نتایج جستجو برای: alternative substituents
تعداد نتایج: 311992 فیلتر نتایج به سال:
A large set of more than 3 million molecules was processed to find all the organic substituents contained in the set and to identify the most common ones. During the analysis, 849 574 unique substituents were found. Extrapolated to the number of known organic molecules, this result suggests that about 3.1 million substituents are known. Based on these findings the size of virtual organic chemis...
Some alkyl and aryl derivatives of 9H-purine-6-thiol were synthesized and evaluated in vitro and in vivo for potential antithyroid effects. Spectrophotometric studies demonstrated 1:1 charge transfer complexation between iodine and these compounds with quite high values of the formation constants. The blood assays of rats treated with these compounds revealed significant antithyroid activity fo...
The unexpected ability of arylzinc reagents bearing electron-donating substituents to react in a Friedel-Crafts fashion (cine) with electrophiles like perpivaloylated glucoside bromide and benzhydryl bromides in competition with organometallic coupling (ipso) is shown. The stereoelectronic factors required to promote the cine reactivity versus the classical ipso, and the mechanism of this alter...
The direct C-H annulation of anilines or related compounds with internal alkynes provides straightforward access to 2,3-disubstituted indole products. However, this transformation proceeds with poor regioselectivity in the synthesis of unsymmetrically 2,3-diaryl substituted indoles. Herein, we report the rhodium(III)-catalyzed C-H annulation of nitrones with symmetrical diaryl alkynes as an alt...
This study reports a facile method for the synthesis of a variety of 5and 6-substituted tryptophan derivatives that are difficult to prepare using alternative enzymatic approaches. Acylation of an activated amino acid, derived from serine in situ, is coupled with an enzymatic resolution step to furnish enantiopure analogues bearing a range of electron withdrawing and releasing substituents. Iso...
The living cationic ring-opening polymerization of 2-oxazolines with fluorinated aromatic substituents was found to be strongly accelerated by o-fluoro substituents.
1-Carboxymethyl-3-methylimidazolium chloride {[cmmim]Cl} is utilized as a highly efficient and reusable catalyst for the synthesis of bis(indolyl)methanes by the condensation reaction of indole with arylaldehydes under solvent-free conditions at room temperature. In summary, the presented method have several advantages including simplicity, low cost, generality, efficiency, clean reaction profi...
The epoxidation of olefins with tetra n-butylammonium periodate, n-Bu4/NIO4, is catalyzed by six different tetrakis (4-substituted phenyl) porphyrinatomanganese(III) acetate, Mn(T4-XPP)OAc, Complexes in the presence of imidazole as an axial ligand with low to high yields and complete selectivity at room temperature. While the electronic effects of the highly electron-w...
A regioselective vinylation of aromatic and aliphatic aldehydes promoted by the merging photoredox nickel catalysis is here reported. comprehensive investigation on reaction conditions allowed disclosure a valid reproducible protocol based nickel-mediated reductive coupling approach under visible light irradiation. The employment 3CzClIPN (2,4,6-tris(carbazol-9-yl)-5-chloro-isophthalonitrile) a...
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