Search results for "Terpene"

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: Ring-Opening Aminolysis of Sesquiterpene Lactones: An Easy Entry to Bioactive Sesquiterpene Derivatives. Synthesis of (+)-β-Cype…

2010

Abstract Santonin ( 1 ) and other sesquiterpene lactones ( 2–3 ) react with pyrrolidine and other cyclic secondary amines to afford γ-hydroxyamides, which by elimination with mesyl chloride in pyridine-benzene at 80°C give unsaturated amides 4a-4c, 5a-5c and 6 . Starting from amides 5a-5c a series of bioactive compounds against Locusta migratoria have been prepared, differing in the oxidation states of the C-3 and C-12 carbon atoms. Starting from amides 5a and 6 two conjugated diene eudesmanes (+)-β-cyperone ( 15 ) and (−)eudesma-3,5-diene ( 19 ) have been prepared involving an elaboration of the amide group of the side chain of the eudesmane skeleton.

Synthesis of β-methylfurolabdanes from (+)-sclareolide

2002

An efficient synthesis of the methylfurolabdane 3 from (+)-sclareolide (6) via the hydroxyalkenes 12 is reported. Alternative modes of cyclization of 12 allowed the synthesis of methyldihydrofuran derivatives 4 and 5 and methyltetrahydrofuran derivatives 15. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002)

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: New Route to Herbertanes via a Suzuki Cross-Coupling Reaction: Synthesis of Herbertenediol.

2010

Abstract The synthesis of herbertenediol, a relevant member of the herbertane-type sesquiterpene family, is described. The synthesis is based on a new general approach to this group of sesquiterpenes where the herbertane skeleton is constructed using a Suzuki cross-coupling reaction and a [2,3]-sigmatropic Still–Wittig rearrangement as key synthetic steps.

ChemInform Abstract: Aromatic Abietane Diterpenoids: Total Syntheses and Synthetic Studies

2015

New insights into the bioactivity of cucurbitacins

2005

The cucurbitacins are a group of tetracyclic triterpenoids derived from the cucurbitane skeleton and found primarily in the Cucurbitaceae family. These triterpenoids, present in free or glycosidic form, are generally responsible for the bitter taste of the plants that contain them and are probably the principal cause of the antifeedant effects observed for such plants. Several plants used in traditional medicine to treat both inflammatory diseases as well as various types of tumors are rich in cucurbitacins, a fact which has given rise to several studies concerning their potential use as anti-inflammatory and anticancer agents. Nevertheless, since many cucurbitacins are extremely toxic, rel…

ChemInform Abstract: Photoinduced Functionalization of the C-20 Methyl Group of the Nor-diterpene Atractyligenin.

2010

Abstract Irradiation of the nor-diterpene atractyligenin at λ =254 nm in methanol gave, on one hand, the decarboxylation product, and provided, on the other hand, the transformation of the C-20 angular methyl into a methylene-carbomethoxy group. A photochemical pathway involving formation of C-19/C-20 bond is suggested.