title: Different pathways for the deoxygenation of the A-ring of natural triterpene compounds.
abstract: Some deoxygenation pathways were tested to remove the hydroxyl groups of the natural triterpenes oleanolic acid and maslinic acid to obtain a practical starting material for the semisynthesis of other interesting organic synthons. Different deoxygenation processes were carried out starting from these triterpenic acids or from several derivatives such as methyl esters and epoxy derivatives. The hydroxyl groups were transformed into some intermediate compounds including xanthyl, thiocarbonyl or tosyl derivatives. The opening of the oxirane ring between C-2 and C-3 was also achieved through different methods using deoxygenating reagents such as Me3SiCl/NaI, WCl4/n-BuLi and Cp2TiCl.
authors.affiliation: Departamento de Quimica Organica, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spain. aparra@ugr.es
authors.forename: Andres
authors.initials: A
authors.lastname: Parra
authors.forename: Pilar E
authors.initials: PE
authors.lastname: Lopez
authors.forename: Andres
authors.initials: A
authors.lastname: Garcia-Granados
mesh_terms: D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry*
chemical_list: D014315:Triterpenes; D010100:Oxygen