Potassium Phosphate, Tribasic → 3-(3-methyl-4-methoxyphenyl)methyl-N-BOC-histidine methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 10.8 g methanesulfonic anhydride in 120 mL dichloromethane is chilled to -50° C. and treated dropwise with a solution of 9.4 g 3-methyl-4-methoxybenzyl alcohol, 10.8 mL diisopropylethylamine and 80 mL dichloromethane. The resulting solution is warmed to -25° C. over 30 min and treated dropwise with 20.0 g N,1-bis-BOC-histidine methyl ester dissolved in 125 mL dichloromethane. The mixture is then allowed to warm to 25° C. over 4 hr, stirring at this temperature 24 hr. The reaction mixture is poured into 700 mL 0.25M, pH=7 potassium phosphate buffer and the organic layer is separated, dried and evaporated. Chromatography on silica gel, eluting with chloroformmethanol (99:1) gives 3-(3-methyl-4-methoxyphenyl)methyl-N-BOC-histidine methyl ester as a gum. NMR (CDCl3) 1.43 (s, 9H, t-Bu).

Provenance & Evidence