نتایج جستجو برای: aromatic substitution

تعداد نتایج: 97354  

2013
Hans-Adolf Arfmann Wolf-Rainer Abraham Klaus Kieslich

Various monoand disubstituted cinnamic acid derivatives and aromatic carboxylic acids with saturated side chains were incubated mainly with Bacillus, Candida, Hansenula, and Saccharo­ m yces strains. The cinnamic acids carrying a hydroxyand/or a methoxy group at the 3and/or 4-position of the benzene ring were decarboxylated with high yields. Most of the reactions were terminated within 24 to 48...

2013
Wafaa S. Hamama Mohamed A. Ismail Hanaa A. Al-Saman Hanafi H. Zoorob

The reaction of 6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione (1) as a binucleophile with primary aromatic or heterocyclic amines and formaldehyde or aromatic (heterocyclic) aldehydes in a molar ratio (1:1:2) gave the pyrimido[4,5-d]pyrimidin-2,4-dione ring systems 2-5. Treatment of 1 with diamines and formalin in molar ratio (2:1:4) gave the bis-pyrimido[4,5-d]pyrimidin-2,4-diones 6-8. Furth...

Journal: :Organic & biomolecular chemistry 2014
Christina T Lollar Katherine M Krenek Kevin J Bruemmer Alexander R Lippert

An exceptionally mild method for the preparation of isatin derivatives has been developed using a sulfur ylide mediated carbonyl homologation sequence starting from anthranilic acid precursors. This method proceeds at ambient temperature via a sulfur ylide intermediate without the need for protection of the amine or chromatographic isolation of the intermediate ylide. Gentle oxidation of the su...

Journal: :Molecules 2012
Jae-Chul Jung Yeonju Lee Jee-Young Son Eunyoung Lim Mankil Jung Seikwan Oh

Simple synthesis of modafinil derivatives and their biological activity are described. The key synthetic strategies involve substitution and coupling reactions. We determined the anti-inflammatory effects of modafinil derivatives in cultured BV2 cells by measuring the inhibition of nitrite production and expression of iNOS and COX-2 after LPS stimulation. It was found that for sulfide analogues...

2012

A typical coal tar pilch has been separated into fractions which have been analyzed and characterized by selected physical and chemical methods. These results have indicated the presence of molecules consisting of from one to several aromatic clusters, each having a mean cluster size near four aromatic rings. Information hau been obtained on aromaticity, hydrogen distribution and substitution i...

Journal: :Chemistry, an Asian journal 2011
Jinho Kim Youhwa Ohk Sae Hume Park Yousung Jung Sukbok Chang

The rhodium- or copper-catalyzed intramolecular aromatic carbenoid insertion of biaryldiazoacetates offers a convenient route to fluorene carboxylates with high yields. Whereas, thermal conditions provided a mixture of two regioisomeric products when substituted biaryldiazoacetates were employed as substrates. The developed catalytic conditions displayed an excellent level of regioselectivity, ...

2013
Magnus Liljenberg Tore Brinck Tobias Rein Mats Svensson

A computational approach using density functional theory to compute the energies of the possible σ-complex reaction intermediates, the "σ-complex approach", has been shown to be very useful in predicting regioselectivity, in electrophilic as well as nucleophilic aromatic substitution. In this article we give a short overview of the background for these investigations and the general requirement...

Journal: :Chemical communications 2015
Lanfang Zou Dawei Feng Tian-Fu Liu Ying-Pin Chen Stephen Fordham Shuai Yuan Jian Tian Hong-Cai Zhou

Stable porphyrin based porous polymer networks, PPN-23 and PPN-24, have been synthesized through a facile one-pot approach by the aromatic substitution reactions of pyrrole and aldehydes. PPN-24(Fe) shows high catalytic efficiency as a biomimetic catalyst in the oxidation reaction of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) in the presence of H2O2.

2013
Kalla Reddi Mohan Naidu Shaik Ibrahim Khalivulla Syed Rasheed Sharida Fakurazi Palanisamy Arulselvan Ola Lasekan Faridah Abas

Polymer supported dichlorophosphate (PEG-OPOCl(2)) is an efficient green catalyst for the electrophilic substitution reaction of indole with aromatic aldehydes, in neat condition, to afford an excellent yield of bis(indolyl) methanes with short reaction time, at room temperature. The synthesized compounds and their anti-cancer activity are evaluated.

Journal: :Chemical communications 2011
Elena del Puerto Santiago Sánchez-Cortés José V García-Ramos Concepción Domingo

A possibility of getting SERS spectra of insoluble aromatic compounds in colloidal silver solutions is described. The method tested for the organic pigment quinacridone quinone consists of dispersing it in calix[n]arenes. The potentials of such cavitands, both as dispersing and as silver functionalization agents, is reported as a function of the substitution in their lower rim and their cavity ...

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