Synthesis and anti-TMV activity of novel N-(3-alkyl-1H-pyrazol-4-yl)-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides

In order to investigate the biological activity of novel bis-pyrazole compounds,a series of N-（3-alkyl-5-（N-methylcarbamyl）- 1H-pyrazol-4-yl）-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides were designed and synthesized with ethyl 3-alkyl-1H-pyrazole -5-carboxylate 1 as starting materials.N-Methyl-3-alkyl-4-amino-1H-pyrazole-5-carboxamides 6 were obtained from 1 via 5 steps.3-Alkyl-4-substitued-1H-pyrazole-5-carboxyl chlorides 4a,4b,11a,11b,11c or 12 were also obtained from 1 via several steps.Target compounds 7a-7g were obtained after the reaction of 6 with the above 1H-pyrazole-5-carboxyl chlorides.Preliminary bioassay showed some compounds possessing good inactivation effect against TMV（tobacco mosaic virus）.Compound 7a showed higher activity superior to ningnanmycin at a concentration of 5.0×10^-4 g/mL and equal activity at 1.0×10^-4 g/mL;7b and 7c showed equal activity to virazole both at concentrations of 5.0×10^-4 g/mL and 1.0×10^-4 g/mL.