The Synthesis And Biological Activity Of Benzofuranol Derivatives Containing Thiazol, Imine And Hydrazone Structures

Benzofuran derivatives exhibit insecticidal, fungicidal, antineoplastic, immuno-suppressive agents and other biological activities. It is an important research direction forbenzofuran derivatives to associate benzofuran ring with other effective groups to obtainhighly active compounds. Thiazole heterocyclic compounds possess a broad spectrum ofbiological activities with high efficacy and excellent absorption, such as insecticidal,fungicidal, herbicidal, etc. Due to their special bioactivities and playing an essential role inorientation and complex formation, schiff base and hydrazone compounds have wideapplications in antioxidant, antitumor, antibacterial, insecticidal and other areas. In order tosearch for novel compounds with higher activity, we designed and synthesized a series of newcompounds containing the benzofuran ring, thiazole ring, schiff base and hydrazone structuresby following the principle of Substructure Link Way.Twenty-five (E)-N-benzylidene-4-(7-alkoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl)thiazole-2-amines were designed and synthesized from1-(7-alkoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl)alkyl ketones by α-bromation, cyclization with thiourea, finally, antacidedwith ammonia to give4-(7-alkoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl)thiazole-2-amino, and then imidization with aromatic aldehyde. The structures of newly compoundswere clearly characterized by1H NMR, MS spectra and elemental analysis.Forteen (E)-2-(2-benzylidenehydrazinyl)-4-(7-methoxy-2,2-dimethyl-2,3-dihydrobenzo-furan-5-yl)thiazoles were designed and synthesized from the substituted benzaldehyde as rawmaterials, by condensation with thiosemicarbazide, and cyclization with2-bromo-1-(7-methoxy-2,2-dimethyl-2,3-dihydrobenzofuran-5-yl) ethanone to give the novel hydrazonederivatives. Their structures were established by1H NMR.Firstly, the samples of (E)-N-benzylidene-4-(7-alkoxy-2,2-dimethyl-2,3-dihydrobenzo-furan-5-yl)thiazole-2-amines were tested in High-throughput screening for their pesticidalactivities. Then the preliminary bioassays for insecticidal activity among compounds3f~3hand3n~3o indicated that the mortality rates of compounds3f and3n against T. urticae were53.10%and67.71%at500mg/L. The results of fungicidal screening among compounds3d~3f and3p~3q revealed that the inhibition rates of compounds3e,3f and3p against S.sclerotiorum were61.7%,57.9%and59.8%at25mg/L. The results of herbicidal screeningshowed that the inhibition rates of compound3q against A. theophrasti, A. spinosus L and C.album were40%,50%and50%at2250g ai/ha.