Preparation of polyfunctional aryl azides from aryl triazenes. A new synthesis of ellipticine, 9-methoxyellipticine, isoellipticine, and 7-carbethoxyisoellipticine

(Chemical Equation Presented) The preparation of polyfunctional aryl azides by the reaction of aryl triazenes with NaN₃ in the presence of KHSO₄ or BF₃·OEt₂/TFA (trifluoroacetic acid) has been described. A variety of functional groups (halides, esters, ketones, nitriles, aldehydes, and boronic esters) are tolerated under the Lewis acidic conditions. By using this methodology, the potent antitumor agents, ellipticine and 9-methoxyellipticine, have been synthesized. In addition, isoellipticine and a related derivative, 7-carbethoxyisoellipticine, were also prepared.