Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

ISBN-13: 9783709192276 / Angielski / Miękka / 2012 / 243 str.

C. a. a. Van Bockl; A. -M Eklund; M. Petitou

Opis

The structure of eunicillin (89), a carbobicyclic diterpenoid isolated from the Mediterranean gorgonian Eunicella stricta, was reported in 1968 (1). At that time chlorine-containing diterpenoids had been dis- covered in the gorgonian Briareum asbestinum (2, 3), but it was not until 1977 that the structure of the first briaran, briarein A (211), was resolved by X-ray analysis (4). The first trinervitane diterpenoid (26), which was isolated from Trinervitermes termites, was reported in 1976 (5). OAc OAc ACO'**** OH 0 89 211 26 The discovery of these compounds marked the appearance of a large and growing group of diterpenoids which are commonly viewed as being formed from cembrane precursors by secondary carbon-carbon bond closures. It should be emphasized, however, that in the absence of biosynthetic evidence the question of which groups of diterpenoids that should be classified as cyclized cembranoids remains ambiguous. In the present article we have included five tobacco diterpenoids (1-5) which. possess prerequisite structural features and co occur with appropriate cembrane precursors in tobacco. Although structurally reminiscent of cyclized cembranoids, verticillanes, taxanes and cleomeolide are not dealt with, since these diterpenoids of plant origin are not believed to arise via preformed cembranoids (6-11).

Spis treści

Cyclized Cembranoids of Natural Occurrence.- I. Introduction.- A. Nomenclature and Structural Representation.- II. Cyclized Cembranoids from Tobacco.- III. Cyclized Cembranoids from Insects.- A. Nasutitermitinae.- 1. Bulbitermes Species.- 2. Cortaritermes Species.- 3. Grallatotermes Species.- 4. Hospitalitermes Species.- 5. Longipeditermes Species.- 6. Nasutitermes Species.- 7. Subilitermes Species.- 8. Trinervitermes Species.- 9. Velocitermes Species.- IV. Cyclized Cembranoids from Marine Invertebrates.- A. Gorgonacea.- 1. Astrogorgia, Calicogorgia, Euniceila and Muricella Species.- 2. Briareum Species.- 3. Erythropodium Species.- 4. Junceella and Plexaureides Species.- B. Alcyonacea.- 1. Alcyonium Species.- 2. Cespitularia Species.- 3. Cladiella, Litophyton, Sclerophytum and Sinularia Species.- 4. Gersemia Species.- 5. Minabea Species.- 6. Sarcophyton Species.- C. Stolonifera.- D. Pennatulacea.- 1. Cavernulina, Pteroides, Ptilosarcus, Renilla, Scytalium and Stylatula Species.- 2. Veretillum Species.- Addendum.- Acknowledgements.- References.- Chemical Synthesis of Heparin Fragments and Analogues..- 1. Introduction.- 1.1 Heparin.- 1.2 Heparin Fragments.- 2. Synthesis of the Antithrombin Binding Site.- 2.1 Strategy.- 2.2 Preparation of D-Glucuronic Acid Derivatives.- 2.3 Preparation of L-Iduronic Acid Derivatives.- 2.4 Synthesis of the Fully Protected Pentasaccharides.- 2.5 Synthesis of Building Blocks from Natural Disaccharides.- 2.5.1 Synthesis from Cellobiose.- 2.5.2 Synthesis from Maltose.- 2.6 Deprotection and Functionalisation.- 2.7 Recent Results in the Synthesis of the Antithrombin Binding Site.- 2.7.1 Synthesis of the ?-Methyl Glycoside of the Antithrombin Binding Site.- 2.7.2 Synthesis of the N-Acetylated Antithrombin Binding Sequence.- 3. Synthesis and Biological Properties of Analogues of the Antithrombin Binding Site.- 3.1 Analogues lacking N, O-Sulphate Groups at Defined Positions.- 3.2 Analogues with Modifications of the Carboxylate Groups at Defined Positions.- 3.3 A Potent Analogue with Extra 3-O-Sulphate Group at Unit H.- 3.4 Analogues of the Extra Sulphated, Potent Analogue (81).- 3.5 Analogues Containing “Opened” Uronic Acid Moieties.- 3.6 Analogues with Various Modifications.- 3.7 Alkylated Analogues of Heparin Pentasaccharides.- 4. Conformational Properties.- 5. Interaction of Heparin Pentasaccharide Fragments with Antithrombin III.- Acknowledgements.- References.- Author Index.- General Index Vol. 21–60.