Vinca alkaloids have been widely used in cancer chemotherapy for over 30 years. 1 Extensive chemistry research has led to several total syntheses, 2 and numerous derivatives have been evaluated, with the aim of improving the therapeutic potency of this class. 3 However, only four drugs are currently available worldwide, namely vinblastine (1a), vincristine (1b), a semisynthetic amide related to vinblastine, vindesine 4 (1c, Scheme 1), and vinorelbine (2, Navelbine).Vinorelbine (2) was obtained in two steps: (1) biomimetic coupling of the two precursor monomers, 5 catharanthine and vindoline, to form 3′,4′-anhydrovinblastine (3), and (2) C′ ring contraction of this intermediate 6 (Scheme 2).In our search for new and more potent vinorelbine derivatives, we were interested in an original chemical approach, which conceivably could induce dramatic changes in the skeleton of the molecule. We decided to investigate the reactivity of these highly functionalized compounds in superacid media. Superacids are able to induce modifications at nonactivated bonds, 7 and in these unusual conditions, indolines and indoles were found stable enough to react with various electrophiles. 8 The effects and reactivity of various electrophiles were investigated. Among these, chloromethanes (CH 2 Cl 2 , CHCl 3 , and CCl 4 ) act as superelectrophiles in HF-SbF 5 , the resulting cations CH 2 Cl + , CHCl 2 + , and CCl 3 + , respectively, exhibiting an extremely reactive hydride-abstracting power. 9Vinorelbine (2) was treated with CCl 4 in HF-SbF 5 at -40 °C. After workup, the main isolated product was identified as

A series of new prodrugs of daunorubicin and doxorubicin which are candidates for antibody-directed enzyme prodrug therapy (ADEPT) is reported. These compounds (25a,b,c and 32a,b,c) have been designed to generate cytotoxic drugs after activation with beta-glucuronidase. As expected, recovery of the active drug was observed after enzymatic cleavage by Escherichia coli beta-glucuronidase as well as by a fusion protein which has been obtained from human beta-glucuronidase and humanized CEA-specific binding region. The six prodrugs are highly stable and are more than 100-fold less cytotoxic than doxorubicin against murine L1210 cell lines. The ortho-substituted phenyl carbamates 25a,b,c are better substrates for beta-glucuronidase than the corresponding para-substituted analogues. After taking into account additional factors such as stability in plasma and kinetics of enzymatic cleavage, we selected the o-nitro prodrug 25c for clinical trials.