| In recent years,along with the enhancing awareness of environmental protection and concept of green chemistry,research and development of pesticide with low toxicity and high efficiency has become an important research topic due to the high toxic organic phosphorus pesticides which are gradually replaced by a number of novel pesticide varieties containing heterocyclic structures and sulfone structures with high efficiency,low toxicity and low residue.It is very attractive to synthesize new pesticides with two or more functional groups combining organophosphorus structures,heterocyclic structures or sulfone structures.Based on the application of organophosphorus compounds in the field of organic synthesis,and combining the concept of combinatorial chemistry and green chemistry,this paper investigates a large number of literatures and develops a series of novel functional organophosphorus compounds with antifungal activity test.Rigorous experiments are carried out and detail data are obtained with theoretical research as the basis,experimental operation as the means,data analysis as the medium,product representation as the evidence,and mechanism study as the core.The details are summarized as follows:1.Photocatalysis synthesis of phosphine oxide derivatives containing thiazole groupsPhotocatalysis involving single electron transfer routes has been widely concerned and successfully applied in organic synthesis due to its sustainability and the characteristics of green chemistry.A series of phosphine oxide derivatives containing thiazole structure were prepared with diarylphosphine oxides and thiazole compounds.The photocatalyzed coupling reaction with organic dye as sensitizer was performed without metal,oxidant,or additive.The reaction is not only the first photocatalytic C(sp2)-P cross-coupling reaction,but also a hydrogen evolution reaction.Then the optimum reaction conditions were screened out with solvents,photosensitizers and gas atmospheres investigated.Various substituted phosphine oxides and thiazole compounds are used to test the substrate scope.The compounds were isolated and characterized by 1H-NMR,13C-NMR,31P-NMR,HR-MS,IR,m.p.,among which 13 compounds were new and have not been reported before.The mechanism of reaction was explored by deuterium experiment,hydrogen detection experiment and free radical capture experiment.A plausible mechanism was put forward,and the law of reaction was summarized.2.Autoxidative cross-coupling synthesis of phosphine oxide derivatives containing heterocyclic groupsOxygen has been widely used as oxidant in oxidative coupling by chemists due to its advantages of cheap,efficient,stable,green,sustainable and so on.In particular,the autoxidative cross-coupling of general compounds in autoxidative coupling are numbered in except for the autoxidative coupling of active compounds.A series of phosphine oxides containing thiazole structure and quinoxaline structure were prepared with diarylphosphine oxide and thiazole,quinoxaline compounds,exhibiting the first autoxidative C(sp2)-P cross-coupling reaction.Water is the only by-product of the reaction which accords with the concept of green and atom economy.Then the optimum reaction conditions were screened out with solvents,catalysts and temperature investigated.Various substituted phosphine oxides and thiazole,quinoxaline compounds are used to test the substrate scope.The compounds were isolated and characterized by 1H-NMR,13C-NMR,31P-NMR,HR-MS,IR,m.p.,among which 14 compounds were new and have not been reported before.The mechanism of reaction was explored by deuterium experiment,oxygen free radical validation experiment,free radical capture experiment,and efficiency comparison experiment.A plausible mechanism was put forward,and the law of reaction was summarized.3.Acid-mediated the synthesis of phosphine oxide derivatives containing azirines groups2H-Azirines,the smallest unsaturated nitrogen heterocycles in nature,can be used as a high-active reagent for the synthesis of amides and multiple nitrogen heterocyclics due to its unique structure containing a three-membered ring in organic synthesis.A series of phosphine oxide derivatives containing azirines groups were prepared with allenylphosphine oxides and sodium azide via an elimination-rearrangement-cyclization reaction in the promotion of acetic acid.These bifunctional vinyl compounds which containing both an azirine structure and an organophosphorus structure are reported for the first time.Then the optimum reaction conditions including solvents,acids and temperature were screened out.Various substituted allenylphosphine oxides were used to test the substrate scope.All of compounds isolated were new and characterized by 1H-NMR,13C-NMR,31P-NMR,HR-MS.The plausible mechanism was proposed by related literature research,and the law of reaction was summarized.4.Acid-mediated the synthesis of phosphine oxide derivatives containing sulfone groupsThe synthesis methods of vinyl sulfones have been developed and innovated by scientists due to the widely application of the unique chemical structure in natural products and pesticides along with the concept of green chemistry.A series of phosphine oxide derivatives containing sulfone groups were prepared with allenylphosphine oxides and sulfonates in the promotion of acetic acid.These bifunctional 1,3-butadiene and allene compounds containing both a sulfone structure and an organophosphorus structure are reported for the first time.Then the optimum reaction conditions were screened out with solvents,acids and temperature investigated.Various substituted allenylphosphine oxides and sulfonates are used to test the substrate scope.All of the compounds which have not been reported before were characterized by 1H-NMR,13C-NMR,31P-NMR,HR-MS,IR,m.p.,X-ray.The mechanism of reaction was explored by the control experiment.A plausible mechanism was put forward,and the law of reaction was summarized.5.Antifungal activity determinationTo test antifungal activity of some organic phosphorus compounds which have never been reported in literatures,the inhibitory rate of 91 compounds to Botrytis cinerea,Altemaria solani,Gibberella zeae,Rhizoctonia solani and Alternariamali were determined by growth rate method;the toxicity of some compounds to Botrytis cinerea,Rhizoctonia solani and Alternariamali were also determined;the structure-activity relationship was discussed based on the antifungal activity of the target compounds.The results showed that most of the 91 compounds had different degrees of activity to the tested fungi.The toxicity of some compounds to the tested fungi was determined,the EC50 of the compounds A2.A3 and A7 to Alternariamali were 25.2 ?g/mL,22.3 ?g/mL,24.1 ?g/mL;the EC50 of the compound A2 to Rhizoctonia solani was 10.8 ?g/mL;the EC50 of the compounds A1?A3?A11?A16?A20?A21 and B8 to Alternariamali were 93.8 pg/mL,143.2 ?g/mL,167.2 ?g/mL,64.4 ?g/mL,95.0 ?g/mL,90.3 ?g/mL,83.8 ?g/mL,which means the activity is worse than the control agent,but also showed better activity.In summary,four new methods are reported in this paper for the synthesis of phosphine oxide derivatives.With only organic small molecular dyes,small molecules oxygen,acetic acid as catalysts or accelerators for the reaction instead of transition metal catalyst,and hydrogen,water,recyclable phenol as the by-products,the reactions accord well with the concept of green chemistry and green pesticide due to the good atomic economy and green environmental protection.The compounds used in the activity test showed a certain activity,which could provide a new direction for the creation of new pesticides. |
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