Síntese de fenilcarbamatos e carbamatos derivados do líquido da casca da castanha de caju (LCC) e posterior avaliação de suas atividades anticolinesterásica e moluscicida

Abstract

This work involved the synthesis of N-methylcarbamates, including preparation of this class of compounds from the anacardic acids (7), a main constituent of cashew nut shell liquid (CNSL). The carbamates synthesized and their synthetic intermediates were anticholinesterase and molluscicidal potential evaluated. Thus, this work begins with a literature review that addresses the LCC in then was discuss some methodologies related to the synthesis of carbamates. The preliminary phase of work included the study experimental synthetic route for the preparation of amino N-methylcarbamates (152) from m-cresol (151). Obtaining the first synthesis intermediates (9) was initiated by carbamatation of the m-cresol (151). The intermediary then had obtained his position benzylic bromine to produce alkyl halide (176), which was subsequently amine to complete the synthesis of amino N-methylcarbamates (152) sought. Giving following the work, and already knowing the reaction conditions for synthesis of amino N-methylcarbamates from phenols, were initiated experiments to obtain the amino N-methylcarbamates (8) from anacardic acids (7), a constituent of CNSL. At first, the cardanols (12) were prepared from the decarboxylation of anacardic acids (7) and then it was hydrogenated to obtain a phenol, the cardanol hydrogenated (18). The cardanol hydrogenated (18) underwent carbamatation using methyl isocyanate (173), carbamate obtained (177) had its benzylic position bromine and the alkyl halide (178) generated was finally amine with dimethylamine (159). After the four steps synthetic succession, the desired product was obtained with 17% yield overall. Since the successful preparation of 1'-dimethylamino N-methyl hidrocardanilcarbamate (8), were synthesized other carbamates using methyl isocyanate (173). Among these are carbaryl (2) and metolcarbe (9), commercial pesticides and their analogues (10) and (11). N-methylcarbamates (177) and (181) derived from the CNSL, were also prepared using the same methodology. The ability to inhibit AChE and molluscicidal activity of carbamates were then prepared evaluated, and the amino N-methylcarbamates (8) showed an IC50 of 0.17 mM, slightly higher than acetylcholinesterase activity than the metolcarbe (9), whose IC50 value is equal to 0.90 mM. The amino N-methylcarbamates (8) also showed moderate potential to eliminate the mollusk species B. glabrata, and its lethal concentration, LC10, LC50 and LC90 of 7.22 ppm (0.0178 mmol / L), 12.81 ppm (0.0317 mmol / L) and 22.73 ppm (0.0562 mmol / L), respectively.