.5 - Fluoro-phenyl -2 - Furancarboxylato Derivatives Synthesis And Herbicidal Activity Determination

More researches have shown 5-aryl-2-furoic acid derivatives exhibit plant protection properties like plant growth regulators, fungicidal and herbicidal activities. Taking advantage of some fluorine decorated herbicides, utilizing active-factor- addition method and with the assistance of phase transfer catalysis, we have mainly accomplished two tasks in this paper in search of lead compounds for new herbicide. (1) Fifteen new Series (Ⅰ) compounds, N'-(4,6-disubstitutedpyrimidin-2-yl)-N-(5-fl- uorosubstitutedphenyl-2-furoyl)thioureas were synthesized from 5-fluorosubstituted- phenyl-2-furoic acids through three steps. (2) On the basis of Series (Ⅰ) compounds, another fifteen new Series (Ⅱ) compounds, 5,7-disubstituted-2-(5-fluorosubstituted- phenyl-2-furoylimino)-2H-1,2,4-thiazolo[2,3-a]pyrimidines were prepared by oxidizing cyclization of Series (Ⅰ) using bromine as oxidant.The thirty fluorine decorated compounds of Series (Ⅰ) and Series (Ⅱ) are all new compounds and their structures were confirmed by elementary analysis, 1H NMR, MS and IR. Their physical, chemical and spectral properties, reaction conditions and synthetic methods were discussed as well. The structural formulae of Series (Ⅰ) and (Ⅱ) are as follows:To further investigate the relationship between the structure of target compound and its properties, we obtain one related crystal structure by single crystal X-Ray diffraction analysis, and have some preliminary discussion on its structure and activities.Shanghai Branch of National Pesticide R&D South Center helped to do the preliminary screening of biological activities. Also, Bayer CropScience AG helped to do the Vivo Ultra High Throughput Screening in Germany. The results indicated that some of the fluorine decorated compounds of Series (Ⅰ) and Series (Ⅱ) have both good and selective herbicidal activities. And some Series (Ⅰ) compounds showed better fungicidal activities towards Pyricularia orizae and Phytophthora infestans.