Synthesis, crystal structure and anti-fungal activity of phenyl-pyrazoline derivatives

Five phenyl-pyrazolines with different substituents were synthesized from 8- (2,6-diethyl-4- methyl phenyl)- 7- oxo- 1,2,4,5- tetrahydro- 7H- pyrazolo [1,2-d] [1,4,5] oxadiazepin-9-yl pivalate. The structures of these compounds were characterized by 1HNMR, 13CNMR, HRMS and X-ray Diffraction. The potential anti-fungal activities have been evaluated against 8 kinds of common fungi at concentrations of 50 ppm and 200 ppm. The result showed that the target compounds exhibit certain anti-fungal activity against the tested fungal strains. Among them, the target compound 3 has a good inhibitory effect on Rhizoctonia solani AG1, which is equivalent to Azoxystrobin, and its EC50 was 86.62 ppm, which indicates that it has the potential to control rice sheath blight. In the future, compound 3 could be used as a pesticide lead compound to control sheath blight of rice, which is worth further study.