Réaction #640536

Équation de réaction

N-4-methoxybenzyloxycarbonyl α-methyl β-alanine methyl ester

lithium hydroxide

→

N-4-Methoxybenzyloxycarbonyl α-methyl β-alanine

Rendement 97.3%

Solvants

methanol

Conditions de réaction

Traitement

1. 1
   ConcentrationThe solution was concentrated in vacuo
2. 2
   workup.ADDITIONthe residue taken up in a mixture of water and ether
3. 3
   Autrethe phases separated
4. 4
   Extractionextracted three times with ether
5. 5
   LavageThe combined ethereal phase was washed with saturated aqueous sodium chloride solution
6. 6
   Séchagedried over anhydrous magnesium sulfate
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated in vacuo

Mode opératoire

A solution of N-4-methoxybenzyloxycarbonyl α-methyl β-alanine methyl ester (2.81 g, 10.0 mmol) in 30 mL of 25% aqueous methanol was treated with lithium hydroxide (1.3 equivalents) at room temperature for a period of 2 h. The solution was concentrated in vacuo and the residue taken up in a mixture of water and ether and the phases separated and the organic phase discarded. The aqueous phase was acidified with aqueous potassium hydrogen sulfate to pH=1.5 and then extracted three times with ether. The combined ethereal phase was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to give 2.60 g, 97% of N-4-Methoxybenzyloxycarbonyl α-methyl β-alanine (N-Moz-AMBA) which was purified by recrystallization from a mixture of ethyl acetate and hexane to give 2.44 g, 91% of pure product, mp 96-97° C., MH+=268. 1H NMR (D6-acetone/300 MHz) 1.16 (3H, d, J=7.2Hz), 2.70 (1H, m), 3.31 (2H, m), 3.31 (3H, s), 4.99 (2H, s), 6.92 (2H, 4, J=8.7 Hz), 7.13 (2H, d, J=8.7 Hz).

Source