Synthesis And Bioactivity Of2,3-Diaryl-3,4-Dihydro-Naphth[1,3] Oxazines

Heterocyclic compounds become one of the hot point in the research and development ofnew pesticides discovery due to their broad biological activity.1,3-Naphthoxazines aresix-membered heterocyclic compounds containing nitrogen and oxygen hetero atom possesswide range of broad biological activity such as, anti-cancer, anti-tumo, analgesic andinsecticidal and fungicidal activity. They will have broad prospects in the field of drugdiscovery.In this thesis, novel2,3-diaryl-3,4-dihydro-1,3-nanphthoxazines were designed and thesynthesis was studied. The fungicidal activity of the prepared compounds were alsopreliminarily investigated.15Novel2,3-diaryl-3,4-dihydro-1,3-nanphthoxazines weresynthesized by reduction of the Schiff bases with NaBH4giving the corresponding1-(arylaminomethyl)-2-naphthols, followed by reaction with aromatic aldehydes. Thestructures of the target compounds were characterized with IR,1H NMR,13C NMR.(1) The intermediate1-(arylaminomethyl)-2-naphthols36a~36f were prepared75.2%~91.1%by one-pot reaction of2-hydroxy-1-naphthaldehyde with substituted anilinevia Schiff bases, which was directly reduced by NaBH4without purification. It was found thatelectron-releasing group on the benzen ring of the aniline gave much higher yield than thosewith electron-withdrawing group.(2)2,3-Diaryl-1,3-nanphthoxazines33a~33o were prepared by reactions of1-(arylaminomethyl)-2-naphthols with substituted aromatic aldehydes. It was studied theeffects of the loading of TMSCl, reaction time, reaction temperature and reactants ratio onyield of the reaction. The optimation conditions were obtained: reaction temperature80℃,reaction time5h, the amount of catalyst TMSCl15mol%, the ratio of1-(arylaminomethyl)-2-naphthol to aldehyde1.1:1. Under this condition, the title compounds2,3-diaryl-1,3-nanphthoxazines33a~33o were synthesized. The results showed compoundswith electron-donating group on the benzen ring connecting with nitrogen atom weregenerated in higher yields than those with electron-withdrawing group. Moreover, the locationof the nitro group on the benzen ring at2-position of the oxazine ring has good relationshipwith the yield: para> ortho> meta.(3) The fungicidal activity of15target compounds2,3-diaryl-1,3-nanphthoxazines33a~33o were tested, and the results showed that the tested compounds exhibited the highestactivity against magnaporthe grisea, the inhibition activity of compound33b is78.3%,73.9%for compound33l. Secondly, compound33a showed76.5%inhibition activity against gibberella zeae,73.5%for compound33h. The inhibition activity of compound33a againstphytophthora capsici is76.9%, and65.4%for compound33h. Compound33m showed63.6%inhibition activity against sclerotinia sclerotiorum.