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Next-generation taxoids, such as SB-T-1214, are highly potent cytotoxic agents that exhibit remarkable efficacy against drug-resistant tumors in vivo, including those that overexpress the P-glycoprotein (Pgp) efflux pump. As SB-T-1214 is not a substrate for Pgp-mediated efflux, it may exhibit a markedly different biodistribution and tumor-accumulation profile than paclitaxel or docetaxel, which are both Pgp substrates. To investigate the biodistribution and tumor-accumulation levels of SB-T-1214 using positron emission tomography (PET), a new synthetic route has been developed to allow the incorporation of 11C, a commonly employed positron-emitting radionucleide, via methyl iodide at the last step of chemical synthesis. This synthetic route features a highly stereoselective chiral ester enolate–imine cyclocondensation, regioselective hydrostannation of the resulting β-lactam, and the Stille coupling of the novel vinylstannyl taxoid intermediate with methyl iodide. Conditions have been established to allow...

Novel C-8a functionalized tricyclic compounds having cyano enones in rings A and C have been synthesized and biologically evaluated. Among them, compounds with acetylene groups at C-8a show extremely high potency in in vitro and in vivo bioassays for anti-inflammatory and cytoprotective activities. Both in vitro and in vivo potencies are markedly higher than those of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), which is being evaluated as an anticancer drug in phase I clinical trials.

We initially randomly synthesized about 60 oleanane and ursane triterpenoids as potential anti-inflammatory and cancer chemopreventive agents. Preliminary screening of these derivatives for inhibition of production of nitric oxide induced by interferon-gamma in mouse macrophages revealed that 3-oxooleana-1, 12-dien-28-oic acid (B-15) showed significant activity (IC(50) = 5.6 microM). On the basis of the structure of B-15, 19 novel olean- and urs-12-ene triterpenoids with a 1-en-3-one functionality having a substituent at C-2 in ring A have been designed and synthesized. Among them, 3-oxooleana-1,12-diene derivatives with carboxyl, methoxycarbonyl, and nitrile groups at C-2 showed higher activity than the lead compound B-15. In particular, 2-carboxy-3-oxooleana-1, 12-dien-28-oic acid (3) had the highest activity (IC(50) = 0.07 microM) in this group of triterpenoids. The potency of 3 was similar to that of hydrocortisone (IC(50) = 0.01 microM), although 3 does not act through the glucocorticoid receptor. Interesting structure-activity relationships of these novel synthetic triterpenoids are also discussed.

A series of ellipticine glycosides [2-N-glycosyl quaternary pyridinium salts of three ellipticines: ellipticine (1), 9-methoxyellipticine (2), and 9-hydroxyellipticine (4)] were stereoselectively synthesized in good yields by an improved condensation reaction between ellipticines [1, 2, and 9-acetoxyellipticine (3)] and protected (peracylated and perbenzylated) glycosyl halides with cadmium carbonate, followed by deprotection. These glycosides were preliminarily evaluated for their antitumor activity in the L1210 leukemia system. Twenty-six (53%) of the 49 glycosides tested were curative, and five [9-hydroxyellipticine L-arabinopyranoside (41b), D-lyxofuranoside (43a), L-lyxopyranoside (44b), D-xylofuranoside (49a), and L-rhamnopyranoside (56)] were selected for extended evaluation on the basis of their high levels of activity. The structure-activity relationships are discussed. The selected glycosides showed remarkable activity in six different murine tumor systems with excellent therapeutic ratios; their efficacy surpassed that of doxorubicin against three of these systems. On the basis of these results and ease of formulation, the two glycosides 41b (SUN4599) and 49a (SUN5073) were selected for further preclinical evaluation and possible clinical development.