S-Triggered Schmidt-type Rearrangement of Vinyl Azides to Access N-Aryl-(trifluoromethylsulfinyl)acetamides

Author(s):  
Zhenhua Liu ◽  
Tian Yu ◽  
Longhua Li ◽  
Wei Fu ◽  
Xingxing Gan ◽  
...  

A novel S-induced Schmidt-type rearrangement of vinyl azides with CF3SO2Na is reported, which is mediated by triphosgene (BTC) under mild reaction conditions. A wide range of N-arylated 2-(trifluoromethylsulfinyl)acetamieds, for the...

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.


2019 ◽  
Vol 16 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Reshma Nagpal ◽  
Jitender Bhalla ◽  
Shamsher S. Bari

Background:A lot of advancement has been made in the area of β-lactams in recent times. Most of the research is targeted towards the synthesis of novel β-lactams, their functionalization and exploring their biological potential. The C-3 functionalization of β-lactams has continued to attract considerable interest of the scientific community due to their utility as versatile intermediates in organic synthesis and their therapeutic applications. This has led to the significant increase in efforts towards developing efficient and economic strategies for C-3 functionalized β-lactams.Objective:The present review aims to highlight recent advancement made in C-3 functionalization of β-lactams.Conclusion:To summarize, functionalization of β-lactams at C-3 is an essential aspect of β-lactam chemistry in order to improve/modify its synthetic utility as well as biological potential. The C-3 carbocation equivalent method has emerged as an important and convenient strategy for C-3 functionalization of β-lactam heterocycles which provides a wide range of β-lactams viz. 3-alkylated β-lactams, 3-aryl/heteroarylated β-lactams, 3- alkoxylated β-lactams. On the other hand, base mediated functionalization of β-lactams via carbanion intermediate is another useful approach but their scope is limited by the requirement of stringent reaction conditions. In addition to this, organometallic reagent mediated α-alkylation of 3-halo/3-keto-β-lactams also emerged as interesting methods for the synthesis of functionalized β-lactams having good yields and diastereoselectivities.


2020 ◽  
Vol 17 ◽  
Author(s):  
Mohsen A.-M. Gomaa ◽  
Huda A. Ali

Background : The reactivity of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5-one DCNP 1 and its derivatives makes it valuable as a building block for the synthesis of heterocyclic compounds like pyrazolo-imidazoles, - thiazoles, spiropyridines, spiropyrroles, spiropyrans and others. As a number of publications have reported on the reactivity of DCNP and its derivatives, we compiled some features of this interesting molecule. Objective: This article aims to review the preparation of DCNP, its reactivity and application in heterocyclic and dyes synthesis. Conclusion: In this review we have provided an overview of recent progress in the chemistry of DCNP and its significance in synthesis of various classes of heterocyclic compounds and dyes. The unique reactivity of DCNP offers unprecedentedly mild reaction conditions for the generation of versatile cynomethylene dyes from a wide range of precursors including amines, α-aminocarboxylic acids, their esters, phenols, malononitriles and azacrown ethers. We anticipate that more innovative transformations involving DCNP will continue to emerge in the near future.


2016 ◽  
Vol 12 ◽  
pp. 2627-2635 ◽  
Author(s):  
Federica Santoro ◽  
Matteo Mariani ◽  
Federica Zaccheria ◽  
Rinaldo Psaro ◽  
Nicoletta Ravasio

The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.


2019 ◽  
Vol 15 ◽  
pp. 1523-1533 ◽  
Author(s):  
András György Németh ◽  
György Miklós Keserű ◽  
Péter Ábrányi-Balogh

A new multicomponent reaction has been developed between isocyanides, sulfur and alcohols or thiols under mild reaction conditions to afford O-thiocarbamates and dithiocarbamates in moderate to good yields. The one-pot reaction cascade involves the formation of an isothiocyanate intermediate, thus a catalyst-free synthesis of isothiocyanates, as valuable building blocks from isocyanides and sulfur is proposed, as well. The synthetic procedure suits the demand of a modern organic chemist, as it tolerates a wide range of functional groups, it is atom economic and easily scalable.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3393 ◽  
Author(s):  
Sergey I. Uskov ◽  
Dmitriy I. Potemkin ◽  
Leniza V. Enikeeva ◽  
Pavel V. Snytnikov ◽  
Irek M. Gubaydullin ◽  
...  

