Carbon-14 radiolabeling and tissue distribution evaluation of MMV390048.

The antimalarial compound MMV390048 ([14 C]-11) was labeled with carbon-14 isotope via a 3-step synthesis. It was obtained in a 15.5% radiochemical overall yield from carbon-14 labeled methyl iodide with a radiochemical purity of >99%. After single oral administration of [14 C]-11 to albino and pigmented rats its tissue distribution profile was studied. Tissue distribution results showed high local exposure in the GI tract and excretory organs but low exposure of all other tissues. The radioactivity uptake was higher in the eyes of the pigmented rats than in the eyes of the albino rats at all-time points. The highest accumulation reached in the eyes of the pigmented rats was 0.46% at 6 hours. However, these levels are still very low as compared to the other organs studied. There was very little radioactivity from MMV390048 ([14 C]-11) present in the skin of both the albino and pigmented rats. The results obtained are supportive of further development of MMV390048 as a potential antimalarial compound.

(Z)-Ethyl 2-hy-droxy-4-oxo-4-(1,4,5,6,8-penta-meth-oxy-naphthalen-2-yl)but-2-enoate.

The title compound, C21H24O9, crystallizes with two independent mol-ecules in the asymmetric unit which are almost centrosymmetrically related to each other. The ethano-ate group in one of the two mol-ecules is disordered over two positions with a site-occupation factor of 0.880 (7) for the major occupied site. In the crystal, the 1,3-diketone group exists in the keto-enol isomeric form due to the stabilizing effect of the intra-molecular O-H⋯O hydrogen bond present in this form. The compound packs as a layered structure in which C-H⋯π and C-H⋯O inter-actions are present within and between the layers.

The synthesis of the pyranonaphthoquinones dehydroherbarin and anhydrofusarubin using Wacker oxidation methodology as a key step and other unexpected oxidation reactions with ceric ammonium nitrate and salcomine.

The synthesis of two closely related pyranonaphthoquinones, dehydroherbarin and anhydrofusarubin, is described. The construction of the naphthalene nuclei was achieved using the Stobbe condensation reaction using 2,4-dimethoxybenzaldehyde and 2,4,5-trimethoxybenzaldehyde as their respective starting materials. Two key steps en route include a PIFA-mediated addition of a methoxy substituent onto the naphthalene skeleton and a Wacker oxidation reaction to construct the benzo[g]isochromene nucleus. Two interesting oxidation reactions of the intermediate isochromene enol ether of 7,9-dimethoxy-3-methyl-1H-benzo[g]isochromene-5-ol were observed. Treatment of the substrate with salcomine resulted in the formation of (3-formyl-4-hydroxy-6,8-dimethoxynaphthalene-2-yl)methyl acetate, while treatment of the same substrate with CAN resulted in the formation of racemic (3R,4R)-3-hydroxy-7,9-dimethoxy-3-methyl-5,10-dioxo-3,4,5,10-tetrahydro-1H-benzo[g]isochromen-4-yl nitrate.