187324-64-7Relevant articles and documents
Asymmetric Total Synthesis of (?)-Dehydrocostus Lactone by Domino Metathesis
Barthel, André,H?fner, Franziska,Hennersdorf, Felix,J?ger, Anne,Kaden, Felix,Lorenz, Melanie,Metz, Peter,Nowotni, Susanne,Weigand, Jan J.
supporting information, p. 3579 - 3586 (2021/07/22)
An efficient total synthesis of the sesquiterpenoid (?)-dehydrocostus lactone is reported. Our earlier approach by a domino enediyne metathesis was extended by a domino dienyne metathesis strategy to give access to suitably functionalized hydroazulene cores. Highly stereoselective asymmetric anti aldol reactions provided the enantiopure substrates for this key step of our synthesis. Multiple hydroboration/oxidation of the resulting hydroazulenes set up three out of four stereogenic centers in a single step. First, oxidation to give a diketo-γ-lactone enabled an enantioselective formal synthesis of the target guaianolide. Subsequently, the final steps of this approach were improved by using a double carbonyl olefination at the stage of a masked γ-butyrolactone, which completed the synthesis in a much more efficient way.
Synthesis of a diastereomer of the marine macrolide lytophilippine A
Klüppel, André,Gille, Annika,Karayel, Ceren Ester,Hiersemann, Martin
supporting information, p. 2421 - 2425 (2019/03/29)
The synthesis of a diastereomer of lytophilippine A required 22 longest linear steps using known building blocks. Cross-metathesis/asymmetric aldol addition and regioselective esterification/ring-closing metathesis served as efficient combi tools for scaffold construction. Detailed NMR investigations in different solvent (systems) provide evidence for a deep-seated configurational misassignment of the molecule named lytophilippine A.
The synthesis and evaluation of a solution phase indexed combinatorial library of non-natural polyenes for reversal of p-glycoprotein mediated multidrug resistance
Andrus, Merritt B.,Turner, Timothy M.,Sauna, Zuben E.,Ambudkar, Suresh V.
, p. 4973 - 4983 (2007/10/03)
A combinatorial library of polyenes, based on (-)-stipiamide, has been constructed and evaluated for the discovery of new multidrug resistance reversal agents. A palladium coupling was used to react each individual vinyl iodide with a mixture of the seven acetylenes at near 1:1 stoichiometry. The coupling was also used to react each individual acetylene with the mixture of six vinyl iodides to create 13 pools indexed in two dimensions for a total of 42 compounds. Individual compounds were detected at equimolar concentration. The vinyl iodides, made initially using a crotylborane addition to generate the anti1,2-hydroxylmethyl products, were now made using a more efficient norephedrine propionate boron enolate aldol reaction. The indexed approach, ideally suited for cellular assays that involve membrane-bound targets, allowed for the rapid identification of reversal agents using assays with drug-resistant human breast cancer MCF7-adrR cells. Intersections of potent pools identified new compounds with promising activity. Aryl dimension pools showed R = ph and naphthyl as the most potent. The acetylene dimension had R' = phenylalaninol and alaninol as the most potent. Isolated individual compounds, both active and nonpotent, were assayed to confirm the library results. The most potent new compound was 4ek (R = naphthyl, R' = phenylaninol) at 1.45 μM. Other nonnatural individual naphthyl-amide compounds showed potent MDR reversal including the morpholino-amide 4ej (1.69 μM). Synergistic activities attributed to the two ends of the molecule were also identified. Direct interaction with Pgp was established by ATPase and photoaffinity displacement assays. The results indicate that both ends of the polyene reversal agent are involved in Pgp interaction and can be further modified for increased potency.