Effect of the Newly Synthesized pyrazole, and pyrazolo pyrimidine derivatives on Pythium aphanidermatum (Edson)Fitzp.

Abstract

Root rot caused by Pythium aphanidermatum is one of diseases of olive trees. Three synthetic chemical compounds were tested to assess their inhibitory effect on Pythium aphanidermatum Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), Ethyl 5-amino-7-((3-hydroxy-5-methyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(8) and Ethyl 5-amino-7-((5-amino-2,7-dihydroxypyrazolo[1,5-a]pyrimidin-3-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(9) were synthesis to study their effect on mycelium growth, zoospore and oospore production of P. aphanidermatum isolated from young olive trees cultivated in Ain Seleen, Fayoum governorate, Egypt. Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), showed high efficiency as growth inhibition of fungal mycelia, followed by (pyrazolopyrimidine 9, and then pyrazolopyridine 8 at 10 mg/ L. Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), showed its ability to decline the production of zoo-spores and oospores of the fungus at concentration 300 mg/L, compared to other chemicals of Ethyl 5-amino-7-((5-amino-2,7-dihydroxypyrazolo[1,5-a]pyrimidin-3-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(9), Ethyl 5-amino-7-((3-hydroxy-5-methyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(8). Rate of inhibition in all treatments reached more than 85% in case of the use of Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7). This study offers data for the use of Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7) in controlling fungal disease to olive feeder roots infected by P. aphanidermatum