u00b0 c for 48 hours 5 0 mmol sodium hydroxide was added to the reaction solution to react for 2 hours after completion of the reaction the solvent was removed by rotary evaporation at 70 u00b0 c followed by recrystallization with acetonitrile water v v 5 1 to obtain pale yellow solid which was dried under vacuum the resultant was recrystallized with dmf once again to obtain a double long carbon chain intermediate r 16 3 the prepared peptide head intermediate fmoc l orn boc oh and an activating agent hatu were dissolved at a molar ratio of 1 2 in a toluene solution and the activation was carried out at room temperature for 2 hours and then a toluene solution of the double long carbon chain intermediate r 16 was added so that the peptide head intermediate reacted with the double long carbon chain intermediate according to a molar ratio of 1 2 followed by amidation reaction at 40 u00b0 c for 48 hours after the reaction was completed the solvent was removed by rotary evaporation at 70 u00b0 c the resultant was dissolved with a solvent of dichloromethane trifluoroacetic acid 2 1 v v and placed at 4 u00b0 c for 1 hour to release the protective group boc then the product was dissolved by a dioxane solvent then 30 ml 10 nahco 3 solvent was added and reacted for 2 hours to remove fmoc group 4 after the product was recrystallized with acetonitrile and then recrystallized with petroleum ether four times the product was dissolved in chloroform and the crude product was purified by a silica gel column and then was eluted with a methanol chloroform volume ratio 3 1 mixed reagent the solvent was removed by.