Trifluoroacetic acid → HCID 86649839, compound

Participants

Reaction Steps

(2-{2-[2-(2-t-Butoxycarbonylaminoethoxy)ethoxycarbonylamino]ethoxy}ethoxycarbonylamino acetic acid ethyl ester (Compound 5, 13.2 g, 0.03 mol, 1 eq) was dissolved in dichloromethane (100 mL) and then stirred. After slowly adding trifluoroacetic acid (150 mL), the mixture was stirred at room temperature for 30 minutes. After removing the solvent, washing 2 times with diethyl ether followed by drying yielded trifluoroacetate of (2-{2-[2-(aminoethoxy)ethoxycarbonylamino]ethoxy}ethoxycarbonylamino)acetic acid ethyl ester (Compound 6, 14.3 g, 99.4%). The trifluoroacetate of (2-{2-[2-(aminoethoxy)ethoxycarbonylamino]ethoxy}ethoxycarbonylamino)acetic acid ethyl ester (Compound 6, 14.1 g, 0.029 mol, 1.5 eq) was dissolved in dichloromethane (200 mL). After sufficiently cooling in an ice bath, triethylamine (28 mL, 0.2 mol, 10 eq) was slowly added for neutralization. Then, previously synthesized 2-(2-(t-butoxycarbonylamino)ethoxy)ethyl 2-(2-((4-nitrophenoxy)carbonyloxy)ethoxy)ethyl carbamate (Compound 4, 10 g, 0.02 mol, 1 eq) was added. After slowly adding triethylamine (5.6 mL, 0.04 mol, 2 eq), the mixture was stirred at room temperature for 3 hours. Then, the reaction mixture was washed 3 times with 1 N HCl aqueous solution (250 mL). The organic layer was separated, dried with magnesium sulfate, and then concentrated. Purification by silica gel column chromatography yielded the target compound ethyl 38,38-dimethyl-4,12,20,28,36-pentaoxo-5,8,13,16,21,24,29,32,37-nonaoxa-3,11,19,27,65-pentaazanonatriacontan-1-oate (Compound 9, 10.2 g, 74%).

Provenance & Evidence