Synthesis and bioactivity of O-ethyl phosphorodiamidates derived from quinazolin-4-ones and either amino acid esters or fatty amines

Synthesis of several O-ethyl phosphorodiamidates derived from unsubstituted : or 6- bromo-, or 6-nitro-3-amino-2-methyl-3H-quinazolin-4-one and either amino acid esters or fatty? amines is described. These compounds showed hig h insecticidal activity to ward mosquito larvae, With lethal concentrations LC,, and LC,, as low as 0.028 and 1.724 ppm,, respectively. The highest ac tivity was observed with those compounds containing both a nitro substituen t and a IO-carbon-atom fatty-amine moiety. Multiple regression analysis was used to explain the larvicidal activity variation of these compounds. The larvicidal activity generally decreased according to the following order of amino acid moieties: glutamic acid > methionine > glycine > alanine > phen ylalanine. (C) 1999 John Wiley & Sons, Inc.