نتایج جستجو برای: intermediate β

تعداد نتایج: 306377  

Journal: :Organic & biomolecular chemistry 2014
Roderick W Bates Rab'iah Nisha Khanizeman Hajime Hirao Yu Shan Tay Patcharaporn Sae-Lao

The β-amino acid antibiotic (+)-negamycin has been synthesised in ten steps from epichlorohydrin via Sakurai allylation of an isoxazolidine intermediate. The key allylation reaction proceeded with complete trans-selectivity, which is attributed to electrostatic attraction between the chlorine atom and the iminium ion in the Sakurai intermediate.

Journal: :Angewandte Chemie 2012
Daniel T Cohen Chad C Eichman Eric M Phillips Emily R Zarefsky Karl A Scheidt

New DKR type: An N-heterocyclic carbene (NHC)-catalyzed dynamic kinetic resolution of racemic α-substituted β-keto esters has been developed. This method relies on the epimerization of an NHC-enol intermediate before subsequent aldol/acylation events. Highly substituted β-lactones are produced in good yield with good to excellent selectivities (see scheme).

Journal: :Chemical communications 2012
Manuel Iglesias María Pérez-Nicolás Pablo J Sanz Miguel Victor Polo Francisco J Fernández-Alvarez Jesús J Pérez-Torrente Luis A Oro

A synthon for a 14-electron Ir(III) species is described. The geometrical control exerted by the ligand system over the Ir-alkenyl intermediate in hydrosilylation of terminal alkynes precludes formation of the more thermodynamically stable β-(E)-vinylsilane, thus affording the β-(Z) isomer in excellent yields.

Journal: :Organic & biomolecular chemistry 2014
Erwan Le Gall Stéphane Sengmany Issa Samb Sabrina Benakrour Christopher Colin Antoine Pignon Eric Léonel

The multicomponent synthesis of α,β-disubstituted N-sulfonyl β-amino esters is described. It involves a zinc-mediated, cobalt-catalyzed three-component reaction between sulfonylimines, acrylates and organic bromides. A possible mechanism is proposed, emphasizing the intermediate formation of an organocobalt as the initiator of a Mannich-like process.

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2008

2015
Peter P. Ruvolo YiHua Qiu Kevin R. Coombes Nianxiang Zhang E. Shannon Neeley Vivian R. Ruvolo Numsen Hail Gautam Borthakur Marina Konopleva Michael Andreeff Steven M. Kornblau

BACKGROUND Acute myeloid leukemia (AML) patients with highly active AKT tend to do poorly. Cell cycle arrest and apoptosis are tightly regulated by AKT via phosphorylation of GSK3α and β isoforms which inactivates these kinases. In the current study we examine the prognostic role of AKT mediated GSK3 phosphorylation in AML. METHODS We analyzed GSK3α/β phosphorylation by reverse phase protein ...

Journal: :Angewandte Chemie 2022

The asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners far-less developed. We report herein the first examples of catalytic enantioselective tryptamines α-ketoamides. A new class easily accessible prolyl-urea organocatalysts bearing a single H-bond donor function catalyzes title to afford 1,1-disubstituted tetrahydro-...

Journal: :The Journal of urology 2013
Anthony Atala

Numerous proinflammatory cytokines have been implicated in the reorganization of lower urinary tract function following cyclophosphamide (CYP)-induced cystitis. The present study investigated the functional profile of three pleiotropic transforming growth factor-β (TGF-β) isoforms and receptor (TβR) variants in the normal and inflamed (CYP-induced cystitis) rat urinary bladder. Our findings ind...

2014
Liudmila Dzhekieva S. A. Adediran R. F. Pratt

Specific boronic acids are generally powerful tetrahedral intermediate/transition state analogue inhibitors of serine amidohydrolases. This group of enzymes includes bacterial β-lactamases and DD-peptidases where there has been considerable development of boronic acid inhibitors. This paper describes the synthesis, determination of the inhibitory activity, and analysis of the results from two α...

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