10.1016/S0031-9422(00)97297-2
This research aimed to identify and isolate the chemical constituents of various plant species, including Diospyros buxifolia, D. tomentosa, D. ferra, D. lotus, Balanites aegyptiaca, Rhus parviflora, Polygonum recumbens, and Pyrus pashia. The study involved the extraction and chromatographic separation of compounds from these plants, leading to the identification of various triterpenes, steroids, and other chemical constituents such as friedelin, epi-friedelinol, p-sitosterol, lupeol, betulin, betulinic acid, and maslinic acid, among others. The research concluded with the detailed characterization of these compounds, including their melting points, optical rotations, and spectroscopic data, which contribute to the understanding of the phytochemical profiles of the studied plants and may have implications for their medicinal properties.
10.1021/jo01017a002
The research explores novel rearrangement reactions of pentacyclic triterpenes, aiming to develop a general approach for synthesizing naturally occurring triterpenes like friedelin from α- and β-amyrin. The study investigates oxidative rearrangements, such as the conversion of β-amyrin to taraxerene derivatives through photooxidation and chemical reactions involving hydrogen peroxide and acids. Key chemicals include α- and β-amyrin, chromic acid, lithium aluminum hydride, and various reagents like peracetic acid and osmium tetroxide. The research concludes that specific oxidative conditions can drive rearrangements to less stable carbon skeletons, providing a method for synthesizing complex triterpenes. This approach involves coupling rearrangement steps with exothermic reactions, such as electrophilic addition to carbon-carbon double bonds, to overcome thermodynamic barriers and achieve desired triterpene structures.
