Hydrochloric Acid → Boc-Thr(Bzl)-Pro-OH

Participants

Reaction Steps

Substance [5] (52.78 g, 106.29 mM) was dissolved in methanol (300 ml). 1 N NaOH (150 ml, 1.4 molar excess) was added dropwise during 20 minutes with ice cooling and then the mixture was stirred at room temperature. 1 N HCl (43.71 ml, 0.4 molar excess) was added with ice cooling to adjust to pH 7 and methanol was distilled off in vacuo. The aqueous layer was washed with ether (150 ml) and the pH of the aqueous layer was adjusted to pH 3 by adding 1 N HCl (110 ml). The solution was extracted twice with ethyl acetate (300 ml and 150 ml). The extract was dried by adding anhydrous sodium sulfate, then concentrated in vacuo. Ether and hexane were added to the residue to obtain the precipitate. The same operation was repeated and the precipitate was dissolved in ethyl acetate, then dried in vacuo to obtain the foaming solid substance [6] (32.27 g, yield: 77.75%).

Provenance & Evidence