Synthesis And Structure Of Pyrazolo [4, 3-d] Pyrimidin-7(6H)-one Derivatives

Pyrazole derivatives, one of the focuses in the research and development of agrochemicals, has been found to show widespread biological activities. Many of them have been used as fungicide, pesticide, acaricide, herbicide and medicine. In this paper, we designed and synthesized three series of new compounds from the readily available starting compound 4-substituted aniline and malonitrile in six straightforward steps with high yields (65%-97%). The structures of the target compounds (â… _Aa-Ax,â… _Ba-Bq,â…¡_a-nandâ…¢_a-d) have been confirmed by IR, ¹HNMR,GC/MS and elemental analysis. Furthermore, some of them (â… _Ac,â… _Ae,â… _Aj,â… _Au andâ… _Bh) were determined by X-ray crystallography.According to their structures, these compounds can be divided into three series as follows:(1)6-aryl-3-carbonitrile-5-alkyl/dialkylamino-1-p-tolyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-oneâ… :(2)6-aryl-3-carbonitrile-5-aryloxy-1-p-tolyl-6, 7-dihydro-1H-pyrazolo [4,3-d]pyrimidin-7 (6H)-oneâ…¡:(3) 6-aryl-3-carbonitrile-5-alkyloxy-1-p-tolyl-6,7-dihydro-1H-pyrazolo[4,3-d] pyrimidin-7(6H)-oneâ…¢:...