Synthesis And Antifouling Of N-Formyl/sulfonyl Substituted Indoles

As marine environmental protection is highly prized, the research of environmentally friendly antifoulants is of great significance. Indole derivatives extracted from marine organism has attracted widespread attention due to the antifouling activity and good biodegradability.The article introduced the current situation about marine antifouling and the application of indole compound on marine antifouling. A total of three series of compounds were designed based on the Indole (YD), which included Indole-1-formic acid ester, Indole-1-formic acid phenyl ester, N-methanone/phenylsulfonyl-indole. Some of them have never been reported so far and we researched on their antifouling performances. TR and1H NMR analysis confirmed their structures. Through a succession of experiments about the inhibition of three kind of marine algae’s growth(isochrysis galbana, platymonas subcordiformis and navicula), the inhibition of barnacle larvae’s growth, seepage rate of antifouling agent and immersion test of shallow sea, We explored the relevance between the structure of prepared compounds and antifouling activities.The result of algal inhibiting activity test showed that most of these indoles can inhibit the activity of the three kinds of Marine algae. The toxic effects were better that electronegativity of connect the R radical more stronger. The better inhibitory activity was on navicula, the weaker inhibitory activity was on isochrysis galbana, the intermedius inhibitory activity was on platymonas subcordiformis.The result of barnacle larvae growth inhibition test demonstrated that exhibitting a positive correlation with the number of carbon in the linking group and the complexity of the compounds. The growth inhibitory effect of compounds with an electron-withdrawing group on the benzene ring was better than those with electron-donating group. For the same substituem groups,the inhibitory effect of ortho-position better than meta-position, also meta-position was better than para-position.The respectively LC50value of Indole-1-formic acid ester, Indole-1-formic acid phenyl ester, N-methanone-indole and N-phenylsulfonyl-indole was506-2664μg/L,403-2543μg/L and479-2287ug/L.The result of shallow sea immersion test showed that after90days shallow sea immersion test, the content of fouling organism (barnacle for example) adhered on the test panels with10%antifouling coating was obviously lower compared to the control group. The antifouling effect basically meet the requirements.The result of seepage rate experiment showed that all of the compounds have stability seepage rate.The respectively range of leakage rate of Indole-1-formic acid ester, Indole-l-formic acid phenyl ester, N-methanone/phenylsulfonyl-indole was0.9-1.9μg·cm-2·d-1,1.2-1.9μ·cm-2·d-1and1.2-1.5μg·cm-2·d-1.