Synthesis And Activities Study Of N-Nitro-N-(2, 4, 6-Trinitrophenyl) Urea Derivatives As Plant Growth Regulators

N-nitroaniline and N-nitro urea compounds have herbicidal activity as well as plantgrowth regulating activity. The N-nitration of 2, 4-dinitroaniline was investigated. Theresults showed that: When 2, 4-dinitroaniline was treated with acetyl nitrate in glacialacetic acid at 15℃, N-nitro-2, 4-dinitroaniline was produced, with productivity 78.51%.But when it was treated with acetyl nitrate in sulfuric acid at 25℃, N-nitro-2, 4,6-trinitroaniline was produced, with productivity 75.16%. Both of the structures wereconfirmed by IR, ¹H NMR, MS spectra and elemental analysis. The effect oftemperature and solvent on the reaction has been investigated.N-nitro-2,4,6-trinitroaniline reacted with bis(trichloromethyl) carbonate leading toacyl chloride, then treating acyl chloride with substituted aniline gave thirteen novelN-nitro-N-(2, 4, 6-trinitrophenyl) urea derivatives. Their structures were confirmed by¹H NMR, IR, MS and elemental analysis. Their general formula was as follows:R= a: H, b: 2-Cl, c: 3-Cl, d: 4-Cl, e: 2-CH₃, f: 4-CH₃, g: 2, 4-dimethyl,h: 2-F, i: 3-F, j: 2,6-difluoro, k: 2-NO₂, 1: 3-NO₂, m: 4-NO₂.Physicochemical constant, spectrum properties and the synthesis conditions havebeen investigated systematically. Results showed that: The method of acyl chlorideususlly gave high yield, for example the productivities of compounds b, e, g, j, 1 wereall above 80%. But the method of isocyanate couldn't produce the target compounds.The activities of the urea derivatives were tested at the concentration of 20 mg·kg^-1,50 mg·kg^-1, 100 mg·kg^-1, 500 mg·kg^-1, 1000 mg·kg^-1 on rape,rice,barnyard grass andAmaranthus retroflexus L. The structure parameters of urea derivatives were caculatedusing PM3 approach in Gaussian03 program. The correlation analysis between theirstructures and biological activities was analyzed. Preliminary biological tests showed that:(1) The possible action spot of the urea derivatives on the tested plants was root. (2) Theurea derivatives showed strong inhibitory activity against rape,rice, barnyard grass andAmaranthus retroflexus L at the concentration of 500 mg·kg^-1 and 1000 mg·kg^-1. (3)Compound j showed strong inhibition on the tested plants. (4) The electronic effect ofcompounds a, c, d, f, i, 1, m had good correlation with their biological activities at theconcentration of 500 mg'kg-1 on rape:the smaller of electron atmosphere density in rightbenzene ring, the bigger the inhibitory activity on living ratio and stem. (5)The freshweight of rape had some correlation with the longer of bondâ… : the longer of bondâ… , thebigger the inhibitory activity on fresh weight.