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3-Ishwarone, a rare ishwarane sesquiterpene from Peperomia scandens Ruiz & Pavon: structural elucidation through a
Fernando M dos S Junior1, Leosvaldo S M Velozo, Erika M de Carvalho
1Núcleo de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil. mbamorim@nppn.ufrj.br.
Abstract:
3-Ishwarone, (1), a sesquiterpene with a rare ishwarane skeleton, was isolated from Peperomia scandens Ruiz & Pavon (Piperaceae). Its structure was unambiguously determined by 1D- and 2D-NMR and infrared analyses, as well as by comparative theoretical studies which involved calculations of 13C-NMR chemical shifts, using the Density Functional Theory (DFT) with the mPW1PW91 hybrid functional and Pople's 6-31G(d) basis set, and of vibrational frequencies, using the B3LYP hybrid functional and triple ζ Dunning's correlation consistent basis set (cc-pVTZ), of (1) and three of its possible diastereomers, compounds 2-4.
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