63478-76-2Relevant articles and documents
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.
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.
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.
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.
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.
