Diisopropylethylamine → Boc-proline (p-cyanobenzyl)amide

Participants

Reaction Steps

276 g of Boc-Pro-OSu (0.88 mol) were introduced into 2 l of methylene chloride at 0° C. To this solution were added successively 163.9 g of 4-cyanobenzylamine hydrochloride (0.97 mol) and 230 ml of diisopropylethylamine (1.34 mol). The suspension was stirred in a melting ice bath for 48 h and then filtered. The filtrate was extracted with 20% strength NaHSO4 solution (4×), saturated NaHCO3 solution (3×) and saturated sodium chloride solution (2×), dried and evaporated in a rotary evaporator. Recrystallization of the residue from methyl tert-butyl ether resulted in isolation of 261 g (90%) of white crystals, m.p. 124°-125° C.

Provenance & Evidence