scholarly journals Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

2021 ◽  
Vol 17 ◽  
pp. 115-123
Author(s):  
Michał Mateusz Więcław ◽  
Bartłomiej Furman
Keyword(s):  
Asymmetric Synthesis ◽  
Multicomponent Reaction ◽  
Direct Synthesis ◽  
X Ray

Herein we present the direct asymmetric synthesis of tetrazole-functionalized 1-deoxynojirimycin derivatives from simple sugars via a Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi–azide multicomponent reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title products. Finally, some surprising observations regarding the mechanism of their formation were made.

scholarly journals Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

2020 ◽  
Author(s):  
Michał Mateusz Więcław ◽  
Bartłomiej Furman
Keyword(s):  
Asymmetric Synthesis ◽  
Direct Synthesis ◽  
X Ray

Herein we present the direct asymmetric synthesis of tetrazole-functionalized 1-deoxynojirimycin derivatives from simple sugars via a Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi-azide multi-component reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title products. Finally, some surprising observations regarding the mechanism of their formation were made.

scholarly journals Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

2018 ◽  
Vol 14 ◽  
pp. 2789-2798 ◽  
Author(s):  
Camila S Pires ◽  
Daniela H de Oliveira ◽  
Maria R B Pontel ◽  
Jean C Kazmierczak ◽  
Roberta Cargnelutti ◽  
...  
Keyword(s):  
Multicomponent Reaction ◽  
Functional Group ◽  
Diazo Compound ◽  
Molecular Iodine ◽  
Multicomponent Synthesis ◽  
One Pot ◽  
X Ray ◽  
Dehydrogenative Coupling ◽  
Reflux Temperature

A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1H-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl diselenides. The reactions were conducted in MeCN as solvent at reflux temperature under air. The methodology presents a large functional group tolerance to electron-deficient, electron-rich, and bulky substituents and gave the expected products in good to excellent yields. The synthesized 1,3-diphenyl-4-(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis.

scholarly journals Resonant-XRD Characterization of Nanoalloyed Au-Pd Catalysts for the Direct Synthesis of H2O2: Quantitative Analysis of Size Dependent Composition of the Nanoparticles †

2019 ◽  
Vol 9 (15) ◽  
pp. 2959 ◽  
Author(s):  
Paolo Centomo ◽  
Patrizia Canton ◽  
Claudio Burato ◽  
Carlo Meneghini ◽  
Marco Zecca
Keyword(s):  
Quantitative Analysis ◽  
Metal Nanoparticles ◽  
Metal Surface ◽  
Bimetallic Nanoparticles ◽  
Amorphous Polymer ◽  
Direct Synthesis ◽  
Relative Number ◽  
Pd Catalysts ◽  
X Ray

The focus of this work is on the relationship between the quantitative structural characterization of bimetallic Au-Pd nanoparticles dispersed in an amorphous polymer matrix and their catalytic activity in the direct synthesis of hydrogen peroxide (DS reaction). Resonant X-ray powder diffraction with synchrotron radiation was employed to probe selectively and to reveal fine details of the structure of bimetallic nanoparticles embedded in the support. The semi-quantitative analysis of the resonant X-ray powdered diffraction data, made on a large number of metal nanoparticles, shows that in one of the polymer-supported Au-Pd catalyst for the DS reaction (P75) featured by an overall molar Pd/Au of about 5.54, the smallest metal nanoparticles (MNPs), which account for more than 99.9% of the total MNPs number and for more than 95% of the metal surface, are formed by practically pure palladium. The relative number of bimetallic alloyed nanoparticles is very small (less than 4 × 102 ppm) and they contribute to only about 2% of the total metal surface. In a second gold-enriched catalyst (P50) with an overall molar Pd/Au of 1.84, the proportion of the bimetallic alloyed nanoparticles increased to about 97% and they account for about 99% of the metal surface. As a result of the metal intermixing, the catalytic productivity for the DS reaction increased from 97 to 109 mmolH2O2/molH2, owing to the gold-promotion of palladium.

scholarly journals Temperature-programmed surface reactions of methanol and dimethyl ether on bifunctional catalysts for the direct synthesis of dimethyl ether from syngas

