Results 111 to 120 of about 47,136 (264)

Crystal structures of bis[4-(dimethylamino)pyridinium] tetrakis(thiocyanato-κN)manganate(II) and tris[4-(dimethylamino)pyridinium] pentakis(thiocyanato-κN)manganate(II)

open access: yesActa Crystallographica Section E: Crystallographic Communications, 2018
The crystal structures of the title salts, (C7H11N2)2[Mn(NCS)4] (1) and (C7H11N2)3[Mn(NCS)5] (2), consist of manganese(II) cations that are tetrahedrally (1) or trigonal–bipyramidally (2) coordinated to four or five terminal N-bonded thiocyanate ligands,
Tristan Neumann   +2 more
doaj   +1 more source

Precision Chemistry for Protein Lysine Modification

open access: yesChemistry – A European Journal, EarlyView.
Selective modification of lysine residues is challenging due to their similar intrinsic reactivity. Inspired by enzymatic recognition, ligand‐guided electrophiles enable site‐selective labeling and functionalization, while ligand‐guided catalyses achieve regioselective installation of bio‐relevant post‐translational modifications.
Mayu Onoda, Motomu Kanai
wiley   +1 more source

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

open access: yesBeilstein Journal of Organic Chemistry
Efficient water-solubilization of nanocarbons is desirable for both their biological and material applications, but so far has mainly relied on covalent modifications or amphiphiles featuring ionic side-chains. Here, we report a facile 2–4-step synthesis
Lorenzo Catti   +2 more
doaj   +1 more source

FLP Mediated Conversion of Difluorobenzylalkynes to Fluoroallenyl Oniums via an SN1’ Pathway

open access: yesChemistry – A European Journal, EarlyView.
Frustrated Lewis pair (FLP) selective C‒F activation of difluorobenzylalkynes allows the formation of fluoroallenic oniums via an SN1’ substitution pathway. The fluoroallenic onium salts are synthetic precursors that allow subsequent functionalization at allenic and onium positions.
Max Coles   +6 more
wiley   +1 more source

Investigating the chemistry of pyridinium ylides [PDF]

open access: yes, 2018
This thesis describes investigation into catalytic formation of pyridinium ylides from diazo compounds and their subsequent reactivity. In particular, cycloaddition reactions with electrophilic alkenes are performed to generate tetrahydroindolizines that
Abdullah, Rasha Azzam
core  

Oxidation of alcohols with pyridinium bromochromate

open access: yesCommunications, Faculty Of Science, University of Ankara Series B Chemistry and Chemical Engineering, 1996
Pyridinium bromochromate (PBC) is a versatile and inexpensive oxidizing agent. It converts different classes of alcohols to the corresponding carbonyl compounds. Primary and secondary benzylic alcohols are oxidized in moderate to high yields. Synthetic utility of the reagent has been shown to increase in the presence of glacial acetic acid for the ...
openaire   +2 more sources

Stereoretentive Nucleophilic Aromatic Substitution Accesses Atropisomeric 4‐Amino‐N‐Arylquinolinium Salts

open access: yesChemistry – A European Journal, EarlyView.
Quinolin‐4‐ones were converted to chloroquinolinium salts, allowing formation of axially chiral aminoquinolinium salts via an enantioretentive SNAr reaction with a variety of amine nucleophiles. The salts have a high rotational barrier, with a racemization half‐life of ∼1000s of years.
Darren Holmes   +5 more
wiley   +1 more source

Nitrooxylation in Organic Synthesis: From Classical Nitrate Ester Formation to Modern Catalytic Strategies

open access: yesChemistry – A European Journal, EarlyView.
Nitrooxylation—the installation of nitrate esters (–ONO2) has evolved from classical mixed‐acid protocols to catalytic and mechano‐, flow‐, photo‐, and electrochemical strategies. This review delineates ionic and radical manifolds for C–ONO2 bond formation, emphasizing mechanistic control, selected substrate scope, and selectivity.
Jayanta Dey, Dmitry Katayev
wiley   +1 more source

Ionic Hydrogenation of Pyridinium and Azetidinium Cations

open access: yes, 2017
Research described herein seeks to study the reactivity of CpRu(P-P)H with pyridinium and azetidinium cations. For the former, we wish to determine if a previously established methodology for the regioselective reduction of a particular pyridinium ...
Yang, Zheren Jim
core   +2 more sources

Detection of Testosterone Esters in Urine: Evidence of Trace‐Level Detectability in Doping Control Samples

open access: yesDrug Testing and Analysis, EarlyView.
An ultrasensitive LC‐MS/MS method for detecting testosterone esters (T‐esters) in urine at sub–pg/mL levels is presented. This approach, employing Girard P derivatization, provides the first evidence of T‐esters' trace‐level detectability in human urine.
Daniel Pecher   +3 more
wiley   +1 more source

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