Lithium Hydroxide → HCID 86702355, compound

Participants

Reaction Steps

(S)-2-[(S)-2-(tert-Butoxycarbonyl-methyl-amino)-propionylamino]-3-methyl-butyric acid benzyl ester (7 g, 18 mmol) and 1 M aqueous lithium hydroxide (40 mL, 40 mmol) was added to THF/MeOH/H2O (3:1:1; 200 mL) to give a yellow solution. The reaction mixture was stirred at rt overnight and then concentrated in vacuo. The residue was dissolved in water and then acidified to pH 2 using first 6 M and then 1 M aqueous HCl. The mixture was extracted with EtOAc. The organic layer was dried over Na2SO4 and concentrated in vacuo to give crude (S)-2-[(S)-2-(tert-butoxycarbonyl-methyl-amino)-propionylamino]-3-methyl-butyric acid (5.7 g) which was used directly in the next step without further purification, m/z=303 (M+H).

Provenance & Evidence