62498-83-3Relevant academic research and scientific papers
Beckmann rearrangement within the ring C of oleanolic acid lactone: Synthesis, structural study and reaction mechanism analysis
Froelich, Anna,Bednarczyk-Cwynar, Barbara,Zaprutko, Lucjusz,Gzella, Andrzej
, p. 173 - 181 (2017/02/15)
Synthesis, spectral and X-ray analysis of three compounds, i.e. 3β-acetoxy-12-hydroxyimino-18β-oleanan-28,13β-olide (substrate) and 3β-acetoxy-12-nitrile-12,13-seco-15(14?→?13)-abeoolean-14(27)-en-28,13β-olide and 3β-acetoxy-12-oxo-12a-aza-C-homoolean-13(18)-en-28-oic acid (Beckmann rearrangement reaction products) are described. Structural analysis revealed that the oxime group in the ring C in substrate molecule had an E-configuration. The nitrile product with retained lactone group was a result of major transformations within rings C and D of oleanane skeleton. In lactam product free carboxyl group and a double bond in ring D instead of lactone system were formed in Beckmann rearrangement reaction.
The chemical and biological potential of C ring modified triterpenoids
Siewert, Bianka,Wiemann, Jana,K?witsch, Alexander,Csuk, René
, p. 84 - 101 (2014/01/06)
A convenient and elegant route has been developed to separate the natural regioisomers triterpenoids ursolic acid (UA) and oleanolic acid (OA) as well as derivatives thereof. Eleven unknown derivatives of OA were designed, synthesized, and their cytotoxicity was investigated. Further sixteen compounds were prepared to correlate all compounds in a SAR study. It could be shown that C-ring modifications of OA and UA have only a moderate influence onto the cytotoxic activity of the compounds but a significant impact onto the ability to trigger apoptosis in ovarian cancer cells (cell line A2780).
Efficient oxidation of oleanolic acid derivatives using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP): A convenient 2-step procedure towards 12-oxo-28-carboxylic acid derivatives
Salvador, Jorge A.R.,Moreira, Vania M.,Pinto, Rui M. A.,Leal, Ana S.,Paixao, Jose A.
supporting information; experimental part, p. 164 - 169 (2012/04/10)
A new straightforward and high yielding procedure to convert oleanolic acid derivatives into the corresponding δ-hydroxy-γ- lactones, by using the convenient oxidizing agent magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) in refluxing acetonitrile, is reported. In addition, a two-step procedure for the preparation of oleanolic 12-oxo-28-carboxylic acid derivatives directly from Δ12-oleananes, without the need for an intermediary work-up, and keeping the same reaction solvent in both steps, is described as applied to the synthesis of 3,12-dioxoolean-28-oic acid.
Bismuth(III) triflate-based catalytic direct opening of oleanolic hydroxy-γ-lactones to afford 12-oxo-28-carboxylic acids
Salvador, Jorge A. R.,Moreira, Vania M.,Pinto, Rui M. A.,Leal, Ana S.,Le Roux, Christophe
scheme or table, p. 2637 - 2642 (2011/12/01)
The bismuth(III) triflate-based catalytic direct opening of oleanolic hydroxy-γ-lactones affords the corresponding 12-oxo-28-carboxylic acid derivatives, in both acetonitrile and dichloromethane, at reflux, in high yields. Participation of an in situ generated Bronsted acid species from bismuth(III) triflate is most likely involved in the reaction mechanism. Full structural elucidation of the products obtained has been performed by 1D and 2D NMR techniques. Copyright
Synthesis and α-glucosidase inhibitory activity of oleanolic acid derivatives
Qian, Shan,Hai Li, Jiao,Wei Zhang, Yu,Chen, Xin,Wu, Yong
scheme or table, p. 20 - 29 (2010/09/18)
Glucosidations of oleanolic acid (1) and its dihydroxy-olide derivatives (2) were carried out to provide eight glycosides. All synthesized compounds were evaluated by in vitro α-glucosidase inhibitory activity assay. 3-Acetyl dihydroxy-olide oleanolic der
Oxyfunctionalization products of terpenoids with dimethyldioxirane and their biological activity
Ogawa, Shoujiro,Hosoi, Keiji,Ikeda, Noriaki,Makino, Mitsuko,Fujimoto, Yasuo,Iida, Takashi
, p. 247 - 250 (2007/10/03)
Oxyfunctionalization of the bioactive terpenoids, ursolic acid acetate (1), oleanolic acid acetate (5), lupeol acetate (12), and kaurenic acid (17), with dimethyldioxirane (DMDO) was investigated. Treatment of the terpenoids with DMDO under mild conditions afforded a variety of oxidation and oxydegradation products to yield naturally occurring and/or novel compounds in one step. After chromatographic separation, the structures of the individual isolated products were determined using spectroscopic methods including several homonuclear ( 1H-1H) and heteronuclear (1H-13C) shift-correlated 2D-NMR techniques. The inhibitory activity of the terpenoid derivatives against α-glucosidase was investigated and compounds 1, 3, 7, and 9 were found to exhibit potent activity.
Partial synthesis of C-ring derivatives from oleanolic and maslinic acids. Formation of several triene systems by chemical and photochemical isomerization processes
García-Granados, Andrés,López, Pilar E.,Melguizo, Enrique,Parra, Andrés,Simeó, Yolanda
, p. 1491 - 1503 (2007/10/03)
Some triterpenic compounds modified in C-ring were semi-synthesised from oleanolic acid contained in the solid waste of olive-oil pressing. The corresponding esters of oleanolic and maslinic acids rendered products with a diene system, which led to oleantrienes resembling previtamin D2 by an electrocyclic reaction. Chemical and photochemical isomerization of these compounds yielded two different trienes with similar structure to tachysterol and vitamin D2.
OXIDATIVE TRANSFORMATIONS OF TRITERPENOIDS OF THE URSANE AND OLEANANE SKELETA WITH HYDROGEN PEROXIDE. INTRODUCTION OF 11,12-DOUBLE BOND AND 13(28)OXIDE MOIETY IN THE URSANE SYSTEM
Majumder, P. L.,Bagchi, A.
, p. 649 - 656 (2007/10/02)
Treatment of oleanolic acid acetate (1b) with H2O2 in boiling HOAc gave the epoxy-γ-lactone 2b and the 12-hydroxy-γ-lactone 3b.The total absence of the 12-ketodihydro acid 4b among the oxidation products of 1b has been rationalised.The results of this reaction with several isomeric pairs of triterpenoids of the ursane and oleanane skeleta bearing functional groups at C-17 other than a carboxyl group show that for any appreciable oxidation involving the intermediacy of a 12β,13β-epoxide 6a or 6b, the 17-carboxyl group is an essential requirement.An intramolecular epoxidation of 12,13-double bond of 1a and 1b by 17-percarboxy acid formed in situ has been envisaged.The reactions aiming at introducing 11,12-double bond and 13(28)-oxide moiety in the ursane system are described.The desired compound 2c was obtained by treatment of the triol 1p with TsOH.With H2O2/TsOH, 1p, however, gave besides 2c, the rearranged product 8a.The difference in the chemical behaviour of 1p and 1q has been explained.Treatment of 2e with H2O2 in boiling HOAc gave the epoxide 2f.The mechanism of formation of 2a and 2b is discussed in the light of this observation.