Pre-reforming of propane was studied over an industrial nickel-chromium catalyst under pressures of 1 and 5 bar, at a low steam to carbon molar ratio of 1, in the temperature range of 220–380 °C and at flow rates of 4000 and 12,000 h−1. It was shown that propane conversion proceeded more efficiently at low pressure (1 atm) and temperatures above 350 °C. A genetic algorithm was applied to search for kinetic parameters better fitting experimental results in such a wide range of experimental conditions. Power law and Langmuir–Hinshelwood kinetics were considered. It was shown that only Langmuir–Hinshelwood type kinetics correctly described the experimental data and could be used to simulate the process of propane pre-reforming and predict propane conversion under the given reaction conditions. The significance of Langmuir–Hinshelwood kinetics increases under high pressure and temperatures below 350 °C.


2020 ◽  
Vol 117 (7) ◽  
pp. 3446-3450 ◽  
Author(s):  
Benginur Demir ◽  
Thomas Kropp ◽  
Keishla R. Rivera-Dones ◽  
Elise B. Gilcher ◽  
George W. Huber ◽  
...  

We show that platinum displays a self-adjusting surface that is active for the hydrogenation of acetone over a wide range of reaction conditions. Reaction kinetics measurements under steady-state and transient conditions at temperatures near 350 K, electronic structure calculations employing density-functional theory, and microkinetic modeling were employed to study this behavior over supported platinum catalysts. The importance of surface coverage effects was highlighted by evaluating the transient response of isopropanol formation following either removal of the reactant ketone from the feed, or its substitution with a similarly structured species. The extent to which adsorbed intermediates that lead to the formation of isopropanol were removed from the catalytic surface was observed to be higher following ketone substitution in comparison to its removal, indicating that surface species leading to isopropanol become more strongly adsorbed on the surface as the coverage decreases during the desorption experiment. This phenomenon occurs as a result of adsorbate–adsorbate repulsive interactions on the catalyst surface which adjust with respect to the reaction conditions. Reaction kinetics parameters obtained experimentally were in agreement with those predicted by microkinetic modeling when the binding energies, activation energies, and entropies of adsorbed species and transition states were expressed as a function of surface coverage of the most abundant surface intermediate (MASI, C3H6OH*). It is important that these effects of surface coverage be incorporated dynamically in the microkinetic model (e.g., using the Bragg–Williams approximation) to describe the experimental data over a wide range of acetone partial pressures.


Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1809
Author(s):  
Shuai Li ◽  
Xia Wang ◽  
Xin-Ge Yang ◽  
Gui-Quan Yu ◽  
Xue-Qiang Wang

A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 997
Author(s):  
Nicolas Vogt ◽  
Vasily Sivchik ◽  
Aaron Sandleben ◽  
Gerald Hörner ◽  
Axel Klein

The organonickel complexes [Ni(Phbpy)X] (X = Br, OAc, CN) were obtained for the first time in a direct base-assisted arene C(sp2)–H cyclometalation reaction from the rather unreactive precursor materials NiX2 and HPhbpy (6-phenyl-2,2′-bipyridine) or from the versatile precursor [Ni(HPhbpy)Br2]2. Different from previously necessary C‒Br oxidative addition at Ni(0), an extended scan of reaction conditions allowed quantitative access to the title compound from Ni(II) on synthetically useful timescales through base-assisted C‒H activation in nonpolar media at elevated temperature. Optimisation of the reaction conditions (various bases, solvents, methods) identified 1:2 mixtures of acetate and carbonate as unrivalled synergetic base pairs in the optimum protocol that holds promise as a readily usable and easily tuneable access to a wide range of direct nickelation products. While for the base-assisted C‒H metalation of the noble metals Ru, Ir, Rh, or Pd, this acetate/carbonate method has been established for a few years, our study represents the leap into the world of the base metals of the 3d series.


Synlett ◽  
2019 ◽  
Vol 30 (12) ◽  
pp. 1442-1446 ◽  
Author(s):  
Zhang-qi Lin ◽  
Chao-dong Li ◽  
Zi-chun Zhou ◽  
Shuai Xue ◽  
Jian-rong Gao ◽  
...  

A simple and highly efficient method for the preparation of tetrasubstituted NH-pyrrole from a wide range of chalcones and diethyl iminodiacetates via a Cu(OAc)2-promoted oxidation/[3+2]cycloaddition/aromatization cascade reaction has been developed. This reaction proceeds through dehydrogenations, deamination, and oxidative cyclization, affording the corresponding products in good to excellent yields. This convenient methodology for constructing tetrasubstituted NH-pyrroles has several advantages over existing methods, such as the use of easily accessible chalcones and readily available diethyl iminodiacetates, and mild reaction conditions. A wide range of substrates are tolerated.


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