نتایج جستجو برای: tetrasubstituted imidazoles

تعداد نتایج: 4152  

Journal: :Organic & biomolecular chemistry 2014
Chun-Ru Cao Song Ou Min Jiang Jin-Tao Liu

A series of tetrasubstituted fluoroalkene derivatives were synthesized by the reaction of α-fluoro-β-carbonyl benzothiazol-2-yl sulfones with various nucleophiles in good yields with high stereoselectivities. The predominant cis configuration of fluorine and alkynyl groups was observed. A single isomer was obtained when a ketone, acetate or amide was used as the substrate in the presence of a b...

Journal: :Chemistry 2003
Shengming Ma Ning Jiao Longwu Ye

The Pd(0)-catalyzed regio- and stereoselective addition of organoboronic acids to allenes leads to stereodefined tri- or tetrasubstituted alkenes. Furthermore, this method shows high substitutent-loading capability and tolerance of various substitutents. A hydropalladation-Suzuki coupling mechanism, which may account for the regio- and stereoselectivity, is proposed.

Journal: :Journal of the American Chemical Society 2013
Marcos G Suero Elliott D Bayle Beatrice S L Collins Matthew J Gaunt

Copper catalysts enable the electrophilic carbofunctionalization of alkynes with vinyl- and diaryliodonium triflates. The new process forms highly substituted alkenyl triflates from a range of alkynes via a pathway that is opposite to classical carbometalation. The alkenyl triflate products can be elaborated through cross-coupling reactions to generate synthetically useful tetrasubstituted alke...

Journal: :Organic letters 2003
Utpal Majumder Jason M Cox Jon D Rainier

[structure: see text] This manuscript describes our synthesis of the F-H subunit of gambierol. In addition to the synthesis of the tricycle, of note is an interesting protecting group influence on the generation of a C(23) C-glycoside as well as the use of ring-closing metathesis to generate a tetrasubstituted enol ether.

2017
Lei Yang Romain Melot Markus Neuburger Olivier Baudoin

The first efficient palladium(0)-catalyzed enantioselective C(sp)–H activation reaction using a catalytic chiral base and an achiral phosphine ligand is reported. Fine-tuning the binol-derived phosphoric acid pre-catalyst and the reaction conditions was found to be crucial to achieve high levels of enantioselectivity for a variety of indoline products containing both triand tetrasubstituted ste...

Journal: :Angewandte Chemie 2012
Feng Li Alvaro Muñoz-Castro Slavi C Sevov

Reaching neutral territory: The title compound, the first tetrasubstituted deltahedral Zintl cluster, is no longer an ion (see picture; Ge green, Si purple, Sn blue). It is a neutral molecule formed by a reaction of the trisilylated anion with Ph(3) SnCl.

Journal: :Antimicrobial agents and chemotherapy 2003
Eric R Dabbs Samantha Naidoo Catherine Lephoto Natalya Nikitina

Rhodococcus equi and species of Nocardia and Gordonia may be human opportunistic pathogens. We find that these, as well as several isolates from closely related genera, are highly susceptible to the imidazoles bifonazole, clotrimazole, econazole, and miconazole, whose MICs are </=1 micro g/ml. In liquid cultures 1 micro g of the drug/ml was bacteriostatic and 10 micro g/ml was bactericidal. On ...

Journal: :Ultrasonics sonochemistry 2013
Javad Safari Zohre Zarnegar

Fe(3)O(4) nanoparticles were prepared by chemical coprecipitation method and subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction. Grafting of chlorosulfuric acid on the amino-functionalized Fe(3)O(4) nanoparticles afforded sulfamic acid-functionalized magnetic nanoparticles (SA-MNPs). SA-MNPs was found to be a mild and effective solid acid catalyst for the ef...

Journal: :Acta poloniae pharmaceutica 2011
Asif Husain Nadeem Siddiqui Md Sarafroz Yasmin Khatoon Mohd Rasid Niyaz Ahmad

A series of 1,2,4-trisubstituted-1H- imidazole derivatives (4a-o) was synthesized by reacting 2,4-disubstituted-1H-imidazoles (3a-o) with chlorobenzene in the presence of triethylamine. Phenylglyoxal (2) was reacted with different aromatic aldehydes in the presence of ammonium acetate and glacial acetic acid to afford the disubstituted imidazoles (3a-o). The structures of the synthesized compou...

Journal: :Molecules 2005
Konstantin V Kudryavtsev Veronika V Irkha

Tetrasubstituted pyrrolidines representing analogs of homoproline were synthesized by three-component condensation of aryl(heteroaryl)aldehydes, asparagine and N-methylmaleimide (NMM). Compounds with (1S*, 3R*, 3aS*, 6aR*)-configuration at the corresponding carbon positions of the bicyclic pyrrolidine ring could be isolated ona preparative scale.

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