Search results for "Santonin"
showing 10 items of 24 documents
Synthesis of 3-Oxa-guaianolides from Santonin
2000
Abstract This article reports on the transformation of santonin into two C10-epimeric 3-oxa-guaianolides which are 8-deoxyderivatives of several natural 3-oxaguaianolides isolated from Achillea species. The synthesis involved the photochemical rearrangement of the eudesmane skeleton into a guaiane skeleton and the transformation of the cyclopentane ring into a furan moiety with the concomitant loss of C3. Comparison of the NMR data of the synthetic products with those of the natural products confirms the β orientation of the hydroxyl group at C10 in the products isolated from Achillea.
ChemInform Abstract: A Non-Catalyzed Ring-Opening Aminolysis Reaction of Sesquiterpene Lactones.
2010
Abstract Santonin (1) and other sesquiterpene lactones (6–10) react cleanly with pyrrolidine at room temperature to afford γ-hydroxyalkylamides, which by elimination with mesyl chloride in pyridine-benzene at 80°C give unsaturated alkylamides.
A Molecular Electron Density Theory Study of the Chemoselectivity, Regioselectivity, and Diastereofacial Selectivity in the Synthesis of an Anticance…
2019
The [3 + 2] cycloaddition (32CA) reaction of an &alpha
Stereoselective Synthesis of (+)-11βH,13-Dihydroestafiatin, (+)-11βH,13-Dihydroludartin, (−)-Compressanolide, and (−)-11βH,13-Dihydromicheliolide fro…
2002
Starting from 2 and 3, obtained from santonin (1), we have synthesized natural guaianolides 4-7. Chemoselective epoxidation of 2 gave (+)-11betaH,13-dihydroestafiatin (4), and epoxidation of 3 followed by regioselective elimination of the hydroxyl group afforded (+)-11betaH,13-dihydroludartin (5). Sharpless' mild regioselective ring-opening of 4 and 5 followed by hydrogenolysis yielded (-)-compressanolide (6) and (-)-11betaH,13-dihydromicheliolide (7), respectively.
ChemInform Abstract: Synthesis of Elemane Bis-lactones Structurally Related to Vernolepin.
2010
Abstract The chemical transformation of santonin into an elemane bis -lactone structurally related to the antitumour compound vernolepin is reported. The transformation of ring A of santonin into a hemiacetal δ-lactone was achieved in eleven steps. The spectroscopic characteristics of the synthetic product obtained in this way revealed that the proposed structure for the natural product should be revised.
ChemInform Abstract: The Synthesis of Bioactive Sesquiterpenes from Santonin
2010
Abstract This article reviews the literature published in the last decade dealing with the transformation of α-santonin into bioactive or potentially bioactive sesquiterpenes. A number of syntheses starting from 8α-hydroxysantonin (artemisin) have also been included. Special emphasis has been placed on synthesized products that show biological activity. Major advances in this field include the application of new reagents and methodologies for the structural modification of the santonin skeleton and functionality, and its transformation into other sesquiterpenes, especially sesquiterpene lactones. The review has been organised into five parts: 1. Introduction: An overview of the structure an…
ChemInform Abstract: Synthetic Studies Toward Natural Furanosesquiterpenoids from Santonin. Synthesis of (+)-1,2-Dihydrotubipofuran.
2010
Abstract Santonin (1) was converted into (+)-1,2-dihydrotubipofuran (13) via a synthetic pathway involving a very easy preparation of 7,11-ene-8,12-olide and 8,12-furan moieties and A-ring elaboration on the eudesmane framework.
ChemInform Abstract: Synthesis of (+)-Isoalantolactone and (+)-Isoalloalantolactone from (-) -Santonin.
2010
Abstract This paper reports on the chemical conversion of (−)-santonin into (+)-isoalantolactone and (+)-isoalloalantolactone involving functionality transfer from C 6 to C 8 , refunctionalization of the ring A and the formation of the α-methylene-8 β,12-olide moiety.
ChemInform Abstract: Synthesis of Two Natural 8-Oxo-β-cyperone Derivatives from (-)- Santonin.
2010
Abstract This paper reports on the chemical transformations of (−)-santonin into (+)-8-oxo-β-cyperone and (+)-12-hydroxy-8-oxo-β-cyperone involving 8-oxo group introduction and elaboration of the side chain.
ChemInform Abstract: Synthesis of Elemane Bis-lactones from Santonin - Synthesis of the Reported Structure of seco-Isoerivanin Pseudo Acid and Formal…
2001
The synthesis of the reported structure for seco-isoerivanin pseudo acid (1) and of an elemane bis-lactone 5 from santonin (4) through a common vinylic precursor 12 is described. Compound 5 is a known intermediate in a previous synthesis of the antitumor compound (+)-8-deoxyvernolepin (3). The vinyl group of 12 underwent a regio- and diastereoselective anti addition of an external electrophile and an intramolecular condensation to yield either the selenolactone 13 or the hydroxylactone 17. The lactones 13 and 17 served as key intermediates in the total synthesis of 1 and 5 respectively. A revision of the structure of seco-isoerivanin pseudo acid to the C-10 epimer is suggested on the basis …