Synthesis and Fungitoxicity of 2-Oxo/Thiopyrimidine Derivatives

Ten derivatives of pyrimidin-2-one, four derivatives of pyrimidin-2-thione and six phenyl hydrazone derivatives of pyrimidin-2-one were synthesised. These compounds exhibited fungitoxicity to the mycelial growth of Rhizoctonia bataticola ana Sclerotium rolfsii. 1 -H-5, 6-dihydro-6-(4-N,N-dimethylaminophenyl)-4-pheny 1-2-oxopyrimidine (EC₅₀ = 98 mg/L) was found to be the most active compound against R. bataticola, while 1-H-5,6-dihydro-2-oxo-6-phenylpyrimidine (EC₅₀ = 292 mg/L) exhibited promising activity against S. rolfsii. Structure activity relationships of these compounds are discussed.