Biomedical subjects
Publications and source records attributed to Han-Hong Xu.
This paper describes the syntheses and biological activities of a number of spiroketal enol ethers which are analogues of the plant extract tonghaosu. The insecticidal potential of this spiroketal system is assessed.
Tonghaosu (1), a lead for a botanical antifeedant, and its 22 analogues were synthesized according to a previously reported concise and straightforward procedure. The structures of all new compounds were confirmed by NMR, IR, MS, and HREIMS or elemental analysis. Their insect antifeedant activities against the large white butterfly (Pieris brassicae L.) were examined, and six analogues (Z- and E-6h and Z-isomers of 6i-l), which contain 1,3-diyn or 3,4-methylenedioxyphenyl acetylene group, showed considerable antifeedant activity. Interestingly, Z-isomers of 6i-k are much more active than their corresponding E-isomers.
The structure determination of the title compound, rotenone alpha-oxime [systematic name: 1,2,12,12a-tetrahydro-8,9-dimethoxy-2-(1-methylethenyl)-[1]benzopyrano[3,4-b]furo[2,3-h][1]benzopyran-6(6H)-one oxime], C(23)H(23)NO(6), confirms that the molecule has an approximately V-shaped structure. One of the rings has a typical cyclohexene-like monoplanar conformation and the central ring adopts a 1,2-diplanar conformation.