Alantrypinone and its derivatives: Synthesis and antagonist activity toward insect GABA receptors
作者:Takayuki Watanabe、Mitsuhiro Arisawa、Kenji Narusuye、Mohommad Sayed Alam、Kazumi Yamamoto、Masaaki Mitomi、Yoshihisa Ozoe、Atsushi Nishida
DOI:10.1016/j.bmc.2008.11.017
日期:2009.1
The gamma-aminobutyric acid (GABA) receptor bears important sites of action for insecticides. Alantrypinone is an insecticidal alkaloid that acts as a selective antagonist for housefly (vs rat) GABA receptors, and is considered to be a lead compound for the development of a safer insecticide. In an attempt to obtain compounds with greater activity, a series of racemic alantrypinone derivatives were systematically synthesized using hetero Diels-Alder reactions, and a total of34 compounds were examined for their ability to inhibit the specific binding of [H-3]4'-ethynyl-4-n-propylbicycloorthobenzoate, a high-affinity non-competitive antagonist, to housefly-head membranes. The assay results showed that (1) there is no significant difference between the potencies of natural (+)-alantrypinone and its synthetic racemate; (2) the amide NHs at the 2- and 18-positions are important for high activity; (3) there is a considerable drop in potency for compounds without an aromatic ring at the 16-position; and (4) a large substituent at the 3-position is detrimental to high activity. (c) 2008 Elsevier Ltd. All rights reserved.