Search results for "Benzyl"
showing 10 items of 878 documents
Chemistry and Photochemistry of 2,6-Bis(2-hydroxybenzilidene)cyclohexanone. An Example of a Compound Following the Anthocyanins Network of Chemical R…
2014
The kinetics and thermodynamics of the 2,6-bis(2-hydroxybenzilidene)cyclohexanone chemical reactions network was studied at different pH values using NMR, UV-vis, continuous irradiation, and flash photolysis. The chemical behavior of the system partially resembles anthocyanins and their analogue compounds. 2,6-Bis(2-hydroxybenzilidene)cyclohexanone exhibits a slow color change from yellow to red styrylflavylium under extreme acidic conditions. The rate constant for this process (5 × 10(-5) s(-1)) is pH independent and controlled by the cis-trans isomerization barrier. However, the interesting feature is the appearance of the colorless compound, 7,8-dihydro-6H-chromeno[3,2-d]xanthene, isolat…
Enantioselective Synthesis of Tetrahydroprotoberberines and Bisbenzylisoquinoline Alkaloids from a Deprotonated α-Aminonitrile
2011
Under controlled conditions, 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-1-carbonitrile can be quantitatively deprotonated in the α-position. Its alkylation directly furnishes 3,4-dihydroisoquinolines which can serve as starting materials for the preparation of various alkaloids. Here, the preparation of the benzylisoquinolines (+)-laudanidine, (+)-armepavine, and (+)-laudanosine as well as the tetrahydroprotoberberines (-)-corytenchine and (-)-tetrahydropseudoepiberberine using Noyori's asymmetric transfer hydrogenation are described. The dimeric alkaloids (+)-O-methylthalibrine and (+)-tetramethylmagnolamine were obtained from nonracemic precursors in Ullmann diaryl ether syntheses.
The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes
2006
Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercialTiO2samples (Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene wasCO2with small amounts of benzaldehyde. In the presence of water vapour, the activity ofTiO2Merck remained stable but greatly decreased if water was absent.TiO2Degussa P25 continuously deactivated, even …
Presence of plant hormones in composts made from organic fraction of municipal solid waste
2016
Composting is a process of the biological decomposition of organic matter under aerobic conditions. Composts made from waste may still contain other substances that influence plant growth and development, such as vitamins or plant growth substances (plant hormones). Application of products containing phytohormones has an effect on numerous physiological processes in plants. Among observable results are: improved condition of the root system, increased absorption of nutrients, improved stress and disease resistance and delayed aging. The purpose of the research was to analyse the occurrence of plant hormones in mature composts made from selectively collected organic fraction of household mun…
Determination of selected phthalates by gas chromatography–mass spectrometry in mural paintings from Palermo (Italy)
2013
Abstract Phthalate esters for decades, and probably even now, were used as softeners in water-based paintings. In general, these compounds are dangerous owing to their carcinogenicity and reproductive effects. Phthalates are not chemically but only physically bound to the matrices, hence, they may be leached into the environment and are ubiquitously found in environmental matrices. Considering that, construction is one of most important fields in Europe, and probably worldwide, with respect to its economic, technological and environmental impact. In the present work the phthalate esters content of several mural paintings was evaluated by gas chromatography–mass spectrometry (GC-MS). Because…
CCDC 711699: Experimental Crystal Structure Determination
2010
Related Article: S.Fustero, P.Bello, B.Fernandez, C.del Pozo, G.B.Hammond|2009|J.Org.Chem.|74|7690|doi:10.1021/jo9013436
CCDC 888651: Experimental Crystal Structure Determination
2013
Related Article: Antti Riisiö, Mikko M. Hänninen, Reijo Sillanpää|2012|CrystEngComm|14|7258|doi:10.1039/c2ce26027a
CCDC 967095: Experimental Crystal Structure Determination
2013
Related Article: Michael Giese, Markus Albrecht, Simon Steike, Anton Ackermann, Arto Valkonen, and Kari Rissanen|2013|Inorg.Chem.|52|7666|doi:10.1021/ic4008087
CCDC 780593: Experimental Crystal Structure Determination
2011
Related Article: M.Karna, M.Lahtinen, A.Kujala, P.-L.Hakkarainen, J.Valkonen|2010|J.Mol.Struct.|983|82|doi:10.1016/j.molstruc.2010.08.036
CCDC 1005277: Experimental Crystal Structure Determination
2014
Related Article: Michael Giese, Markus Albrecht, Arto Valkonen, Kari Rissanen|2015|Chemical Science|6|354|doi:10.1039/C4SC02762K