The Electrochemical Synthesis And Fungicidal Activity Of Compounds With Phosphoryl Moity

Fungicides play an irreplaceable role in agricultural production.Some organophosphates also have fungicidal activities.Traditionally,the synthesis of organic phosphates is mostly involved in the use of transition-metal and environmentally hazardous agents.Organic electrochemical synthesis has the characteristics of high atom economy and environmental friendliness and has attracted much attention in recent years.In this thesis,organic electrochemistry was used to synthesize 3 types of phosphoryl compounds and their antifungal activity of some of the representatives were tested.The detailed research content is as follows:1. A method for the electrochemical construction of phosphoramide and phosphate esters catalyzed by iodine anion was developed.By investigating the effects of electrolytes,electrolyte loading,current density,electrodes and solvents on the reaction,a prototypical reaction was established with triethyl phosphite and morpholine as substrate and potassium iodide as electrolyte.On this basis,different substrates such as phosphite triesters,primary and secondary amines,indole derivatives,alcohols and phenols were extended,and 30 kinds of phosphoramides or phosphates were obtained,with a maximum yield of 95%.The gram-scale reaction proved the scalability of the reaction,and the yields of morpholine and phenol as substrates were 90%and 81%,respectively.Through cyclic voltammetry,hydrogen capture,and control reaction experiments,the mechanism of iodine anion cycle catalysis is proposed.Potassium iodide plays the role of both electrolyte and catalyst in the reaction.This method does not require additional oxidants and transition-metal catalysts,and provides a green and novel method for the synthesis of phosphoramides and phosphates.2. Using trialkyl phosphite and diselenium?tellurium?species,a series of P-Se/Te phosphoryl compounds were obtained.Through the optimization of the reaction,tetra-n-butylammonium bromide was selected as the electrolyte,acetonitrile and water were used as the co-solvent,and the electrolytic reaction was carried out at 50?for 90minutes to realize the synthesis of O,O-diethyl Se-phenyl phosphoroselenoate from triethyl phosphite and diphenyl diselenide.Under optimized conditions,15 kinds of P-Se/Te phosphoryl compounds were synthesized.A mechanism of tetra-n-butylammonium bromide catalysis was proposed through mechanism experiments.This method is green and efficient with a maximum yield of 97%.3. Various available aryl sulfonyl chlorides react with trialkyl phosphites to obtain 17 phosphoryl compounds,with no need of any catalyst.First,the feasibility of p-toluenesulfonyl chloride,p-toluenesulfonyl hydrazide,p-toluenesulfonic acid and p-toluenesulfonamide as sulfur sources were studied,and p-toluenesulfonyl chloride was determined as the sulfur source.Using trialkyl phosphite and arylsulfonyl chloride under constant current and acetonitrile as the solvent,thiophosphate derivatives were synthesized.Both electron withdrawing and donating groups on the aryl ring are suitable for this reaction,and the thiophene ring can also work.Alkyl-substituted phosphites can also be transformed smoothly.72%yield for the gram-scale reaction is reached.Mechanism experiments indicated that the reaction might undergo a free radical procession.4. The antifungal effect of some phosphoryl representatives synthesized in the above chapters was revised.Five types of fungi of Pestalotiopsis theae,Alternaria tenuis Nees,Fusarium graminearum,Rhizoctonia solani Kuhn,and Gloeosporiumtheae-sinesis Miyake were tested.The preliminary screening results showed that the compounds Te1and Te2 had excellent inhibitory effects on the five fungi at 100 mg/L.The rescreening results showed that compound Te1 had an EC₅₀value of 14.11 mg/L and 43.65 mg/L against Fusarium graminearum and Alternaria tenuis Nees,respectively,which were better than the positive control fungicide Thiophanate-Methyl.The EC₅₀values of compound Te2 were 30.14 mg/L,13.70 mg/L,and 40.93 mg/L against Rhizoctonia solani Kuhn,Fusarium graminearum and Alternaria tenuis Nees,respectively,which are better than that of Thiophanate-Methyl positive control.