To a stirred solution of pre-tomaymycin (21 mg) in dimethylformamide (0.7 mL), were added potassium carbonate (32 mg), 1-(3-allyloxycarbonylamino-propyloxy)-3,5-bis-(bromomethyl)-benzene (16.2 mg) and potassium iodide (12.8 mg). The reaction was stirred for 20 h at 30° C. Solids were filtered off, washed twice with dimethylformamide (0.2 mL) then discarded. Water (0.5 mL) was added to the combined dimethylformamide solution and the resulting precipitate was filtered off, washed with water and dried by centrifugal evaporation over a Jouan Model RC10.10 apparatus. To the crude compound (27 mg) dissolved in dimethylformamide (0.8 mL), tetrakis(triphenylphosphine) palladium (2 mg), triphenylphosphine (0.9 mg) and pyrrolidine (5.6 μL) were added. After stirring for 15 h at 30° C., tetrakis(triphenylphosphine) palladium (2 mg), triphenylphosphine (1 mg) and pyrrolidine (2.8 μL) were added and the reaction mixture was stirred at room temperature for another 15 h. Water (0.4 mL) was added to the dimethylformamide solution and formic acid was added until complete dissolution of the precipitate. The resulting solution was injected for HPLC purification according to method B1. The appropriate fractions were combined and concentrated by centrifugal evaporation over a Jouan Model RC10.10. apparatus to afford 8,8′-[5-(3-aminopropyloxy)-1,3-benzenediylbis-(methylenoxy)]-bis[(S)-2-eth-(E)-ylidene-7-methoxy-1,2,3,11a-tetrahydro-5H-pyrrolo[2,1-c][1,4]benzodiazepin-5-one] (0.2 mg).
