A capacidade antioxidante, o conteúdo fenólico total e os elementos minerais foram investigados, in vitro, nas cascas dos frutos de Myrciaria cauliflora. A capacidade antioxidante foi analisada pelos métodos difenilpicrilhidrazina (DPPH), [2,2'-azino-bis(3-etilbenzotiazolin)-6-sulfônico] (ABTS), poder redutor do íon férrico (FRAP) e β-caroteno. Os ensaios baseados nos métodos DPPH (EC50 = 3,18 g amostra/g DPPH), ABTS•+ (1017 μmol Trolox/g amostra), FRAP (1676 µM Fe2SO4/g amostra) e β-carotene/ácido linoleico (70% de inibição da oxidação) indicam alta capacidade antioxidante dos extratos das cascas dos frutos dessa planta. O método Folin-Denis foi mais eficiente quando comparado com Folin-Ciocalteu para a determinação de compostos fenólicos em diferentes solventes. Extrações com soluções de 4:1 metanol-água, 4:1 etanol-água, 3:2 etanol-água e 3:2 acetona-água, usando o método Folin-Denis, exibem alto conteúdo de compostos fenólicos (18,95; 14,06; 12,93; 11,99 mg GAE/g, respectivamente). Potássio é o elemento encontrado em maior proporção nas cascas deste fruto, seguido pelo fósforo, cálcio, magnésio e ferro. Como resultado, cascas do fruto de M. cauliflora podem ser consideradas uma importante fonte de antioxidantes naturais e elementos essenciais de fácil acesso à população e aplicação pela indústria de alimentos.

The in vitro antioxidant capacity, total phenolic content and mineral elements of the fruit peel of Myrciaria cauliflora were investigated. The antioxidant capacity was analyzed by the diphenylpicrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and β-carotene methods. The assays based on the DPPH (EC50 = 3.18 g sample/g DPPH), ABTS•+ (1017 μmol Trolox/g sample), FRAP (1676 µM Fe2SO4/g sample) and β-carotene/linoleic acid (70% of oxidation inhibition) methods indicated a high antioxidant capacity of the fruit peel extract of the plant. The Folin-Denis method was more efficient in determining the total phenolic compound contents in the different solvents than the Folin-Ciocalteu one. Extractions made with 4:1 methanol-water, 4:1 ethanol-water, 3:2 ethanol-water and 3:2 acetone-water solutions using the Folin-Denis method exhibited high contents of phenolic compounds (18.95, 14.06, 12.93 and 11.99 mg GAE/g, respectively). Potassium was the major element found in the fruit peel, followed by phosphorus, calcium, magnesium and iron, in that order. As a result, the fruit peel of M. cauliflora can be considered as an important source of natural antioxidants and essential elements of easy access for the population and for application in the food industry.

The stability of N-propylbutanimine (1) was investigated under different experimental conditions. The acid-catalyzed self-condensation that produced the E-enimine (4) and Z-inimine (5) was studied by experimental analyses and theoretical calculations. Since the calculations for the energy of 5 indicated that it had a lower energy than 4, yet 4 was the principal product, the self-condensation of 1 must be kinetically controlled.

The NMR conformational study of 4',7-di-hydroxy-8-prenylflavan 1 was carried out in acetone-d6, DMSO-d6 and CDCl3 which enabled the proposition of three conformations, namely 1a, 1b and 1c, differing in the position of the prenyl group. Geometry optimizations performed using AM1 method showed that 1a (deltaHf = -86.2 kcal/mol) is as stable as 1b (deltaHf = -85.1 kcal/mol) and 1c (deltaHf = -85.4 kcal/mol). When the solvent was included, the calculations showed that the solute-solvent interactions could be explained either in the light of the electronic intermolecular delocalization or the electrostatic character between solute and solvent. Theoretical calculations (HF/6-31G*, deltaFT/BLYP/6-31G*, and deltaFT/B3LYP/6-31G*) showed that the combination of these types of interactions present in each solute-solvent system, dependent on the chemical properties of the solvent, lead to different spatial arrangements of the prenyl group, which in turn determined the conformation of 1.

Despite the fact that boranes are frequently used in amide reductions, the reaction mechanisms of the involved are note well known. This work presents the results of a bibliographic search on probable amide reduction mechanisms and an analysis of the existing literature. Steric and electronic effects were considered in light of reactivity since it could be concluded that the formation of intermediates and products depends mainly on the substitution patterns of both the boron and nitrogen atoms. Otherwise, results described in the literature for the reactions of boranes, sodium borohydride, lithium aluminum hydride, alkylboranes or haloboranes with others functional groups such as carboxylic acids, esters, ketones and alkenes were analysed with the aim to obtain something about the N-substituted amide reactions employing boranes.