Synthesis Peptide-Chol

Synthesis of Cholesterol-acrylate

To a solution of cholesterol (4 g, 10.3 mmol) and TEA (4.3 mL, 31 mmol) in 50 mL of anhydrous THF, acryloyl chloride (1.3 mL, 15.6 mmol) was mixed with 5 mL of anhydrous THF and added dropwise at 0uC under a positive nitrogen flow. Then the mixture was removed from the ice-bath, warmed up to room temperature, and kept stirring overnight. After the removal of the solvent by rotary evaporator, the crude solid was redissolved in 50 mL of CH2Cl2 , and washed with the following solutions: deionized (DI) water, HCl (0.5 M), DI water, NaHCO 3 (1 M), DI water, and brine. The product in CH2Cl2 was dried over anhydrous MgSO4 overnight, and purified by silica gel column chromatography (CH2Cl2 /Hexane 1/1 v/v) after the removal of the solvent by rotary evaporator. Pure product was obtained as a white solid (yield: 35%).

Synthesis of Cholesterol-peptides

Cholesterol-acrylate and peptide (R5H5, R3H3, R5, or R3) conjugation was carried out in a mixture of DMSO and THF at the presence of TEA. The mixture was stirred at 37uC for 2 days under nitrogen protection. Pure product was obtained by dialysis against deionized water using a molecular weight cut-off of 100–500 D dialysis tube from Spectrum Laboratories (Rancho Dominguez,CA, USA) for one day, followed by freeze-drying.

The best one is  Ch-R3H3 NH2-RRRHHHC-COOH