Synthesis And Bioactivities Of Thioglycoside Derivatives

Carbohydrates are the main source for all the organisms to maintain life activities. As the endogenous substances of life, carbohydrates take part in almost all biological processes in vivo. Thioglycosides have been found their place in carbohydrate chemistry and carbohydrate biology as important contents in scientific research. Their lasting popularity stems from a combination of relative ease of synthesis, stability and variety in chemical reaction. Glycosidation of many drugs can reduce toxicity and enhance solubility. Therefore, glycoside compounds in pesticide, medicine and daily industry have wide application prospect. In this article, twenty three novel thioglycoside componds were designed and synthesized, and their fungicidal and herbicidal activities were evaluated.Firstly, the compound 2,3,4,6-tetra-O-acetyl-α-D-bromoglucose was synthesized using D-glucose. Then, thiourea and sodium pyrosulfite were used to synthesize 2,3,4,6-tetra-O-acetyl-1-thiol glucopyranosyl, it was reacted with substituted α-bromo acetophenone and benzyl chloride to obtain eight phenacyl-thioglycoside and three benzyl thioglycoside derivatives. These thioglycosides were oxygenated with mCPBA to get six phenacyl-sulfonyl-glucoside and two benzyl-sulfonyl-glucoside derivatives. Further more, two phenyl thioglycoside and two phenyl-sulfonyl-glucoside derivatives were synthesized by the reactions of 2,3,4,6-tetra-O-acetyl-α-D-bromoglucose with substituted thiophenol and mCPBA successively. The structures of all the above target compounds were confirmed by IR,1H NMR,13C NMR and elemental analysis.The herbicidal activities against Brassia campestris and Echinochloa crusgalli were evaluated by plate method. Almost all the target compounds exhibited certain herbicidal activities against B. campestris at the concentration of 100 μg/mL. The inhibitory rates of the compounds 8a,8c,8e,9a,9e and 11b exceeded 50% against the root of B. campestris, thereinto the rates of 8a and 9e reached 62.5%. And the inhibitory rate of the compound 15b reached 50.6% against the root of E. crusgalli, the rates of 14b and 15b exceeded 50% against the stem of E. crusgalli.The fungicidal activities against Fusarium gramiuearum, Botrytis cinerea, Rhizoctonia cerealis and colletotrichum capsici were evaluated by mycelial growth rate method. The target compounds showed low inhibitory activity at the concentration of 100μ/mL, only one compound 14a showed moderate fungicidal activity with an inhibitory rate of 68.6% against Rhizoctonia cerealis.