Synthesis And Acaricidal Activity Of Chalcone Derivatives

Chalcone is a class of compounds which have 1,3-diphenyl-propenone skeleton(C6-C3-C6)as skeleton structure.Natural chalcones are widely distributed in the plant kingdom.Many of them have illustrious pharmacological activities,such as anti-bacterial,anti-inflammatory,anti-malarial,anti-tumor,anti-viral,and anti-cardiovascular.There are lots of research on chalcone,while most researchers concentrate on modifications aromatic ring chalcones or heterocyclic chalcones.Currently,the study on the chain connecting two benzene rings are rarely reported.Using chalcone which has acaricidal activity as basic structure,we designed and synthesized a class of chalcone derivatives with different chain lengths.After assaying their acarcidal activity against Psoroptes cuniculi,we discussed the structure-activity relationship preliminarily.Based on the results,the benzene ring modifications of the high activity compounds were designed and synthesized to see the effect of the substituents on acarcidal activity.The details and the most important results of the thesis are listed below:1.Using acetophenone or aryl ethanone and benzaldehyde as raw material,we synthesized 4 chalcone derivatives via Claisen-Schmidt reaction.Using ?-bromoacetophenone or ?-bromoarylethanone and phenyl substituted aliphatic aldehyde as the raw material,we synthesized 15 compounds contain B-E four kinds chalcone derivatives.We also got a reduction product C-7.Each compound was characterised by 1H NMR,13 C NMR and ESI-MS,respectively.2.Acaricidal activity in vitro against Psoroptes cuniculi of the chalcones was assayed by dipping mite method.The the preliminary screening result of acaricidal assay showed that over 90% compounds show 50%-100% acaricidal mortality at 1.0 mg/mL.There were 7 compounds(A,A-2,A-3,B-5,C-3,C-4,C-6)whose activity were close to the frontline clinical acaricidal drugs-ivermectin at 0.5 mg/mL.3.The preliminary structure-activity relationship of chalcone and its derivatives on their acaricidal activity was discussed.Substituting with an electron donating group at the 4-site on the A ring of chalcone would reduce its activity,while substituting with an electron withdrawing group had little effect.Acaricidal activity of compounds decreased from A to E.The more methylene introduced,the weaker would the activity be.Carbonyl is the essential structure for acaricidal activity,there would be no activity without carbonyl.The effect of the substituent at A ring on activity depending on the species and the position for B compounds and C compounds.