Synthesis Of The Glycoconjugates And Study Of Their Herbicidal Activities

The saccharine molecules with active functions, widely existing in the nature,are displaying many kinds of functions. It is these biologic functions that arousepeople enormous interests. The analog synthesis of natural carbohydratecompounds by using carbohydrate compounds as modifiers only then can developfast. To introduce such biologic functional carbohydrate compounds to themodified goal molecules with different bond-connect ways, enabling two parts ofmembers to display respective biologic activity function as far as possible, is thefinal goal of carrying on the carbohydrate synthesis.With the enhancement of human environmental protection consciousness,active functional organic compounds which are non-toxic, harmless, andbiologically degradable gradually substitute for the original active compounds.Herbicides are the indispensable organic compounds for agricultural development.Along with their amounts used unceasingly increasing, the environmented bearingcapacity caused by the deposition of organic compounds from those herbicidesdrainage runs down unceasingly. To seek methods for solving this question is anurgent topic. This article hoped to introduce the carbohydrate compounds to activefunctional herbicide compounds, to display functions of each active part, andfinally to obtain kinds of environmental friendly functional compounds.Firstly,in the article we used glucosyl isothiocyanates as the sugar baseprovider and used series of anline compounds as the nucleophilic reagents tosynthesize series of glycosyl thiourea compounds, then carried out the preliminarytests to their herbicidal activities. The result turned out that, glycosyl anlinethiourea compounds present the good restraining activities. When there areelectron-withdrawing groups in the benzene ring structure, it shows good results.When electron-withdrawing groups are in the medium position of the benzenering structure, the active results present the biggest.Secondly, we used series of glycosyl isothiocyanates compounds as the sugarbase provider and used 2-amino-4, 6-dimethylpyrimidine and thiosemicarbazidecompounds as the nucleophilic reagents to conduct the synthesis from which weobtain the series of glycosyl urea compounds. From the preliminary herbicidalactive data, we may see that when standing erect bond exists at sugar ring in thecompound structure, activity has been improved, when the number of sugar unitincreases, activity has the tendency which obviously advances. The reason is thatthe compound structure approximately approaches the plant epidermal tissuestructure, which causes the measured compounds to be able to be adequatelyabsorbed by plant bodies then to display medicine activities.Based on the three series inspected compounds, we introduced thecarbohydrate compounds directly by the sugar ester structure to the herbicideswith small molecular compounds, and then obtained two sugar ester seriescompounds. In 2, 4-dichlorophenoxyacetic acid and in 2-methyl-4-chloro-phenoxyacetic acid series sugar esters, we carried on the herbicidal activities testsby the different concentration gradient to the product. From the showed activedata, the activity of carboxylic acid ester which decorated by the sugar baseextremely approaches activity in original medicine carboxylic acid. When theconcentration reduces, the reducing variance is not very big. However,considering the solubility in the water, the sugar ester compounds have the greatsolubility. Compared to phenoxyacetic acid that does not dissolve in the water wehave got the very big progress, thus explaining that, the herbicide molecules withcarboxylic acid structures decorated by the sugar ester are effective.Finally, we used the glycosylamine as the nucleophilic reagent and usedbromination N-alkoxyalkyl-2, 6-dinitroaniline as the sugar base acceptor toconduct the synthesis from which we obtain series sugar based compounds. In theseparation and depuration process, from N-glucoside and N-galacoside of theN-alkoxyalkyl-2, 6-dinitroaniline we obtain the sugar base compound includingdouble N-alkoxyalkyl-2, 6-dinitroaniline molecules. Researching from the activedata, the activity of the compound including double N-alkoxyalkyl-2,6-dinitroaniline molecules is obviously lower than that of includingmonomolecule. The author considers that when the sugar based derivativesincluding double N-alkoxyalkyl-2, 6-dinitroaniline molecules entered plant bodies,in the enzyme activity position spot due to the crowdedness of molecules in thespace, they cannot display the highest restraining activities, which manifestsherbicidal activities decline.In the paper the obtained compounds all confirmed by NMR and MS, and allcompounds display good activities through preliminary herbicidal activity tests.From the initial inspection to direct introduction of the sugar ring to the herbicidalactive molecules as well as to the results of preliminary herbicidal activity, it isdemonstrated that the use of carbohydrate compounds to carry on modifying is afeasible route. While enhancing the solubility, due to the existence ofcarbohydrate compounds the organic matter is very easy to degrade in theenvironment, which makes the pressure created to the environment also greatlyreduce. The application of the decoration of sugar base to the herbicidal chemicalsbecomes possible.