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921.
922.
Arnaud Boreux Aubin Lambion Dominic Campeau Marina Sanita Ruben Coronel Olivier Riant Fabien Gagosz 《Tetrahedron》2018,74(38):5232-5239
The synthesis of fluorinated synthetic intermediates has become a field of intense research in organic chemistry. In this article, we report the application of a gold-catalyzed rearrangement to the synthesis of β-trifluoromethylated α,β-unsaturated ketones. The scope of the reaction, as well as the valorization of the products in subsequent transformations has been investigated. This study allowed for the preparation of various CF3-substituted enones and fluorinated Diels-Alder adducts from easily accessible starting materials. 相似文献
923.
Vassiliki Theodorou Marina GogouMaria Philippidou Valentine RagoussisGeorgios Paraskevopoulos Konstantinos Skobridis 《Tetrahedron》2011,67(31):5630-5634
α,β-Unsaturated acids, through their acid chlorides, react with tritylamine in the presence of triethylamine under mild conditions, to afford in high yield and high regioselectivity the corresponding β,γ-unsaturated tritylamides. Detritylation with TFA generates quantitatively β,γ-unsaturated primary amides. An investigation of this deconjugative isomerization was performed. 相似文献
924.
925.
Christl Marcus Guérin Nicolas Totland Marina Gagné Alexandre Kazi Zakir Burrell Sean Synal Hans-Arno 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1611-1620
Journal of Radioanalytical and Nuclear Chemistry - A novel chronometry method is developed to date irradiated nuclear fuels. It is based on the measurement of two Cm isotopic ratios (244Cm/246Cm... 相似文献
926.
927.
Dmitry A. Gruzdev Evgeny N. Chulakov Galina L. Levit Marina A. Ezhikova Mikhail I. Kodess Victor P. Krasnov 《Tetrahedron: Asymmetry》2013,24(19):1240-1246
The acylative kinetic resolution of racemic 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline, 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine, and their non-fluorinated analogues with (S)-naproxen and N-phthaloyl-(S)-amino acyl chlorides has been carried out. It has been shown that the presence of fluorine atoms in the aromatic fragment of a heterocyclic amine results in the increasing stereoselectivity of acylation with (S)-naproxen acyl chloride and in a decrease in the efficiency of acylative kinetic resolution using N-phthaloyl-(S)-amino acyl chlorides. A method for the preparation of enantiopure (S)-6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (ee >99%) was developed. 相似文献
928.
Maddalena Bronzato Prof. Paolo Calvini Prof. Carlo Federici Prof. Sara Bogialli Prof. Gabriella Favaro Prof. Moreno Meneghetti Prof. Miriam Mba Prof. Marina Brustolon Prof. Alfonso Zoleo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(29):9569-9577
In this work, we present a wide‐range spectrochemical analysis of the degradation products from naturally aged paper. The samples obtained from wash waters used during the de‐acidification treatment of leaves from a 16th‐century‐printed book were analysed through NMR, IR, Raman UV/Vis, EPR and X‐ray fluorescence (XRF) spectroscopy and HPLC‐MS and inductively coupled plasma (ICP) analysis. By these methods we also studied some of the previous samples treated by acidification (sample AP) and catalytic hydrogenation (sample HP). Crossing all the data, we obtained precise indications about the main functional groups occurring on the degraded, water‐soluble cellulose oligomers. These results point out that the chromophores responsible for browning are conjugated carbonyl and carboxyl compounds. As a whole, we show that the analysis of wash waters, used in the usual conservation treatments of paper de‐acidification, gives much valuable information about both the conservation state of the book and the degradation reactions occurring on the leaves, due to the huge amount of cellulose by‐products contained in the samples. We propose therefore this procedure as a new very convenient general method to obtain precious and normally unavailable information on the cellulose degradation by‐products from naturally aged paper. 相似文献
929.
Dubravko Pavoković Renata Buđa Fran Andrašec Marin Roje Marina Cvjetko Bubalo Ivana Radojčić Redovniković 《Tetrahedron: Asymmetry》2017,28(5):730-733
Bioreduction mediated by plants is a highly selective and environmentally friendly approach to synthesise optically active alcohols. Herein the bioreduction of 1-(3,4)-dimethylphenyl)ethanone to the corresponding chiral alcohol 1-(3,4-dimethylphenyl)ethanol has been evaluated using nine different vegetables roots as biocatalysts. The chiral alcohol was prepared in yields ranging from 44.1% to 88.2%, and with enantiomeric excess up to 97.2% for the (S)-enantiomer. Sugar beet was the most promising among the tested vegetables roots. Therefore, sugar beet cell cultures (normal and transformed) were obtained and tested for the reduction as well, yielding the corresponding alcohol in the range from 62.1% to 88.2% yield and with enantiomeric excesses of >99%. Based on these results reported, there are no profound differences in the reductive capacity of undifferentiated cells and organs of the same plant species (sugar beet). Due to overall advantages of using cell cultures, we have highlighted this approach as a promising method for preparation of enantiomerically pure 1-(3,4-dimethylphenyl)ethanol. 相似文献
930.