O teor de tocoferol de óleo de castanha-do-Brasil proveniente de diferentes regiões da Amazônia (Manicoré-AM, Rio Preto da Eva-AM, São João da Baliza-RR, Caroebe-RR, Belém-PA e Xapurí-AC) foi investigado através de cromatografia líquida de alta eficiência em fase normal. Em todos os óleos autênticos, dois isômeros, α- e γ-tocoferóis (37,92-74,48 µg g-1, 106,88-171,80 µg g-1, respectivamente), foram observados, e seus níveis foram relativamente constantes em todos os óleos destas origens geográficas, o que pode distinguir o óleo de castanha-do-Brasil dos óleos de outras plantas, em termos de autenticidade. Os óleos comerciais de castanha-do-Brasil também foram avaliados e alguns mostraram teor de tocoferol muito diferente que o dos óleos autênticos. Portanto, sugere-se que o perfil de tocoferol do óleo de castanha-do-Brasil pode ser usado como marcador químico para controle de qualidade e autenticação.

The tocopherol content of Brazil nut oil from different Amazon regions (Manicoré-AM, Rio Preto da Eva-AM, São João da Baliza-RR, Caroebe-RR, Belém-PA, and Xapurí-AC) was investigated by normal-phase high-performance liquid chromatography. For all authentic oils, two isomers: α- and γ-tocopherols were observed (37.92-74.48 µg g-1, 106.88-171.80 µg g-1, respectively), and their levels were relatively constant among the oils having these geographic origins, which would enable to distinguish Brazil nut oil from other plant oils for authentication purposes. Commercial Brazil nut oils were also evaluated, and some of these oils demonstrated a tocopherol content that was very different from that of the authentic oils. Therefore, we suggest that the tocopherol profile of Brazil nut oil can be useful chemical marker for quality control and authentication.

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.