Synthesis and Bioactivity of O-Ethyl Phosphorodiamidates Derived from Quinazolin-4-ones and Either Amino Acid Esters or FattyAmines.-The synthesis of several O-ethyl phosphorodiamidates derived from quinazolinones (II) and either fatty amines [→(V), 8 examples] or amino acid esters [→(VII), 9 examples] is described. The compounds show high insecticidal activity towards mosquito larvae. The highest activity is observed for compound (Vd) bearing both a nitro-substituent and a fatty amine moiety. Structure-activity relationships are discussed. -(ALI, HUSSEIN M.; MOSTAFA, AZZA A.; EL-ZOHRY, MAHER F.; Heteroat. Chem. 10 (1999) 6, 455-460; Dep. Agric. Biochem., Ain-Shams Univ., Cairo 11241, Egypt; EN)