Phe-Gly (manufactured and sold by PEPTIDE INSTITUTE INC., Japan, 1.1 g, 5 mmol) was dissolved in a 10 mixture of 2 ml of H2O, 2 ml of 2-propanol and 1.5 ml of diethylamine, to thereby obtain a solution. To the obtained solution was portionwise added trityl chloride (1.8 g, 6.5 mmol), followed by stirring for one hour. To the resultant reaction mixture was added H2O, to thereby generate a precipitate. The generated precipitate was collected, washed with water and then dissolved into 5 ml of acetic acid, to thereby obtain an acidic solution. The obtained acidic solution was evaporated to dryness under reduced pressure, to thereby obtain 1.5 g of Trt-Phe-Gly.
