and the resulting mixture was allowed to stir for 16 h before addition of diethyl ether (30 mL) and extraction with water (3×30 mL). The aqueous layer was concentrated, diluted with 2M sodium bicarbonate (20 mL), and extracted with DCM (3×30 mL). The combined organic fractions were dried and acidified with 1M HCl/diethyl ether (2 mL) and evaporated. The crude product dissolved in a minimal volume of MeOH and precipitated with diethyl ether to yield the title compound (322 mg, 1.34 mmol, 68%) as a white solid. [α]D20−40.6 (c. 0.1, H2O). Mp 186-191° C. 1H NMR (D2O, 300 MHz): δ 7.28 (m, 5H, ArH); 5.51 (m, 1H, H4); 5.11 (m, 4H, H5 and ArCH2); 4.08 (t, J=5.4 Hz, 1H, H2); 2.55 (m, 2H, H3). Mass Spectrum (CI, +ve) m/z 205 (25%) [MH+]. HRMS calcd for C12H16NO2 206.1181, found 206.1169.

Source