Studies On Synthesis And Properties Of Novel Biological Activity Pyrazole And Pyrazolopyrimidine Derivatives

Pyrazole and pyrazolopyrimidine derivatives, one of the focuses in the research and development of agrochemicals, have been found to show widespread biological activities. Many of them have been used as pesticide, fungicide, herbicide and medicine. In this paper, we studied the synthesis of novel pyrazolopyrimidines by utilizing a tandem aza-Wittig and annulation reaction and pyrazole derivatives. Their biological activities were also researched and many of them showed good herbicidal or fungicidal activities. It may be summarized as follows:One hundred and seventy two unreported pyrazolopyrimidine and pyrazole derivatives in eight series were synthesized. The structure of all these compounds were confirmed by 1H NMR, IR, MS, elemental analyses and X-ray diffraction. Those compounds are summarized as follow:I -5and I -6 : 2-(2,4-dichlorophenoxy)-(5-alkylamino-3,4-sustited-pyrazol)-l-yl-ethanone (16)II-5: 2-(2,4-dichlorophenoxy)- pyrazol-5- amino ethanone (4) .III-5: 6-alkylamino- 3-alkylthio-1,5-diphenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (33).IV-5: 6-arylamino-3-alkylthio-1 -phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (12).V-5: 5-amino-3-alkylthio-l-phenyl-6-arylamino-lH-pyrazolot3,4-d]pyrimidin-4(5H)-one(24).VI-5: 6-arylamino-3-alkylthio-1 -phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-amine (17).VII-4(5): 6-alkoxyl(aroxyl)-3-alkylthio-lH-pyrazolo[3,4-d]pyrimidin-4(5H)-one (24) .VIII -5 : 2-[4-(3-methylthio-l-phenyl-4(5H)-lH-pyrazolo[3,4-d]pyrimidin-6-yloxy)-phenoxyl]carboxylic acid ester (32).The reaction 5-amino-lH-pyrazole with 2,4-dichlorophenoxy acetyl chloride was studied. Novel facile synyhetic methods for 6-alkylamino-3-alkylthio-l,5-diphenyl-lH-pyrazoIo[3,4-d]pyrirnidin -4-(5H)-ones ( III -5), 5-amino-3-alkylthio-l-phenyl-6-arlyamino-lH-pyrazolo[3,4-d]pyrimidin-4 -(5H)-ones (V-5), 6-alkyoxyi (aryoxyl)-3-alkylthio-l,5-diphenyl-lH-pyrazolo[3,4-d]pyrimidin-4-(5h)-ones ( VII -4(5)) and 2-[4-(5-aryoxyl-3-methylthio-l-phenyl-4(5H)-oxo-lH-pyrazolo[3,4-d]-pyrimidin-6-yloxyl)-phenoxyl]-carboxylate (VI-5) were proposed, which included a tandem aza-Wittig and annulation reaction and gave good yields and high regioselectivity in the mild condition.And the reaction of 4-ethoxylcarbonyl (or cyano) -pyrazole-5-yl-carbodiimide with various neucleophiles was investigated also. The selectivity of cyclization of the carbodiimide with NH3, RNH2 and RNHNH2 were studied. Some of gualidene-type intermediates were isolated and the possible mechanism was suggested.In addition, the reactions of the carbodiimide with alkanol and substituted phenol were studied firstly. When the nucleophile was alkanol, the reaction proceeded smoothly in the room temperature to give 6- alkoxyl pyrazolo[3,4-d]pyrimidin-4(5H)-ones. When the nucleophile was substituted phenol, the reaction took place in presence of solid potassium carbonate, while the reaction undergone in lower yields or did not proceed if substituted phenol hold electron-drawing group.Finally, the prediminary bioassays of the new compounds mentioned were measured. The results showed that the compounds of I -5(6), II -5, VII-4(5)and VIII-5 possessed excellent herbicidal activity and the compounds of III-5,IV-5,V-5 and VI-5 showed good fungicidal activity. For example, at the dosage of 10 mg/L compounds I and II showed more than 90% inhibitory rate to the root of rape and compounds II showed more than 91% to the stalk of rape. Some new precursor compounds possessed high biological activities have been found. And the relationship of the biological activity and their structures were studied also.