Novel Microwave-Synthesized Biomass-Derived Furanics as Effective Sustainable Antifouling Agents

The solid phase microwave-assisted eco-efficient synthesis of phenyl esters with acid halides including furoyl chloride (FO) and thiophenecarbonyl chloride (FS) was achieved in this work. A stoichiometric amount of the corresponding chloride was sufficient to carry out the reaction with yields between 90% and 95% in 5 min, with simple products purification by recrystallization in ethanol. In the search of new sustainable alternatives to copper-based antifouling paints, eight compounds were synthesized, e.g., 2-isopropyl-5-methylphenyl thiophene-2-carboxylate (1), 2-isopropyl-5-methylphenyl furan-2-carboxylate (2), phenyl thiophene-2-carboxylate (3), phenyl furan-2-carboxylate (4), 4-methylphenyl thiophene-2-carboxylate (5), 4-methylphenyl furan-2-carboxylate (6), 3,4-dimethylphenyl thiophene-2-carboxylate (7), and 3,4-dimethylphenyl furan-2-carboxylate (8). Their antifouling activity was evaluated in field trials. Field antifouling tests carried out at Mar del Plata harbor for 90 days showed that, except for compound (8), all bioderived furanics were effective in strongly reducing the settlement of the most conspicuous worldwide calcareous macrofouler Balanus amphitrite. © 2020 American Chemical Society.