Diisopropylcarbodiimide → 5-{2-[(2-tert-Butoxycarbonyl-ethyl)-(17-tert-butoxycarbonyl-heptadecanoyl)-amino]-acetylamino}-isophthalic acid mono-tert-butyl ester

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Reaction Steps

17-[(2-tert-Butoxycarbonyl-ethyl)-carboxymethyl-carbamoyl]-heptadecanoic acid tert-butyl ester (0.130 g) was dissolved in dry DCM (5 ml). HOAt (0.36 mg) and DIC (0.045 ml) was added the mixture was refluxed for 1 h under nitrogen. The reaction mixture was cooled to room temperature and 5-amino-isophthalic acid mono t-Butyl ester (60 mg) was added. After stirring for 1 h DIPEA (0.050 ml) was added, the orange reaction mixture turns yellow. After stirring for 2 days, the reaction mixture was concentrated. The residue was redissolved in EtOAc and extracted with 0.1 N HCl (2×) and brine (1×), dried (Na2SO4), and concentrated to give an sirup, which solidifies on standing. 5-{2-[(2-tert-Butoxycarbonyl-ethyl)-(17-tert-butoxycarbonyl-heptadecanoyl)-amino]-acetylamino}-isophthalic acid mono-tert-butyl ester was obtained in a quantitative yield (214 mg), contaminated with an impurity. HPLC/MS 775 (M), rt 7.64 min.

Provenance & Evidence