نتایج جستجو برای: trityl carbocation

تعداد نتایج: 615  

Journal: :Angewandte Chemie 2023

Different electronic effects in the starting anthracene-containing polyphenylene substrate (bottom) afford two different nanographenes under Scholl reaction conditions, namely spironanographenes (R=H) on left and a helically arranged molecular nanographene having orthogonal aromatic moieties linked by an octafluoroanthracene core (R=F) right. The stabilities of intermediate trityl cations conco...

Journal: :Chemical communications 2016
Andreas Uwe Meyer Anna Lucia Berger Burkhard König

We report a one-step procedure for the preparation of N-(2-pyrrole)-sulfonamides from sulfonamides and pyrroles. The reaction uses visible light, an acridinium dye as photocatalyst and oxygen as the terminal oxidant for the oxidative C-N bond formation; structures of several reaction products were confirmed by X-ray structure analysis. The reaction is selective for pyrroles, due to the availabl...

Journal: :Archives of pharmacal research 2003
Young Hoon Jung Ji Duck Kim

We examined the effect of p-substituents in p-substituted cinnamyl methyl ethers and 1-(p-substituted phenyl)allyl methyl ethers with CSI, and confirmed that the CSI reaction of allyl ethers (p-substituted ethers) is a competitive reaction of S(N)i and S(N)1 mechanism according to the stability of the carbocation. And, the only terminal allylic amine was obtained through the migration reaction ...

Journal: :Free Radical Biology and Medicine 2009

Journal: :Physical chemistry chemical physics : PCCP 2013
Lloyd Lumata Matthew E Merritt Zoltan Kovacs

Replacement of protons by deuterons in the glassing solvents led to 2-3-fold improvement of the (13)C dynamic nuclear polarization (DNP) solid-state NMR signal for samples doped with large electron spin resonance (ESR) linewidth free radicals galvinoxyl, DPPH, and 4-oxo-TEMPO. Meanwhile, the reverse effect is observed for (13)C DNP using small ESR linewidth free radicals BDPA and trityl OX063.

2014
Zeynep Gültekin Mehmet Civan Wolfgang Frey Tuncer Hökelek

The asymmetric unit of the title compound, C26H28O6·2CH3OH, contains two independent methyl 6-O-trityl-α-d-gluco-pyran-oside mol-ecules and four methanol solvent mol-ecules. The rings of two methyl α-d-gluco-pyran-oside adopt chair conformations. In the crystal, extensive intra- and inter-molecular O-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional supra-molecular archi...

2003
J. Taylor-Papadimitriou C. Sakarellos P. Mazarakis

A new method for the preparation of S-trityl(i.e. triphenylmethyl) and S-diphenylmethyl-cysteines or -cysteine peptides involves treatment of cysteine or cysteine peptides with aralkylcarbinols in the presence of trifluoroacetic acid or hydrogen halides in acetic acid solution. The optimal conditions for the removal of these S-protecting aralkyl groups by trifluoroacetic acid or hydrogen halide...

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