Research On Synthesis And Evolution Of Oxadiazine Insecticides

Indoxacarb (Methyl 7-chloro-2, 5-dihydro -2-[[(methoxycarbonyl)[4-(trifluoro -methoxy)-phenyl]amino]carbonyl]-indeno[1,2-e][1,3,4]oxadiazine-4a(3H)-carboxylate), a typical oxadiazine insecticide, is discovered by Du Pont as a new class of chiral sodium blocker and comes into the market in 2001. As a broad spectrum insecticide indoxacarb combines a favourable environmental profile, which includes safety to human beings, environment, crops and non-drone creatures, with exceptional activity on lepidoptera. Indoxacarb has characteristics of new structure, special function mechanism and low dosage which make it one of preferred substitutes for organophosphorus insecticide, and it has been hot researched all over the world.In this studies, indoxacarb is synthesized by ten steps with the raw material of p-chlorophenylacetic acid and achieved the total yield of 29.5% and the e.e. value of (+)indoxacarb reaches to 71.1% by separation by reversed chiral-HPLC .Intermediate hydrazinecarboxylate is synthesized by using hydrazine and benzyl chloroformate as raw materials, effects of reaction conditions such as solvent, ratio of reactants, concentration, temperature and reacting time on yield are studied. The yield of hydrazinecarboxylate is 80.7% and the purity is over 98%. Another intermediate methyl (chlorocarbonyl)[4-(trifluoromethoxy)phenyl]carbamate is synthesized using bis(trichloro methyl)carbonate instead of phosgene with the yield of 60.8% and the purity of over 99%.The mild experiment with good selectivity shows that the substitution can avoid the poison of phosgene. All compounds synthesized are characterized by means of MS and 1H-NMR.The evolution of other oxadiazine secticides is investigated. Methyl 7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[2-chloro-pyridyl]amino]carbonyl]indeno[l,2][l,3,4] oxadiazine-4a(3H) carboxylate and methyl 7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[ 6-chloro-2-methyl pyridyl]amino] carbonyl]indeno[l,2-][l,3,4]oxadiazine-4a(3H)-carboxylate are designed according to bioisosterism and are total synthesized.The two compounds are identified by high resolution MS and 1H-NMR.