Now showing items 31-40 of 1859
(Science Museum, Londres, 2016)
(Science Museum, Londres, 2011)
Gas-phase synthesis of hydroxyacetophenones by acylation of phenol with acetic acid
(Elsevier Science, 2004-09)
The gas-phase synthesis of aromatic ketones via acylation of phenol with acetic acid was studied on SiO2–Al2O3, Al-MCM-41, zeolites HY and ZSM5, and tungstophosphoric acid (HPA) supported on MCM-41 and carbon. At contact ...
Understanding the influence of Lewis acids in the regioselectivity of the Diels–Alder reactions of 2-methoxy-5-methyl-1,4-benzoquinone: A DFT study
(Elsevier B.V., 2009-03-03)
The mechanisms of the Diels–Alder (DA) reactions of 2-methoxy-5-methyl-1,4-benzoquinone 1 with 2- methyl-1,3-butadiene 2, in the absence and in the presence of LA catalysts, have been studied using the DFT method at the ...
Synthesis of acyl-hydrazone from usnic acid and isoniazid and its anti-Mycobacterium tuberculosis activity
(Universidad Nacional de Colombia, 2017)
Compound usnic acid (1), isolated from lichen Evernia prunastri (Cajamarca-Peru) and the synthesis and characterization of its acyl-hydrazone (2), from the condensation reaction between usnic acid and isoniazid in an ethanol ...
Preparation of bifunctional mesoporous silica nanoparticles by orthogonal click reactions and their application in cooperative catalysis
(Wiley-VCH VerlagWeinheim, 2012-12)
The synthesis of bifunctional mesoporous silica nanoparticles is described. Two chemically orthogonal functionalities are incorporated into mesoporous silica by co-condensation of tetraethoxysilane with two orthogonally ...
Formation of substituted N-oxide hydroxyquinolines from o-nitrophenyl Baylis-Hillman adduct: a new key intermediate intercepted by ESI-(+)-MS(/MS) monitoring
(Pergamon-elsevier Science LtdOxfordInglaterra, 2006)
Rebound acid hypersecretion after withdrawal of gastric acid suppressing drugs: new evidence of similitude
(ELSEVIER SCI LTD, 2011)
Background: Homeopathy is based on the principle of similitude (similia similibus curentur) using medicines that cause effects similar to the symptoms of disease in order to stimulate the reaction of the organism. Such ...
Estudos sobre o uso de NbCl5 como ácido de Lewis em reações de Povarov
The aim of this work was to investigate the use of NbCl5 as Lewis acid in cycloadittion reactions [Reaction Aza-Diels-Alder (Povarov)] between Schiff bases and enol ethers. Comparison of reaction yields, obtained products ...