Carbonazidic acid, 1,1-dimethylethyl ester → 2-(Benzyl(tert-butoxycarbonyl)amino)acetic acid

Participants

Reaction Steps

N-Benzylglycine hydrochloride (7.38 g, 36.6 mmol), tert-butyl azidoformate (10.7 mL, 73.2 mmol) and sodium bicarbonate (12.3 g) were reacted in 150 mL dioxane/H2O-1:1 (v/v) at 45° (24 hr) and then at room temperature (24 h). The reaction suspension was evaporated to dryness and the resulting white residue was dissolved in 200 mL glacial acetic acid/H2O--1:1(v/v) with cooling to 4°. Water (800 ml) was slowly added with rapid stirring and cooling. The resulting turbid solution was seeded with Boc-N-benzyl-glycine obtained from Method A and allowed to stand in an ice bath for 30 min. The resulting material was gathered by filtration, washed with water followed by petroleum ether (bp 30°-75°) and dried to give 8.34 g (86%) of crude product as a white solid. Recrystallization from dichloromethane petroleum ether (bp 30°-75°) gave 7.34 g (76%) of white, crystalline product identical to Boc-N-benzylglycine (Method A) by NMR and melting point (106°).

Provenance & Evidence