Trifluoroacetic acid → HCID 131732147, compound

Participants

Reaction Steps

Doxorubicin was obtained from Sigma-Aldrich. To couple digoxygenin to doxorubicin, we performed the following procedure: To a solution of Digoxigenin-3-O-methylcarbonyl-epsilon-aminocaproic acid-N-hydroxysuccinimide ester (20 mg, 30.4 μmol) in DMF (500 μL) was added triethylamine (8.4 μL, 60.8 μmol) and the resulting mixture was transferred immediately to a solution of Doxorubicin-HCl (16.6 mg, 30.4 μmol) in DMF (500 μL). The reaction mixture was tumbled for 2 h at ambient temperature, filtered, and the target compound was isolated by preparative reversed phase HPLC employing an acetonitrile/water gradient containing 0.1% TFA (Merck Cromolith prep RP-18e column, 100×25 mm). After lyophilization the Doxorubicin-Digoxigenin conjugate was obtained as a colorless solid (25.2 mg, 76%). Analytical HPLC: tR=13.9 min (Merck Chromolith Performance RP-18e, 100×4.6 mm, water+0.1% TFA acetonitrile/water+0.1% TFA 80:20, 25 min); ESI-MS (positive ion mode): m/z: calcd for C58H75N2O18: 1087.5; found: 1087.6 [M+H]+. The molecular weight of doxorubicin is 579.98 Da. The molecular weight of the resulting Doxorubicin-Dig conjugate is 1087.24 Da. Until the point of complexation to the antibody, we stored the conjugate in aliquots in DMSOat −20° C. FIG. 18 shows the structure of Doxorubicin-digoxygenin conjugate.

Provenance & Evidence