2 mmol L-Orn was weighted and dissolved in 15 ml of acetonitrile; 16 mmol Boc2O was dissolved in acetonitrile and added dropwise to an acetonitrile solution of ornithine, to react and generate a complex; 10 ml 20% sodium bicarbonate aqueous solution was added, and 2 g of anhydrous sodium carbonate and an appropriate amount of 8-hydroxyquinoline were added in batches; the mixture was stirred and reacted at room temperature for 4 hours to remove copper ions in the complex; then 2 mmol Fmoc-OSu was added to the aforesaid solution, followed by stirring at room temperature for 2 hours; the resultant was recrystallized with an ethyl acetate/petroleum ether mixed solvent, to obtain a peptide head intermediate Fmoc-Orn(Boc)-OH.
