Synthesis and biological activities of 1H-indole-1-carboxylic acid aryl esters as a marine antifouling coating

A series of indole-1-carboxylic acid aryl esters was synthesized with indole and substituted phenols as raw materials. The structures of the target compounds were validated by IR and 1H-NMR spectroscopies. The inhibitory activities of the target compounds and their potencies against marine fouling organisms were investigated. The results showed that the target compounds had significant inhibitory effects on the growth of three seaweeds: Isochrysis galbana, Platymonas subcordiformis, and Navicula, and the target compounds also had excellent inhibition on the survival of barnacle larvae. The substituent structure–activity relationships revealed a significant effect on biological inhibition activity: Compounds substituted by electron-withdrawing groups had greater bioactivities than those containing electron-donating groups. Release rate of antifoulant and marine field tests indicated the final compounds had an outstanding antifouling potency against marine fouling organisms.