Synthesis, determination of the absolute configuration of tonkinelin, and inhibitory action with bovine heart mitochondrial complex I

The first synthesis of two possible diastereomers of tonkinelin was achieved. By comparison of the optical rotation of two candidates of tonkinelin and the natural compound, it is suggested that the absolute configuration of natural tonkinelin is likely to be (17S,18S). The inhibitory activity of these compounds was examined with bovine heart mitochondrial NADH–ubiquinone oxidoreductase. These compounds showed remarkably weak inhibitory activity compared to ordinary acetogenins such as bullatacin.

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