2018 ◽  
Vol 243 ◽  
pp. 00002
Author(s):  
Olga Vodorezova ◽  
Pavel Musich ◽  
Natalia Karakchieva ◽  
Lothar Heinrich ◽  
Irina Kurzina
Keyword(s):  
Dimethyl Ether ◽  
Direct Synthesis ◽  
Bifunctional Catalyst ◽  
Bifunctional Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Physical Mixing ◽  
Stage Synthesis ◽  
Temperature Programmed ◽  
Synthesis Of Dimethyl Ether

Dimethyl ether (DME) can be used as a replacement for diesel fuel in transportation. The catalytic effectiveness of bifunctional catalysts for DME one-stage synthesis from carbon monoxide and hydrogen was estimated in the paper. Bifunctional catalysts CuZnAl/HZSM-5, CuZnAlCr/HZSM-5, and CuZnAlZr/HZSM-5 were obtained by physical mixing of CuZnAl(Cr/Zr)– Ох and HZSM-5 components and were characterized by BET, X-ray diffraction, and temperatureprogrammed surface reaction methods. Based on the TPSR results, the mechanism of the interaction of methanol and DME with the surface of the bifunctional catalyst was studied. It was found that the temperature range of the greatest catalytic activity was 240–260 °С.

scholarly journals Direct Synthesis of (K0.5Na0.5)NbO3Powders by Mechanochemical Method

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Nguyen Duc Van
Keyword(s):  
Milling Time ◽  
Direct Synthesis ◽  
Weight Ratio ◽  
Intermediate Species ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
X Ray ◽  
Milling Parameters ◽  
First Time ◽  
Carbonato Complex

The synthesis and structural properties of lead-free piezoelectric (K0.5Na0.5)NbO3powders prepared by mechanochemical method using Nb2O5, K2CO3, and Na2CO3as starting materials were reported. X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy were used to characterize the prepared samples. Results showed that, for the first time, by selecting the milling speed of 600 rpm and the ball-to-powder weight ratio of 35 : 1 as milling parameters, pure (K0.5Na0.5)NbO3crystalline phase was obtained directly in the as-milled samples after 5 h of milling time. The existence of a carbonato complex betweenCO32−and Nb5+ions as an intermediate species of the formation of (K0.5Na0.5)NbO3was also found.

Exploiting the Multidentate Nature of Chiral Disulfonimides in a Multicomponent Reaction for the Asymmetric Synthesis of Pyrrolo[1,2-a ]indoles: A Remarkable Case of Enantioinversion

2016 ◽  
Vol 128 (10) ◽  
pp. 3489-3493 ◽  
Author(s):  
Alicia Galván ◽  
Adán B. González-Pérez ◽  
Rosana Álvarez ◽  
Angel R. de Lera ◽  
Francisco J. Fañanás ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Multicomponent Reaction ◽  
Remarkable Case

scholarly journals Photocatalytic Abatement of Volatile Organic Compounds by TiO2 Nanoparticles Doped with Either Phosphorous or Zirconium

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2121 ◽  
Author(s):  
Melodj Dosa ◽  
Marco Piumetti ◽  
Samir Bensaid ◽  
Tahrizi Andana ◽  
Camilla Galletti ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Direct Synthesis ◽  
Ethylene Oxidation ◽  
Oxidation Reactions ◽  
X Ray ◽  
Binary Oxides ◽  
Ethylene Conversion ◽  
Vis Spectroscopy ◽  
Volatile Organic ◽  
Propylene Conversion

The aim of this work is to study the activity of novel TiO2-based photocatalysts doped with either phosphorus or zirconium under a UV-Vis source. A set of mesoporous catalysts was prepared by the direct synthesis: TiO2_A and TiO2_B (titanium oxide synthesized by two different procedures), P-TiO2 and Zr-TiO2 (binary oxides with either nonmetal or metal into the TiO2 framework). Complementary characterizations (N2 physisorption at 77 K, X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analysis, X-ray Photoelectron Spectroscopy (XPS), and (DR)UV-Vis spectroscopy) were used to investigate the physicochemical properties of the prepared catalysts. Then, the photocatalysts were tested for the oxidation of propylene and ethylene under UV-Vis light. As a result, the most promising catalyst for both the propylene and ethylene oxidation reactions was the P-TiO2 (propylene conversion = 27.8% and ethylene conversion = 13%, TOS = 3 h), thus confirming the beneficial effect of P-doping into the TiO2 framework on the photocatalytic activity.

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