2-Isopropyl-6-methyl-4-hydroxy pyrimidine

Diazinon persisted for about 15 days in a flooded soil (pH 6,6) that had been treated previously with the insecticide but, in a flooded soil that had never been exposed to diazinon, it persisted for about 60 days. Similarly, water from a diazinon-treated rice field inactivated the insecticide within 5 days after incubation. Microorganisms that developed in response to insecticide application accelerated its hydrolysis and the subsequent mineralization of the hydrolysis product, 2-isopropyl-6-methyl-4-hydroxy pyrimidine, to COg. A Fla-vobacterium sp., isolated from water of a treated rice field, had exceptionally high capability to metabolize diazinon as sole carbon source. This provides unequivocal evidence that microbes are involved in the rapid inactivation of diazinon in rice fields. 

Figure 2. Formation of hydrolysis product, 2-isopropyl-6 methyl-4 hydroxy pyrimidine (H) from C-diazinon (D) incubated with water from a rice field treated previously with diazinon (19)...

Soil (diazinon, diazoxon, 2-isopropyl-4-methyl-6-hydroxy-pyrimidine)... 

Extraction of soil with hexane acetone (1 1), centrifugation, separation of hexane from acetone/water layer. Extraction of acetone/water phase with chlorofornrdiethyl ether (1 1), solvent exchanged to methanol. Hexane layer contained diazinon, chloroform/diethyl ether fraction contained 2-isopropyl-4-methyl-6-hydroxy-pyrimidine. 

Dimethyl-4-hydroxy-pyrimidin und Kaliumcarbonat XII/2, 642 4-(Diethoxy-thiophosphoryloxy)-2-isopropyl-6-methyl- E2, 701... 

Plant. Diazinon was rapidly absorbed by and translocated in rice plants. Metabolites identified in both rice plants and a paddy soil were 2-isopropyl-4-methyl-6-hydroxypyri-midine (hydrolysis product), 2-(l -hydroxy-l -methyl)ethyl-4-methyl-6-hydroxypyrimi-dine and other polar compounds (Laanio et al., 1972). Oxidizes in plants to diazoxon (Ralls et al., 1966 Laanio et al., 1972 Wolfe et al., 1976) although 2-isopropyl-4-methyl-6-pyrimidin-6-ol was identified in bean plants (Kansouh and Hopkins, 1968) and as a hydrolysis product in soil (Somasundaram et al., 1991) and water (Suffet et al., 1967). Five days after spraying, pyrimidine ring-labeled C-diazinon was oxidized to oxodiazinon which was then hydrolyzed to 2-isopropyl-4-methylpyrimidin-6-ol which in turn, was further metabolized to carbon dioxide (Ralls et al., 1966). Diazinon was transformed in field-sprayed kale plants to form hydroxy diazinon (9,0-diethyl-0-[2-(2 -hydroxy-2 -pro-pyl)-4-methyl-6-pyrimidii5rl] phosphorothioate which was not previously reported (Par-due et al., 1970). 

Vilsmeier-Haack formylation of 2-(4-methyl-l-piperazinyl)-4//-pyrido-[l,2-n]pyrimidin-4-one with a mixture of POCI3 and DMF at 95°C gave a 3-formyl derivative (93FES1225) while ethyl 4-oxo-6,7,8, 9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-2-acetate at 50 °C yielded a 9-dimethylaminomethylene-3-formyl derivative (01MI4). 3-Formyl-2-hydroxy-8-[2-(4-isopropyl-l,3-thiazol-2-yl)-l-ethenyl]-4//-pyrido[l,2-n]pyri-midin-4-one was obtained from the 3-unsubstituted derivative with oxalyl chloride-DMF reagent in CH2CI2 at room temperature for 3h (OlMIPl). 

Dimethyl-l-(phenyl-acetyl)- E8b, 432 (2,4-Pentandion + Ar — CH2-CO-NH-NH2) Pyrido 4,3-d -l,3-oxazol 6-Methyl-2-phenyl-4,5,6,7-tetrahydro- E8a, Pyrimidine 4-Hydroxy-S-isopropyl-2-phenyl- E9b/2, 100 (R-CH = CH-NR2 + Ar-CO-NCO)... 

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