Estudo químico de Ochroma lagopus swartz e síntese de amidas derivadas da piperina, com avaliação de suas respectivas atividades inseticida

Abstract

In this work were described sixteen natural compounds isolated from Ochroma lagopus, among which, nine are new. These compounds were isolated by column chromatography on silica gel, and some fractions of the ethanolic extract from the heartwood, after repeated column chromatographics, were also submitted to semipreparative-scale recycling HPLC. The structures of these compounds were elucidated by detailed IR, MS, one- and two-dimensional 'H-NMR and '^C-NMR spectroscopic studies. The novel natural products isolated were lignans named: boehmenan B, C, and D, and carolignan A, B, C, D, E and F. The other compounds identified were boehmenan, secoisolariciresinoyl diferulate, P-sitosterol, stigmasterol, daucosterol, stigmasterol-3-(9-P-D-glycoside, and mannitol. Extracts and fractions of O. lagopus were tested in order to evaluate their possible activities against several insect species. However, they showed no insecticidal activity against the tested species. In the second part of this work the natural amides, piperine and piperiline, were isolated from black pepper (^Piper nigrum), and the following piperine derivatives were synthetized: N-ethylpiperamide, N,N-diethylpiperamide, N,Ndiisopropylpiperamide, N-butylpiperamide, N-isobutyl-piperamide, N-isopentylpiperamide, N-cyclohexylpiperamide, N-isopropyl-piperamide, N-pentylpiperamide, N-hexylpiperamide, N-decylpiperamide, N-adamantylpiperamide, N-[2- (piperidin-l-yl)ethyl]piperamide, N-[2-(morpholin-4-yl)ethyl]piperamide, N-(lbenzylpiperidin- 4-yl)piperamide and N-[2-(pyridin-2-yl)ethyl]piperamide. For the last nine compounds it was not found any report in the literature. All these amides were submitted to biological assays in order to evaluate their activities against Acanthoscelides obtectiis Say, Ascia monuste orseis Latr., Brevicoryne brassicae L., Cornitermes cumulam Kollar, Protopolybia exigua DeSaus, Sitophilus zeamais Mots e Rhizopertha dominica Fabr. Most of the amides, natural and synthetic, showed insecticidal activity for at least one species. Among these species, A. monuste e B. brassicae were the most suceptible to this group of compounds.