Cantharimide and Its Derivatives from the Blister Beetle Mylabris phalerata Palla

Abstract

Eleven new monoterpenoids including three 1-methyl cantharimide-type derivatives (1-3), five 1,2-dimethyl cantharimide-type derivatives (4, 5, 7-9), and three 1-hydroxymethyl-2-methyl cantharimide-type derivatives (10-12), together with seven known cantharimides (6, 13-18), were isolated from Mylabis phalerata Palla. The planar structures and absolute configurations of compounds 1-14 were fully elucidated on the basis of spectroscopic analysis, ECD spectra, single-crystal X-ray diffraction analysis, and chemical methods. Compounds 6, 15, 16, and 18 were found to be potent inhibitors of HBV virus, with IC50 values of 62, 42, 58, and 19 μM.

Remote, Late-Stage Oxidation of Aliphatic C–H Bonds in Amide-Containing Molecules

“…Palasoninimide B, bearing an interesting cantharimide core, is a natural product recently isolated from Mylabis phalerata Palla and found to be a potent inhibitor of hepatitis B virus (HBV). 22 The Fe(CF 3 PDP) 2 oxidation of the nosylated palasoninimide B analogue 32 resulted in remote oxidation product 34 in 64% yield and 6:1 selectivity with the cyclic ether cantharimide substructure untouched (Scheme 3A). For N -methyl derivative 33, the higher nucleophilicity of the amide nitrogen versus that of the imide led it to preferentially reacting with the alkylating reagent to form a stable imidate salt.…”

The Solid-State Structures of Cyclic NH Carboximides

“…Twenty structures exhibit a linear ribbon type of hydrogen bonding (C(4)) in pattern B. These are compounds 133 [122], 134 [124], 135 [120], 136 [125], 137 [126], 138 [126], 139 [127], 140 [128], 130 [121], 141 [129], 142 [124], 143 [130,131], 144 [132], 145 [132], 146 [119], 147 [119], 148 [113], 149 [133] and 150 [134] (Figure 45).…”

“…128 [119], 129 [120], 130 [121], 131 [122] and 132 [123] (Figure 44) exist as simple R Twenty structures exhibit a linear ribbon type of hydrogen bonding (C(4)) in pattern B. These are compounds 133 [122], 134 [124], 135 [120], 136 [125], 137 [126], 138 [126], 139 [127], 140 [128], 130 [121], 141 [129], 142 [124], 143 [130,131], 144 [132], 145 [132], 146 [119], 147 [119], 148 [113], 149 [133] and 150 [134] (Figure 45). One structure, compound 151 [135] (Figure 46) exhibits the square hydrogen bonding R 4 4 (16) pattern G involving four molecules.…”

Recent Advances in Herbal Medicines for Digestive System Malignancies

“…Mylabris has been used in cancer treatment for more than 2000 years (Lao et al, 2013 ; Zeng et al, 2016 ). Cantharidin (CTD) (Supplementary Figure 1 ), a terpenoid, is the main active ingredient of Mylabris, and it has a significantly cytotoxic effect on tumor cells (Kadioglu et al, 2014 ; Hsia et al, 2016 ).…”