t-Butyl bromide → N-[(phenylmethoxy)carbonyl]-L-tryptophan 1,1-dimethylethyl ester

Participants

Reaction Conditions

Reaction Steps

Into a suspension of N-[(phenylmethoxy)carbonyl]-L-tryptophan (33.27 g; 98.32 mmol), benzyltriethylammonium chloride (BTEAC) (22.4 g; 98.32 mmol) and K2CO3 (176.91 g; 1.28 mol) in dimethylacetamide (750 mL), tert-butyl bromide (265 mL; 2.36 mol) was dropped. The solution was heated to 550° C. and maintained under vigorous stirring for 19 h. The reaction was monitored by HPLC (Chromatographic method of Example 3, A)). The solution was cooled to r.t., diluted with H2O (3 L) and then extracted with EtOAc (2 L). The organic layer was washed with H2O (2 L) and, after elimination of the solvent, N-[(phenylmethoxy)carbonyl]-L-tryptophan 1,1-dimethylethyl ester (36 g) was obtained and used in the following step without further purification.

Provenance & Evidence