نتایج جستجو برای: intramolecular cyclization

تعداد نتایج: 18338  

A new and imaginative technique for the synthesis of substituted pyranoquinoline via Algar Flyn Oyamanda oxidation cyclization approach has been achieved by hydrogen peroxide and sodium hydroxide catalyzed of quinoline chalcone with intramolecular cyclization to formed pyranoquinoline. In this reaction, two new C-C bonds were formed in a one step with high atom economy. The possible reaction pa...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1994
sasanin karimi k. grohamann l. todaro

results of the bromination and dehydrobromination of several angular methylated decalindiones are described. the key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

Journal: :Chemical communications 2013
Azusa Kondoh Kenichi Ando Masahiro Terada

Intramolecular cyclization of nitrogen-tethered alkynyl esters catalyzed by phosphazene organosuperbases P2-tBu and P4-tBu was investigated. Both acyclic and cyclic substrates underwent 5-exo-dig and 5-endo-dig cyclization. This reaction is a rare example of the intramolecular addition of enolates of simple esters to alkynes.

2013
Tristram Chivers Masood Parvez Peter Zoricak

Crystal Structure, 1,2,4-Thiadiazole, Intramolecular Cyclization The title compound was obtained in 82% yield by the intramolecular cyclization of 4BrC6H4C(NSCCl3)[N(SiMe3)2] in CH2CI2 at 23°C. It crystallizes in the triclinic system, space group PI, a = 7.957(3) Ä, b = 10.864(5) A, c = 5.625(1) A, a = 95.94(3)°, ß = 97.79(2)°, 7 = 100.72(3)°, V = 469.2(3) A3, and Z 2. The bond lengths of the p...

Journal: :Organic & biomolecular chemistry 2009
Paolo Ronchi Stefano Vignando Sara Guglieri Laura Polito Luigi Lay

An approach to the synthesis of pseudo-oligosaccharides based on the cross-metathesis reaction between distinct sugar-olefins, followed by intramolecular cyclization of the obtained heterodimer, is presented. In particular, the relative efficiency of two alternative approaches, the straightforward cross-metathesis reaction and the two-step procedure (self-metathesis followed by cross-metathesis...

Journal: :Organic Letters 2021

Straightforward access to [1,2]-annulated indoles, key substructures in natural products, is highly desirable yet challenging. Herein, a radical triggered fragmentary cyclization cascade reaction of ene-ynamides presented, providing rapid into indoles by an intermolecular addition, intramolecular cyclization, desulfonylative aryl migration, and site-selective C(sp2)-N sequence. DFT calculations...

Journal: :The Journal of organic chemistry 2008
Hitoshi Harada Reema K Thalji Robert G Bergman Jonathan A Ellman

Highly enantioselective catalytic intramolecular ortho-alkylation of aromatic imines containing alkenyl groups tethered at the meta position relative to the imine directing group has been achieved using [RhCl(coe)2]2 and chiral phosphoramidite ligands. Cyclization of substrates containing 1,1- and 1,2-disubstituted as well as trisubstituted alkenes were achieved with enantioselectivities >90% e...

A. Ghoorchian M. H. Ghorbani R. Fazaeli

Using a time-dependent-density functional theory (TD-DFT), Configuration Interaction Singles (CIS) and Zerner’s Intermediate Neglect of Differential Overlap (ZINDO) methods, we have investigated the UV-Visible spectra of one new intramolecular cyclization at before and after intramolecular attack. All structures were optimized at the B3LYP/6-311++G** level while UV-Visible parameters were calcul...

Journal: :Journal of Synthetic Organic Chemistry, Japan 1990

Journal: :journal of physical & theoretical chemistry 2012
m. h. ghorbani r. fazaeli a. ghoorchian

using a time-dependent-density functional theory (td-dft), configuration interaction singles (cis) and zerner’s intermediate neglect of differential overlap (zindo) methods, we have investigated the uv-visible spectra of one new intramolecular cyclization at before and after intramolecular attack. all structures were optimized at the b3lyp/6-311++g** level while uv-visible parameters were calcul...

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