نتایج جستجو برای: aryl group

تعداد نتایج: 992563  

2014
Imtiaz Khan Aliya Ibrar Shahid Hameed Jonathan M. White Jim Simpson

2-(4-Chloro-phen-yl)-2-oxoethyl 3-bromo-benzoate, C15H10BrClO3, was synthesized in a single-step reaction by condensation of 3-bromo-benzoic acid with 2-bromo-1-(4-chloro-phen-yl)ethanone in di-methyl-formamide in the presence of tri-ethyl-amine as a catalyst. The structure consists of an aryl ketone moiety linked to an aryl ester unit by a methyl-ene group. Both units are reasonably planar (r....

Journal: :Nature Synthesis 2022

Late-stage tritiation with high selectivity, isotopic purity and functional-group tolerance is important for the radiolabelling of drug candidates or bioactive compounds. Now, a broadly applicable protocol using aryl thianthrenium salts allows complex molecules by hydrogenolysis via an intermediate cationic palladium complex.

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1994
mehran chiaci ali mohajeri

conformational properties of n-aryl-1-azacyclooctan-5- ones with a p-methyl, m-methyl, and p-methoxy group as a substituent have been studied by 1h-nmr, 13c-nmr and ir spectroscopies. transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data of the respective monofun...

2004
Norihito Tokunaga Kazuhiro Yoshida Tamio Hayashi

Addition of lithium aryl(tetraisopropoxy)titanates [ArTi(OPri)4 Li ] to , -unsaturated ketones proceeded with high enantioselectivity (up to 99% ee) in the presence of an excess amount of chlorotrimethylsilane and a rhodium catalyst (3 mol % Rh), generated from [RhCl(C2H4)2]2 and (S)-binap, in tetrahydrofuran at 20°C to give high yields of the corresponding silyl enolates as 1,4-addition produc...

2012
Shimelis T. Hailu Ray J. Butcher Paul F. Hudrlik Anne M. Hudrlik

A ring-closing olefin metathesis reaction of tetra-kis-(all-yl-oxy)calix[4]arene gave the bis- calixarene, (15E,40E,60E)-65,74-bis-(prop-2-en-1-yl-oxy)-13,18,38,43,58,63-hexa-oxado-deca-cyclo-[28.26.8.7(20,36).1(11,45).1(51,55).0(5,57).0(7,12).0(19,24).0(26,64).0(32,37).0(44,49).1(68,72)]tetra-hepta-conta-1,3,5(57),7,9,11,15,19(24),20,22,26,28,30(64),32,34,36,40,44(49),45,47,51,53,55(65),60,68,...

Journal: :The journal of physical chemistry. A 2005
Markéta Bernatkova Hana Dvorakova Bruno Andrioletti Vladimír Kral Petr Bour

Eight meso-aryl calixphyrin derivatives were synthesized and their conformational equilibria and transitions studied with temperature-dependent NMR spectroscopy. On the basis of density functional computations, several conformer species could be identified and observed changes in chemical shifts explained. In some compounds, the aryl group rotation and porphyrin ring flipping could be monitored...

2013
Bernd Wrackmeyer Peter Thoma Wolfgang Milius

Two cyclic alkyl(aryl)boranes, a 1-bora-indane derivative 1, and a tricyclic derivative 4, containing the boron atom in a six-membered ring, were structurally characterized by NMR techniques in solution. The solid-state structure of the 1-bora-indane 1 was determined by X-ray crystallography. The reactivity of these cyclic alkyl(aryl)boranes towards monoalkynyltin compounds, Me3Sn–C≡C–Me and Me...

Journal: :Organic & biomolecular chemistry 2004
Alvise Perosa Pietro Tundo Maurizio Selva Sergei Zinovyev Alberto Testa

The rate of the Pd/C catalyzed Heck coupling of Ar-I with CH(2)=CH-R is accelerated tenfold by the presence of Aliquat 336 (A336), a well known phase transfer catalyst, and an ionic liquid. Both when conducted in A336 as solvent, and in an isooctane/A336/aqueous triphasic mixture, the Heck reaction of aryl iodides with electron deficient olefins, catalyzed by Pd/C, proceeds with high yields and...

Journal: :Science 2014
Zhiwei Zuo Derek T Ahneman Lingling Chu Jack A Terrett Abigail G Doyle David W C MacMillan

Over the past 40 years, transition metal catalysis has enabled bond formation between aryl and olefinic (sp(2)) carbons in a selective and predictable manner with high functional group tolerance. Couplings involving alkyl (sp(3)) carbons have proven more challenging. Here, we demonstrate that the synergistic combination of photoredox catalysis and nickel catalysis provides an alternative cross-...

Journal: :The Journal of organic chemistry 2010
Jean-Yves Balandier Marcos Chas Paul I Dron Sébastien Goeb David Canevet Ahmed Belyasmine Magali Allain Marc Sallé

A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, r...

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