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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).

1. temperatureThe mixture is then heated
2. temperatureat reflux 24 hr
3. customthe organic layer is separated
4. customdried
5. customevaporated
6. washChromatography on silica gel, eluting with chloroform-methanol (99:1)