scholarly journals Cu(OTf)2-Catalyzed Beckmann Rearrangement of Ketones Using Hydroxylamine-O-sulfonic Acid (HOSA)

Synthesis ◽  
2019 ◽  
Vol 51 (19) ◽  
pp. 3709-3714 ◽  
Author(s):  
Sailu Munnuri ◽  
Saumya Verma ◽  
Dinesh Chandra ◽  
Raghunath Reddy Anugu ◽  
John R. Falck ◽  
...  

The Beckmann rearrangement (BKR) of ketones to secondary amides often requires harsh reaction conditions that limit its practicality and scope. Herein, the Cu(OTf)2-catalyzed BKR of ketones under mild reaction conditions using hydroxylamine-O-sulfonic acid (HOSA), a commercial water soluble aminating agent, is described. This method is compatible with most functional groups and directly provides the desired amides in good to excellent yields.

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3272-3276
Author(s):  
Jawahar L. Jat ◽  
Saumya Verma ◽  
Puneet Kumar ◽  
Anil K. Khatana ◽  
Dinesh Chandra ◽  
...  

A zinc(II)-catalyzed single-step protocol for the Beckmann rearrangement using hydroxylamine-O-sulfonic acid (HOSA) as the nitrogen source in water was developed. This direct method efficiently produces secondary amides under open atmosphere in a pure form after basic aqueous workup. It is environmentally benign and operationally simple.


Langmuir ◽  
2013 ◽  
Vol 29 (26) ◽  
pp. 8402-8409 ◽  
Author(s):  
Qiaorong Han ◽  
Xiaohan Chen ◽  
Yanlian Niu ◽  
Bo Zhao ◽  
Bingxiang Wang ◽  
...  

Synthesis ◽  
2021 ◽  
Author(s):  
Travis Hammerstad ◽  
Pooja V. Hegde ◽  
Kathleen J. Wang ◽  
Courtney Aldrich

A convenient procedure for the chemoselective reduction of tertiary amides at room temperature in the presence of air and moisture using 1,3-diphenyldisiloxane (DPDS) has been developed. The reaction conditions are tolerant of a great number of functional groups including esters, nitriles, secondary amides, carbamates, sulfoxides, sulfones, sulfonyl fluorides, halogens, aryl-nitro groups, and arylamines. The conditions reported are the mildest to date and utilize EtOAc, a preferred solvent given its excellent safety profile and lower environmental impact. The ease of set up and broad chemoselectivity make this method attractive for organic synthesis. These results further demonstrate the utility of DPDS as a selective reducing agent.


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.


2020 ◽  
Vol 5 (11) ◽  
Author(s):  
Stephanie Santos Díaz ◽  
Hazim Al-Zubaidi ◽  
Amir C. Ross-Obare ◽  
Sherine O. Obare

AbstractFor many decades, organohalide and organophosphate compounds have shown significant detrimental impact on the environment. Consequently, strategies for their remediation continue to be an area of emerging need. The reduction of the chlorpyrifos pesticide, a molecule that bears both organohalide and organophosphate functional groups, is an important area of investigation due to it toxic nature. In this report, we demonstrate the effectiveness of the biological molecule, flavin mononucleotide (FMN) toward chemically reducing chlorpyrifos. The FMN was found to be highly active when anchored to nanocrystalline TiO2 surfaces. The results show new directions toward the remediation of organic contaminants under mild reaction conditions.


Molecules ◽  
2015 ◽  
Vol 20 (4) ◽  
pp. 6856-6865 ◽  
Author(s):  
Krzysztof Idzik ◽  
Karsten Nödler ◽  
Tobias Licha

2020 ◽  
Author(s):  
Hojoon Park ◽  
jin-quan yu

<div>Cycloaddition reactions provide an expeditious route to construct ring systems in a highly convergent and stereoselective manner. For a typical cycloaddition reaction to occur, however, the installation of multiple reactive functional groups (π-bonds, leaving group, etc.) are required within the substrates, compromising the overall efficiency or scope of the cycloaddition reaction. Here, we report a palladium-catalyzed [3+2] reaction that utilizes C(sp<sup>3</sup>)–H activation to generate the three-carbon unit for formal cycloaddition with maleimides. We implemented a strategy where the initial C(sp<sup>3</sup>)–H activation/olefin insertion would trigger a relayed, second remote C(sp<sup>3</sup>)–H activation to complete a formal [3+2] cycloaddition. The diastereoselectivity profile of this reaction resembles that of a typical pericyclic cycloaddition reaction in that the relationships between multiple stereocenters are exquisitely controlled in a single reaction. The key to success was the use of weakly coordinating amides as the directing group, as undesired Heck or alkylation pathways were preferred with other types of directing groups. The use of the pyridine-3-sulfonic acid ligands is critical to enable C(sp<sup>3</sup>)–H activation directed by this weak coordination. The method is compatible with a wide range of amide substrates, including lactams, which lead to novel spiro-bicyclic products. The [3+2] product is also shown to undergo a reductive desymmetrization process to access chiral cyclopentane bearing multiple stereocenters with excellent enantioselectivity.</div>


2018 ◽  
Vol 1 (1) ◽  
pp. 114-124 ◽  
Author(s):  
Jesie Silva ◽  
Lizebel Morante ◽  
Tesfamichael Demeke ◽  
Jacqueline Baah-Twum ◽  
Abel Navarro

The prevalence of antibiotics in water creates microbial resistance and has a negative impact on the ecosystem. Biomaterials such as spent tea leaves are rich in functional groups and are suitable for chemical modification for diverse applications. This research proposes the use of spent tea leaves of chamomile (CM), green tea (GT), and peppermint (PM) as structural scaffolds for the incorporation of carboxyl, sulfonyl, and thiol groups to improve the adsorption of Penicillin G (Pe). Adsorbents characterization reported a higher number of acidic functional groups, mainly in thiolated products. Scanning electron microscopy (SEM) analysis showed changes on the surfaces of the adsorbents due to reaction conditions, with a stronger effect on thiolated and sulfonated adsorbents. Elemental analysis by Energy dispersive X-ray spectrophotometry (EDS) corroborated the chemical modification by the presence of sulfur atoms and the increase in oxygen/carbon ratios. Batch experiments at different pH shows a strong pH-dependence with a high adsorption at pH 8 for all the adsorbents. The adsorption follows the trend CMs > GTs > PMs. Thiolation and sulfonation reported higher adsorptions, which is most likely due to the sulfur bridge formation, reaching adsorption percentages of 25%. These results create a new mindset in the use of spent tea leaves and their chemical modifications for the bioremediation of antibiotics.


RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 41229-41236
Author(s):  
Jitendra Kumar Yadav ◽  
Priyanka Yadav ◽  
Satish K. Awasthi ◽  
Alka Agarwal

Sulfonic acid functionalized over biguanidine fabricated silica-coated heterogeneous magnetic nanoparticles (NP@SO3H) have been synthesized, well characterized and explored for the first time, as an efficient and recyclable catalyst for N-formylation of primary amines under mild reaction conditions.


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