scholarly journals A metal-free approach for the synthesis of thiosulfonates from sulfonyl hydrazides

2021 ◽  
pp. 174751982110144
Author(s):  
Xue Li ◽  
WeiBo Liao ◽  
Bin Huang ◽  
YuanYuan Zhang ◽  
JiangWei Wang
Keyword(s):  
Metal Catalyst ◽  
Reaction Conditions ◽  
Metal Free ◽  
Efficient Transformation ◽  
Plausible Mechanism

Without any metal catalyst, an efficient transformation of a variety of sulfonyl hydrazides into the corresponding thiosulfonates mediated by NBS/DABCO under air is developed. The method utilizes mild reaction conditions, affords moderate to good yields of product, and tolerates a broad substrate scope. A plausible mechanism is proposed for the decomposition of the sulfonyl hydrazides and the construction of S(O2)–S bonds to form thiosulfonates.

Trichloroisocyanuric Acid Mediated Oxidative Dehydrogenation of Hydrazines­: A Practical Chemical Oxidation To Access Azo Compounds

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1103-1112
Author(s):  
Yingpeng Su ◽  
Xuan Liu ◽  
Jie Yu ◽  
Guiyan Cao ◽  
Rong Zhang ◽  
...  
Keyword(s):  
Scale Up ◽  
Chemical Oxidation ◽  
Azo Compounds ◽  
Reaction Conditions ◽  
Metal Free ◽  
Wide Range ◽  
Plausible Mechanism ◽  
Trichloroisocyanuric Acid ◽  
Economical Process ◽  
Operational Simplicity

A highly efficient, metal-free, chemical oxidation of hydrazines has been implemented using environmentally friendly TCCA as oxidant. This benign protocol provides straightforward access to a wide range of azo compounds in THF in excellent yield. Altogether, 35 azo compounds were obtained in this way and scale-up preparations were performed. Additionally, a plausible mechanism was also proposed. Step-economical process, mild reaction conditions, operational simplicity, high reaction efficiency, and easy scale-up highlight the practicality of this methodology.

scholarly journals Iodine(III) promotes cross-dehydrogenative coupling of N-hydroxyphthalimide and unactivated C(sp3)–H bonds

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Fufang Wu ◽  
Xuanzhen Han ◽  
Xuejian Li ◽  
Xiaobao Shen ◽  
Chang Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Coupling Reaction ◽  
Metal Catalyst ◽  
Coupling Reactions ◽  
Chemical Bonds ◽  
Reaction Conditions ◽  
Transition Metal Catalyst ◽  
Metal Free ◽  
Dehydrogenative Coupling ◽  
Ether Oxygen

AbstractCross-dehydrogenative coupling reactions provide a method to construct new chemical bonds by direct C–H activation without any pre-functionalization. Compared to functionalization of a C–H bond α- to ether oxygen, α- to carbonyl, or at a benzylic position, functionalization of unactivated hydrocarbons is difficult and often requires high temperatures, a transition-metal catalyst, or a superstoichiometric quantity of volatile, toxic, and explosive tert-butylhydroperoxide. Here, a cross-dehydrogenative C–O coupling reaction of N-hydroxyphthalimide with unactivated alkanes, nitriles, ethers, and thioethers has been realized by using iodobenzene diacetate as the radical initiator. The current protocol enables efficient functionalization of unactivated hydrocarbons and nitriles through inert C(sp3)–H bond activation under mild reaction conditions. O-substituted NHPI derivatives are generated in good yields under metal-free conditions.

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur
Keyword(s):  
Supramolecular Chemistry ◽  
Sulfonic Acid ◽  
Catalytic Efficiency ◽  
The Other ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bioactive Scaffolds ◽  
Wide Range ◽  
Efficient Alternative ◽  
Bioactive Heterocycles

: 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.

Synthesis of Pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by Alkyne-Carbonyl Metathesis

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Ehlers ◽  
Peter Langer ◽  
Marian Blanco Ponce ◽  
Silvio Parpart ◽  
Alexander Villinger ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Metathesis Reaction ◽  
Synthetic Methodology ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Modular Synthesis

AbstractA concise and modular synthesis of pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by a one-pot two-step reaction consisting of electrophilic acylation followed by an alkyne-carbonyl-metathesis reaction as the final cyclization step is reported. This developed synthetic methodology allows the facile synthesis of these heterocyclic core structures in mainly high overall yields under metal-free conditions. Reaction conditions are carefully optimized and display a novel supplement to access these tricyclic heterocyclic compounds.

scholarly journals Transition-metal-free allylation of 2-azaallyls with allyl ethers through polar and radical mechanisms

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guogang Deng ◽  
Shengzu Duan ◽  
Jing Wang ◽  
Zhuo Chen ◽  
Tongqi Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Allyl Ether ◽  
Metal Catalyst ◽  
Metal Free ◽  
Allyl Ethers ◽  
Bond Forming ◽  
Allyl Halides ◽  
Synthetic Utility ◽  
Insight Into ◽  
Allyl Esters

AbstractAllylation of nucleophiles with highly reactive electrophiles like allyl halides can be conducted without metal catalysts. Less reactive electrophiles, such as allyl esters and carbonates, usually require a transition metal catalyst to facilitate the allylation. Herein, we report a unique transition-metal-free allylation strategy with allyl ether electrophiles. Reaction of a host of allyl ethers with 2-azaallyl anions delivers valuable homoallylic amine derivatives (up to 92%), which are significant in the pharmaceutical industry. Interestingly, no deprotonative isomerization or cyclization of the products were observed. The potential synthetic utility and ease of operation is demonstrated by a gram scale telescoped preparation of a homoallylic amine. In addition, mechanistic studies provide insight into these C(sp3)–C(sp3) bond-forming reactions.

