Trifluoroacetic acid → [2-(1-Azido-2-{3-[2-(2,2,2-trifluoroacetylamino)-ethylcarbamoyl]phenoxy}ethoxy)ethoxy]acetic acid ethyl ester

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Reaction Steps

3-[2-Azido-2-(2-ethoxycarbonylmethoxy-ethoxy)-ethoxy]-benzoic acid (0.212 g, 0.6 mmol) was stirred with N,N′-disuccinimidyl carbonate (0.184 g, 0.72 mmol) and DMAP (0.088 g, 0.72 mmol) in dry DMF (1 ml) at room temperature. After 10 minutes, trifluoroacetic acid salt of N-(2-amino-ethyl)-2,2,2-trifluoro-acetamide (0.194 g, 0.72 mmol) was added followed by diisopropylethylamine (DIPEA) (0.251 ml, 1.44 mmol). The reaction mixture was then stirred at room temperature for 17 hours. All the solvents were evaporated under reduced pressure and the residues were partitioned between DCM (50 ml) and aqueous NaH2PO4 (1 N, 50 ml). The aqueous layer was further extracted with DCM (2×25 ml). All the DCM extracts were combined, dried over MgSO4 and evaporated under reduced pressure. The residue was purified by column chromatography (1×20 cm). The title compound, eluted with 1% methanol in DCM, was obtained as an oil (0.255 g, 86.6%). ES-MS, m/z 490.10 (M−1).

Provenance & Evidence