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BACKGROUND: The development of environmentally friendly and novel structural pesticides is now an area of intense research in the agriculture field. Spirocyclic tetronic acids such as spiromesifen are typical compounds of this kind. In order to discover novel compounds with improved and broader-spectrum insecticidal activities, a series of spiromesifen derivatives were synthesised and bioassayed. RESULTS: The derivatives were identified by 1H NMR and MS. Preliminary bioassays demonstrated that some bioactivities of compounds 5a to 5u were better and had a broader spectrum than the lead compound spiromesifen. Moreover, these compounds showed better insecticidal activities against Mythimna sepatara and Aphis fabae than acaricidal activities against Tetranychus cinnabari. Furthermore, LC50 of 5s against Aphis fabae reached 1.09 mg L−1. At the same time, compounds 5g, 5i, 5k and 5r also warrant further study because of their superior bioactivities to spiromesifen. What is more, suitable carbon chain length in the 4-position ester and the log P value of these spiromesifen derivatives dramatically influenced their insecticidal activities. Butyric or pentanoic ester and a log P value of 4.0-6.0 may be preferred. CONCLUSION: The present work demonstrates that some spiromesifen derivatives can be used as potential lead compounds for developing novel insecticides and acaricides. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In the title compound, C(24)H(24)O(4), a derivative of the potent insecticide and miticide spiro-mesifen, one cyclo-pentane C atom is disordered over two positions with occupancies of 0.574 (12) and 0.426 (12), resulting in respective envelope and twisted conformations for the cyclo-pentane ring. The atom at the flap position is 0.620 (5) Å out of the mean plane formed by the other four atoms of the envelope form. The furan ring makes dihedral angles of 68.26 (3) and 69.38 (2)°, respectively, with the 2,4,6-trimethyl-phenyl and benzene rings. The dihedral angle between the two benzene rings is 62.27 (3)°.

The title compound, C(24)H(23)ClO(4), is a potent insecticide and miticide. The five-membered cyclo-pentane ring displays an envelope conformation with the atom at the flap position 0.611 (2) Å out of the mean plane formed by the other four atoms. The furan ring makes dihedral angles of 71.3 (2) and 81.9 (2)°, respectively, with the 2,4,6-trimethyl-phenyl and 4-chloro-phenyl rings. The dihedral angle between the two benzene rings is 76.6 (1)°. In the crystal, mol-ecules are linked through weak inter-molecular C-H⋯O hydrogen bonds, forming chains running along the c axis.