To a stirred solution of methyl 1-(3,5-bis(hydroxymethyl)phenylamino)-3,6,9,12,15,18,21,24,27,30,33,36-dodecaoxanonatriacontan-39-oate (265c) (67 mg, 0.087 mmol) in anhydrous DMF (1.0 ml) was added iodomethane (7.06 μl, 0.113 mmol) and potassium carbonate (14.47 mg, 0.105 mmol). The reaction was stirred at 82° C. for 18 hours. The mixture was cooled to room temperature, diluted with water and extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. Purification by preparative TLC (10% MeOH/CH2Cl2) gave methyl 2-(3,5-bis(hydroxymethyl)phenyl)-5,8,11,14,17,20,23,26,29,32,35,38-dodecaoxa-2-azahentetracontan-41-oate (265d) (62 mg, 92%). 1H NMR (400 Hz, CDCl3): δ 6.65 (s, 3H), 4.59 (d, J=5.6 Hz, 4H), 3.74 (t, J=6.4 Hz, 2H), 3.67 (s, 3H), 3.61 (m, 46H), 3.54 (t, J=6.0 Hz, 2H) 2.98 (s, 3H), 2.59 (t, J=6.4 Hz, 2H), 2.55 (m, 2H); MS (m/z), found 820.5 (M+K)+.
