457-45-4Relevant articles and documents
Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H2 Cleavage
Chirik, Paul J.,Shevlin, Michael,Zhong, Hongyu
supporting information, (2020/03/13)
The asymmetric hydrogenation of α,β-unsaturated carboxylic acids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri-, and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylic acids including Naproxen, (S)-Flurbiprofen, and a d-DOPA precursor. Turnover numbers of up to 200 were routinely obtained. Compatibility with common organic functional groups was observed with the reduced cobalt(0) precatalysts, and protic solvents such as methanol and isopropanol were identified as optimal. A series of bis(phosphine) cobalt(II) bis(pivalate) complexes, which bear structural similarity to state-of-the-art ruthenium(II) catalysts, were synthesized, characterized, and proved catalytically competent. X-band EPR experiments revealed bis(phosphine)cobalt(II) bis(carboxylate)s were generated in catalytic reactions and were identified as catalyst resting states. Isolation and characterization of a cobalt(II)-substrate complex from a stoichiometric reaction suggests that alkene insertion into the cobalt hydride occurred in the presence of free carboxylic acid, producing the same alkane enantiomer as that from the catalytic reaction. Deuterium labeling studies established homolytic H2 (or D2) activation by Co(0) and cis addition of H2 (or D2) across alkene double bonds, reminiscent of rhodium(I) catalysts but distinct from ruthenium(II) and nickel(II) carboxylates that operate by heterolytic H2 cleavage pathways.
Organomediated Enantioselective 18F Fluorination for PET Applications
Buckingham, Faye,Kirjavainen, Anna K.,Forsback, Sarita,Krzyczmonik, Anna,Keller, Thomas,Newington, Ian M.,Glaser, Matthias,Luthra, Sajinder K.,Solin, Olof,Gouverneur, Véronique
supporting information, p. 13366 - 13369 (2015/11/09)
The first organomediated asymmetric 18F fluorination has been accomplished using a chiral imidazolidinone and [18F]N-fluorobenzenesulfonimide. The method provides access to enantioenriched 18F-labeled α-fluoroaldehydes (>90 % ee), which are versatile chiral 18F synthons for the synthesis of radiotracers. The utility of this process is demonstrated with the synthesis of the PET (positron emission tomography) tracer (2S,4S)-4-[18F]fluoroglutamic acid.
COMPOUNDS THAT MODULATE INTRACELLULAR CALCIUM
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Page/Page column 127, (2011/04/18)
Described herein are compounds and pharmaceutical compositions containing such compounds, which modulate the activity of store-operated calcium (SOC) channels. Also described herein are methods of using such SOC channel modulators, alone and in combinatio
