63478-76-2Relevant academic research and scientific papers
Polydiacetylene stabilized gold nanoparticles - extraordinary high stability and integration into a nanoelectrode device
Liffmann,Homberger,Mennicken,Karth?user,Simon
, p. 102981 - 102992 (2015)
A new diacetylene containing photopolymerizable ligand molecule was developed, and tailored for applications in nanoelectronic devices based on gold nanoparticles. This ligand molecule consists of a thiol group, a diacetylene unit and a terminal carboxylic group. The thiol group guarantees preferred binding to the gold nanoparticles surface whereas at the same time the carboxylic group enables electrostatic stabilization. Applying this ligand molecule, gold nanoparticles in the size range of 12-13 nm were prepared. The diacetylene unit was polymerized upon UV irradiation leading to a polymeric ligand shell. Investigations including colloidal stability towards NaCl, DTT displacement reactions, and temperature were performed and indicate an extraordinary high degree of steric and electrostatic stabilization. Individual or at least a few of these particles were immobilized in between nanoelectrodes, thus forming nanoelectronic devices, which were characterized by transport measurements.
Intramolecular silicon-assisted cross-coupling reactions: General synthesis of medium-sized rings containing a 1,3-cis-cis diene unit
Denmark, Scott E.,Yang, Shyh-Ming
, p. 2102 - 2103 (2002)
The combination of ring-closing metathesis and Pd-catalyzed, silicon-assisted intramolecular cross-coupling has been developed to provide an effective and powerful method for construction of medium-sized rings with an internal 1,3-cis-cis diene unit. Allylic alcohols bearing a Z-iodoalkenyl tether can be silylated with chlorodimethylvinylsilane and subjected to Mo-catalyzed ring-closing metathesis to form unsaturated siloxanes. Activation of the siloxane with tetrabutylammonium fluoride in the presence of [allylPdCl]2 leads to high yielding ring-closing reactions to form 9-, 10-, 11- and 12-membered rings. Extension to the synthesis of 9-membered ring unsaturated ethers has also been accomplished. Noteworthy features of this process include: (1) a highly stereospecific intramolecular coupling process, (2) flexible positioning of the hydroxy group, and (3) potential extension to other medium-sized carbocycles and heterocycles. Copyright
Total synthesis of two novel brominated acetylenic diols (+)-diplyne C and E: Stereoselective construction of the (E)-1-bromo-1-alkene
Gung, Benjamin W.,Gibeau, Craig,Jones, Amanda
, p. 3107 - 3114 (2005)
The total syntheses of the enantiomers of two novel brominated polyacetylenic natural products diplynes C and E are reported. Pd and Cu(I)-catalyzed coupling reactions were employed to synthesize the diyne and enyne units. The stereochemistry of the terminal (E)-alkenyl bromide in diplyne C was constructed stereoselectively using Brown's hydroboration-bromination procedure. The stereochemistry of the internal (E)-double bond in diplyne E was established using a Takai reaction. The stereocenter was derived from d-mannitol.
On the intramolecular pyrone Diels-Alder approach to basiliolide B
Kozytska, Mariya V.,Dudley, Gregory B.
, p. 2899 - 2901 (2008)
A unified synthetic approach to the basiliolides/transtaganolides is outlined herein, along with studies illustrating the feasibility of the strategy with respect to the total synthesis of basiliolide B. This work lays the foundation for chemical synthesis of an emerging family of Thapsia metabolites.
Synthesis of brombyins II and III, cyclostachines A and B, and cyclopiperstachine, plant-derived octahydronaphthalenes
Lygo, Barry,Beaumont, Douglas J.,Cooke, Jason W.B.,Hirst, David J.
, p. 618 - 622 (2010)
In this paper we present a study into the direct formation of five plant-derived natural products via intramolecular Diels-Alder cycloaddition of a series of 1,7,9-decatriene precursors. Methods for the preparation of the trienes are also discussed. Georg Thieme Verlag Stuttgart · New York.
Directed Regioselective Carbometallation of 1,2-Dialkyl-Substituted Cyclopropenes
Cohen, Yair,Marek, Ilan
supporting information, p. 26368 - 26372 (2021/11/10)
A regio- and diastereoselective copper-catalyzed carbomagnesiation of 1,2-dialkylated cyclopropenes is reported. The regioselectivity is controlled by a subtle tethered Lewis basic moiety. The chelating moieties allow the differentiation between two electronically tantamount organometallic intermediates. Further functionalization grants access to polysubstituted stereodefined cyclopropanes bearing up to five alkyl groups.
