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Inmaculada Robina Silvia Gómez-Bujedo José G. Fernández-Bolaños José Fuentes 《合成通讯》2013,43(13):2379-2397
To prepare C-sulfonate derivatives of disaccharides two different strategies were followed. Thus 6- and 6′-C-sulfocellobiosides 4 and 10–12 were prepared starting from a suitably protected cellobioside. The 6′-C-sulfoaminocellobioside 18 was prepared by construction of the molecule through a glycosylation reaction. In both cases, the synthetic pathway involves regioselective tosylation, introduction of a sulfur atom by nucleophilic displacement with potassium thioacetate and oxidation with hydrogen peroxide. 相似文献
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Dr. Waqar Rizvi Naxhije Berisha Dr. Christopher Farley Dr. N. V. S. Dinesh K. Bhupathiraju Dr. Chrysafis Andreou Emaad Khwaja German V. Fuentes Dr. Moritz F. Kircher Dr. Ruomei Gao Dr. Charles Michael Drain 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(64):14517-14521
Distortion of nominally planar phthalocyanine macrocycles affects the excited state dynamics in that most of the excited-state energy decays through internal conversion. A click-type annulation reaction on a perfluorophthalocyanine platform appending a seven-membered ring to the β-positions on one or more of the isoindoles distorts the macrocycle and modulates solubility. The distorted derivative enables photoacoustic imaging, photothermal effects, and strong surface-enhanced resonance Raman signals. 相似文献
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Effect of methoxyl groups on the NMR spectra: configuration and conformation of natural and synthetic indanic and tetralinic structures
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Beatriz Lantaño José M. Aguirre Eleonora V. Drago Diego J. de la Faba Nicolás Pomilio Jorge D. Mufato 《Magnetic resonance in chemistry : MRC》2017,55(7):619-633
Here, we studied the influence of the methoxyl groups attached at C‐7 and C‐2′ of natural and synthetic 1‐arylindanes on the chemical shift of the signal of bibenzylic hydrogen and carbon atoms and J1,2 coupling constants. This influence was also analysed in natural 1‐aryltetralins and related compounds that possess methoxyl and/or hydroxyl groups bound at C‐8 and C‐2′. The methoxyl groups attached at C‐7 in indanes or at C‐8 in tetralins produce a deshielding signal at H‐1 and shield at C‐1 and a strong decrease in the value of J1,2 due to the pseudoequatorial location adopted by the aryl group bound at C‐1, avoiding an ‘A1,3 strain’. Furthermore, compounds with hydroxyl or methoxyl groups in C‐2′, in the absence of substituents of C‐7 or C‐8, present a strong deshielding signal at H‐1, strong shield of the C‐1 signal and a decrease in the value of J1,2. This is attributed to the stereoelectronic effects of the methoxyl or hydroxyl groups, which we have called ‘Asarone effect’. NOESY experiments were conducted to confirm the configuration and conformation of some of the compounds included in this work. This study shows that both effects, A1,3 strain and Asarone effect, must be taken into account when the structure of natural indanes and tetralins is analysed by using 1H‐NMR and 13C‐NMR spectra. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Earlier we noted that the hydroboration of the trimethylsilyl enol ether of an acyclic ketone results in an elimination of a trimethylsiloxyborane moiety with the subsequent formation of an olefin.1,2 The olefin formed then undergoes hydroboration giving a monoalcohol upon oxidation. (eq 1) We wish to report here on the utility of this sequence, illustrated in eq 1, in the reductive 1,2 transposition of acyclic ketones.3 相似文献
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Adilson Beatriz Roberto da Silva Gomes Mauricio Gomes Constantino Gil Valdo José da Silva Kleber Thiago de Oliveira 《Tetrahedron letters》2014
A bicyclo[6.2.1]undecane model compound of the core structure of the biologically active furanoheliangolide sesquiterpene was synthesized. This new and short route was developed by using a solvent-free Diels–Alder reaction between cyclopentadiene and 3-nitro-2-cyclohexenone, followed by simple transformations. Theoretical calculations were performed in order to understand reactivity aspects of the cycloaddition. 相似文献
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Leo Iu Jos A. Fuentes Mesfin E. Janka Kevin J. Fontenot Matthew L. Clarke 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(7):2142-2146
The hydroformylation of propene to give predominantly iso‐butanal has been achieved; class‐leading selectivity is possible even at higher temperatures that deliver fast conversion. Racemic rhodium complexes of bidentate phospholane phosphites derived from tropos‐biphenols and unusual solvent systems are the key to the selectivity observed. 相似文献