612090-71-8Relevant academic research and scientific papers
Total synthesis of (-)-zampanolide and structure-activity relationship studies on (-)-dactylolide derivatives
Zurwerra, Didier,Glaus, Florian,Betschart, Leo,Schuster, Julia,Gertsch, Jürg,Ganci, Walter,Altmann, Karl-Heinz
supporting information, p. 16868 - 16883 (2013/03/14)
A new total synthesis of the marine macrolide (-)-zampanolide (1) and the structurally and stereochemically related non-natural levorotatory enantiomer of (+)-dactylolide (2), that is, ent-2, has been developed. The synthesis features a high-yielding, selective intramolecular Horner-Wadsworth-Emmons (HWE) reaction to close the 20-membered macrolactone ring of 1 and ent-2. The β-keto phosphonate/aldehyde precursor for the ring-closure reaction was obtained by esterification of a ω-diethylphosphono carboxylic acid fragment and a secondary alcohol fragment incorporating the THP ring that is embedded in the macrocyclic core structure of 1 and ent-2. THP ring formation was accomplished through a segment coupling Prins-type cyclization. Employing the same overall strategy, 13-desmethylene-ent-2 as well as the monocyclic desTHP derivatives of 1 and ent-2 were prepared. Synthetic 1 inhibited human cancer cell growth in vitro with nM IC50 values, while ent-2, which lacks the diene-containing hemiaminal-linked side chain of 1, is 25- to 260-fold less active. 13-Desmethylene-ent-2 as well as the reduced versions of ent-2 and 13-desmethylene-ent-2 all showed similar cellular activity as ent-2 itself. The same activity level was attained by the monocyclic desTHP derivative of 1. Oxidation of the aldehyde functionality of ent-2 gave a carboxylic acid that was converted into the corresponding N-hexyl amide. The latter showed only μM antiproliferative activity, thus being several hundred-fold less potent than 1. It's the side chain that matters: The marine macrolide (-)-zampanolide (1) has been synthesized via (-)-dactylolide (ent-2), the non-natural enantiomer of the marine natural product (+)-dactylolide (2), employing a high-yielding intramolecular Horner-Wadsworth-Emmons reaction to close the macrolactone ring. While the hemiaminal-linked side chain in 1 is crucial for nanomolar antiproliferative activity, the methylene group and the aldehyde functionality in ent-2 are dispensable. A monocyclic destetrahydropyran derivative of 1 shows equal activity as ent-2. Copyright
Synthesis of (-)-dactylolide and 13-desmethylene-(-)-dactylolide and their effects on tubulin
Zurwerra, Didier,Gertsch, Juerg,Altmann, Karl-Heinz
supporting information; experimental part, p. 2302 - 2305 (2010/08/05)
An efficient new synthesis has been elaborated for non-natural (-)-dactylolide ((-)-2) and its 13-desmethylene analogue 4, employing a HWE-based macrocyclization approach with β-keto-phosphonate/aldehyde 19 and the respective 13-desmethylene derivative as the key intermediates. Both (-)-2 and 4 as well as the corresponding C20 alcohols inhibit human cancer cell proliferation with IC50 values in the sub-micromolar range and induce the polymerization of tubulin in vitro.
Diastereoselective palladium-catalyzed formate reduction of allylic carbonates en route to polypropionate systems
Chau, Anh,Paquin, Jean-Francois,Lautens, Mark
, p. 1924 - 1933 (2007/10/03)
Diastereoselective palladium-catalyzed formate reduction of allylic carbonates presents unique opportunities for applications in target-oriented organic synthesis provided that selectivity, in particular stereoselectivity, in the course of this metal-cata
Diastereoselective Palladium-Catalyzed Formate Reduction of Allylic Carbonates as a New Entry into Propionate Units
Lautens, Mark,Paquin, Jean-Francois
, p. 3391 - 3394 (2007/10/03)
(Equation presented) The diastereoselective palladium-catalyzed formate reduction of allylic carbonates is described. Reduction of allylic carbonates under mild conditions (Pd(OAc)2 (2.5-5 mol %), [n-Bu 3PH]BF4 (2.5-5 mol