Total Synthesis of a Mycolic Acid from Mycobacterium tuberculosis
Buter, Jeffrey,Fodran, Peter,Jayaraman, Dhineshkumar,Minnaard, Adriaan J.,Moody, D. Branch,Ocampo, Tonatiuh A.,Tahiri, Nabil,Van Rhijn, Ildiko,Witte, Martin D.
supporting information, p. 7555 - 7560 (2020/03/23)
In Mycobacterium tuberculosis, mycolic acids and their glycerol, glucose, and trehalose esters (“cord factor”) form the main part of the mycomembrane. Despite their first isolation almost a century ago, full stereochemical evaluation is lacking, as is a scalable synthesis required for accurate immunological, including vaccination, studies. Herein, we report an efficient, convergent, gram-scale synthesis of four stereo-isomers of a mycolic acid and its glucose ester. Binding to the antigen presenting protein CD1b and T cell activation studies are used to confirm the antigenicity of the synthetic material. The absolute stereochemistry of the syn-methoxy methyl moiety in natural material is evaluated by comparing its optical rotation with that of synthetic material.
Total Synthesis of the Tetrasubstituted Furan Fatty Acid Metabolite CeDFP via Au-Catalyzed Intermolecular Alkyne Hydroarylation
Wang, Yamin,Pritchard, Gareth J.,Kimber, Marc C.
supporting information, p. 4892 - 4895 (2019/06/27)
The first total synthesis of the tetrasubstituted furan fatty acid (FFA) metabolite 5-[(1E)-2-carboxyethenyl]-3,4-dimethyl-2-furanpentanoic acid (CeDFP) is reported. CeDFP is a FFA metabolite isolated from shark livers and is related to the known FFA metabolites CMPF and CMPentylF. Key elements of the synthetic route to CeDFP include an iodine-promoted 5-endo-dig cyclization of a 1,2-alkyne diol, a methyllithium-mediated insertion of the C3-methyl group, and a Au(I)-catalyzed intermolecular hydroarylation to introduce the unsaturated ester.
Enantioselective Rhodium-Catalyzed Dimerization of ω-Allenyl Carboxylic Acids: Straightforward Synthesis of C2-Symmetric Macrodiolides
Steib, Philip,Breit, Bernhard
supporting information, p. 6572 - 6576 (2018/05/08)
Herein, we report on the first enantioselective and atom-efficient catalytic one-step dimerization method to selectively transform ω-allenyl carboxylic acids into C2-symmetric 14- to 28-membered bismacrolactones (macrodiolides). This convenient asymmetric access serves as an attractive route towards multiple naturally occuring homodimeric macrocyclic scaffolds and demonstrates excellent efficiency to construct the complex, symmetric core structures. By utilizing a rhodium catalyst with a modified chiral cyclopentylidene-diop ligand, the desired diolides were obtained in good to high yields, high diastereoselectivity, and excellent enantioselectivity.
Synthesis and Evaluation of a Series of Bis(pentylpyridinium) Compounds as Antifungal Agents
Obando, Daniel,Koda, Yasuko,Pantarat, Namfon,Lev, Sophie,Zuo, Xiaoming,Bijosono Oei, Johanes,Widmer, Fred,Djordjevic, Julianne T.,Sorrell, Tania C.,Jolliffe, Katrina A.
, p. 1421 - 1436 (2018/07/29)
A series of bis(4-pentylpyridinium) compounds with a variety of spacers between the pyridinium headgroups was synthesised, and the antifungal activity of these compounds was investigated. Lengthening the alkyl spacer between the pentylpyridinium headgroups from 12 to 16 methylene units resulted in increased antifungal activity against C. neoformans and C. albicans, but also resulted in increased hemolytic activity and cytotoxicity against mammalian cells. However, inclusion of an ortho-substituted benzene ring in the centre of the alkyl spacer resulted in decreased cytotoxicity and hemolytic activity, while maintaining antifungal potency. Replacement of the alkyl and aromatic-containing spacers by more hydrophilic ethylene glycol groups resulted in a loss of antifungal activity. Some of the compounds inhibited fungal PLB1 activity, but the low correlation of this inhibition with antifungal potency indicates PLB1 inhibition is unlikely to be the predominant mode of antifungal action of this class of compounds, with preliminary studies suggesting they may act via disruption of fungal mitochondrial function.
