Potassium Phosphate, Tribasic → 3-(2-methoxyphenyl)methyl-N-BOC-histidine methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 8 g methanesulfonic anhydride in 45 mL dichloromethane is chilled to -50° C. and treated dropwise with a solution of 6.2 mL 2-methoxybenzyl alcohol, 8.0 mL diisopropylethylamine and 45 mL dichloromethane. The resulting solution is warmed to 0° C. over 30 min and treated dropwise with 15.0 g N,1-bis-BOC-histidine methyl ester dissolved in 45 mL dichloromethane. The mixture is then heated at reflux 24 hr, poured into 400 mL 0.25M, pH=7 potassium phosphate buffer and the organic layer is separated, dried and evaporated. Chromatography on silica gel, eluting with chloroform-methanol (99:1) gives 3-(2-methoxyphenyl)methyl-N-BOC-histidine methyl ester as a gum. NMR (CDCl3) 4.96 (s, 2H, NCH2Ar).

Provenance & Evidence