Chlorination of Arylaldehyde-Derived Arylsulfonylhydrazones with N-Chlorosuccinimide Leading to 1,2,4,5-Tetrazine Derivatives

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 69-74
Author(s):  
Yuan-Zhao Ji ◽  
Hui-Jing Li ◽  
Ying Liu ◽  
Yan-Chao Wu
Keyword(s):  
Potassium Hydroxide ◽  
Reaction Conditions ◽  
Metal Free ◽  
Vinyl Halides

It has been reported previously that treatment of aryl­ketone-derived arylsulfonylhydrazones with NXS/(nBu)4NX affords exclusively vinyl halides. In contrast, we have found that treatment of aryl­aldehyde-derived arylsulfonylhydrazones with N-chlorosuccinimide in the presence of potassium hydroxide affords 1,2,4,5-tetrazine derivatives in good to excellent yields. The present reactions are carried out under metal-free and mild reaction conditions.

Promotive Selectivity to C2-C3 Polyols From Alkaline Cellulose Hydrogenated by Ionic Liquid-stablized Ru Nanoparticles

2021 ◽  
Author(s):  
Mingrui Liu ◽  
Hua Wang
Keyword(s):  
Ionic Liquid ◽  
Ethylene Glycol ◽  
Conversion Rate ◽  
Metal Salt ◽  
Hydrogenation Reaction ◽  
Metal Catalyst ◽  
Ru Nanoparticles ◽  
Naoh Solution ◽  
Plausible Mechanism ◽  
Amorphous Part

Abstract Alkaline cellulose hydrogenolysis on metal catalyst was an effective way to get C2~C3 polyols. The alkaline cellulose was obtained by treating cellulose with 4 wt% NaOH solution. Ionic liquid-stablized Ru nanoparticles were prepared by reducing metal salt in ionic liquid. The SEM results indicate that the amorphous part of alkaline cellulose is helpful for getting the catalyst into the cavities to have a further hydrogenation reaction. When hydrogenolysis of alkaline cellulose over Ru/[Bmim]BF4 nanoparticles was conducted at 433 K, 63.78% of the substrate was converted with glycerol, 1,2-propanediol and ethylene glycol as main products of which selectivity was up to 58.91 %, whereas the conversion rate over Ru/C catalyst of alkaline cellulose was 59.23 % and only 26.11 % C2~C3 polyols were detected. Moreover, if the ionic liquid-stablized Ru nanoparticles were doped with 53.7 % Ni, the selectivity of C2~C3 polyols was promoted to 65.07 %. These results suggested the advantages of the ionic liquid-stablized Ru nanoparticles, especially doping with Ni, have potentials for promotive selectivity to C2~C3 alcohols. Put forward the plausible mechanism finally.

Pyridine mediated transition-metal-free direct alkylation of anilines using alcohols via borrowing hydrogen conditions

2020 ◽  
Vol 56 (88) ◽  
pp. 13607-13610 ◽  
Author(s):  
Rajagopal Pothikumar ◽  
Venugopal T Bhat ◽  
Kayambu Namitharan
Keyword(s):  
Transition Metal ◽  
Traditional Approach ◽  
Metal Catalyst ◽  
Transition Metal Catalyst ◽  
Metal Free ◽  
Borrowing Hydrogen ◽  
Activation Of Alcohols ◽  
Catalyst Systems ◽  
Hydrogen Reactions

Herein, we report aza-aromatics based organic mediators as a readily accessible alternative to the traditional approach of using transition metal catalyst systems for the activation of alcohols in borrowing hydrogen reactions.

An efficient noble-metal-free supported copper catalyst for selective nitrocyclohexane hydrogenation to cyclohexanone oxime

2017 ◽  
Vol 53 (20) ◽  
pp. 2930-2933 ◽  
Author(s):  
Qian-Qian Zhang ◽  
Jing Dong ◽  
Yong-Mei Liu ◽  
Yong Cao ◽  
He-Yong He ◽  
...  
Keyword(s):  
Noble Metal ◽  
Copper Catalyst ◽  
Metal Catalyst ◽  
Cyclohexanone Oxime ◽  
Noble Metal Catalyst ◽  
Metal Free ◽  
Supported Copper Catalyst

A green, inexpensive and robust heterogeneous non-noble metal catalyst comprising CuOx/SiO2 nanocomposites can efficiently convert nitrocyclohexane into cyclohexanone oxime under mild hydrogenation conditions.

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