Synthesis And Biological Activities Of Uracil Derivatives Containing Thiadiazole Or Pyrimidine

"High-efficiency, low toxicity, safety" has already become the theme of discovering new pesticides. Protoporphyrinogen oxidase (Protox) inhibitors is a kind of highly active and tag type herbicide, it make action on a catalytic synthesis of chlorophyll of enzymes in the plant cell, which ensure the toxic selectivity between animals and plants. They have the characteristic of high efficiency, short residual time, high selectivity and safty to non-target creature and friendly to environment. Therefore, it developed so fast in recent years and has become one of the most prosperous areas in the research of the pesticide chemistry.Among them, Uracil derivatives of Protoporphyrinogen oxidase (Protox) inhibitors get more and more attention of people because of its excellent herbicidal activity in recent years. As a result, it becomes one of the hot spot of the development of new pesticides. In order to search high activity Uracil derivatives of Protoporphyrinogen oxidase (Protox) inhibitors, the moiety of 4,6-dimethoxypyrimidine and 1,3,4-thiadiazole that have good biological activity were brought to the Uracil pyrimidine framework according to the principle of combination of bioactive substructure. Two series of the new Uracil pyrimidine derivatives containing amide moiety were designed and synthesized. The structure of these compounds are listed as follows:1) containing the moiety of 4,6-dimethoxypyrimidine of the Uracil pyrimidine derivatives Ⅰ-12a-Ⅰ-121 (12 compounds) Ⅰ-12a (R1= R2= H, R3= 2-Y); Ⅰ-12b (R1= F, R2= H, R3= 2-Y); Ⅰ-12c (R1= H, R2= F, R3= 2-Y); Ⅰ-12d (R1= R2= H, R3= 3-Y); Ⅰ-12e (R1= F, R2= H, R3= 3-Y); Ⅰ-12f (R1= F, R2= H, R3= 3-Y); Ⅰ-12g (R1= R2= H, R3= 4-Y); Ⅰ-12h (R1= F, R2= H, R3= 4-Y); Ⅰ-12i (R1= H, R2= F, R3= 4-Y); Ⅰ-12j (R3= 2-Y); Ⅰ-12k (R3= 3-Y); Ⅰ-121 (R3= 4-Y).2) containing the moiety of 1,3,4-thiadiazole of the Uracil pyrimidine derivatives Ⅱ-9a-Ⅱ-9n (14 compounds) (?) Ⅱ-9a(R1=R2=H)；Ⅱ-9b(R1=F,R2=H)；Ⅱ-9c(R1=H,R2=CH3)；Ⅱ-9d(R1=F,R2=CH3)； Ⅱ-9e(R1=H,R2=Et)；Ⅱ-9f(R1=F,R2=Et);Ⅱ-9g(R1=H,R2=i-Pr)；Ⅱ-9h(R1=F,R2=i-Pr)； II-9i(R1=H,R2=n-Pr)；Ⅱ-9j(R1=F,R2=n-Pr)；Ⅱ-9k(R1=H,R2=n-Bu)；Ⅱ-9l(R1=F,R2=n-Bu)； Ⅱ-9m(R1=H,R2=Ph)；Ⅱ-9n(R1=F,R2=Ph).The structures of all target compounds have been confirmed by 1H NMR and elemental analysis,some of them were als characterized by MS and IR spectroscopy, their spectral properties,synthetic methods,reaction conditions were also studied.In addition,the preliminary biological activities of the target compounds were evaluated. The results shows that some compounds displayed good herbicidal activity,and their structures and herbicidal activity relationships were also investigated.