title: Hydrogenation of the exocyclic olefinic bond at C-16/C-17 position of ent-kaurane diterpene glycosides of Stevia rebaudiana using various catalysts.
abstract: Catalytic hydrogenation of the exocyclic double bond present between C16 and C17 carbons of the four ent-kaurane diterpene glycosides namely rebaudioside A, rebaudioside B, rebaudioside C, and rebaudioside D isolated from Stevia rebaudiana has been carried out using Pt/C, Pd(OH)2, Rh/C, Raney Ni, PtO2, and 5% Pd/BaCO3 to their corresponding dihydro derivatives with 17α and 17β methyl group isomers. Reactions were performed using the above-mentioned catalysts with the solvents methanol, water, and ethanol/water (8:2) under various conditions. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data, including a comparison with reported spectral data.
authors.affiliation: Organic Chemistry Department, Global Research and Development, The Coca-Cola Company, Atlanta, GA 30313, USA. iprakash@coca-cola.com
authors.forename: Venkata Sai Prakash
authors.initials: VS
authors.lastname: Chaturvedula
authors.forename: Indra
authors.initials: I
authors.lastname: Prakash
mesh_terms: D002384:Catalysis; D045786:Diterpenes, Kaurane / Q000737:chemistry* / Q000302:isolation & purification; D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry*; D006865:Hydrogenation; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D036625:Stevia / Q000737:chemistry*
chemical_list: D045786:Diterpenes, Kaurane; D006027:Glycosides; D008670:Metals; D012997:Solvents
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