Substrate selective synthesis of pyrazolo[1,5-a]pyridines through [3 + 2] cycloaddition of N-aminopyridines and β-nitro styrenes

RSC Advances ◽  
2015 ◽  
Vol 5 (53) ◽  
pp. 42961-42964 ◽  
Author(s):  
Chitrakar Ravi ◽  
Darapaneni Chandra Mohan ◽  
N. Naresh Kumar Reddy ◽  
Subbarayappa Adimurthy
Keyword(s):  
Selective Synthesis ◽  
Metal Free ◽  
Mild Conditions

Synthesis of 2 or 3-(hetero)aryl pyrazolo[1,5-a]pyridines through [3 + 2] cycloaddition ofN-aminopyridine with β-nitrostyrenes followed byin situdenitration under metal-free and mild conditions are described.

A Sequential Ugi-Smiles / Transition-Metal-Free Endo-Dig Conia-ene Cyclization: The Selective Synthesis of Saccharin Substituted 2,5-dihydropyrroles

2021 ◽  
Author(s):  
Hassan Seyrani ◽  
Sorour Ramezanpour ◽  
Aref Vaezghaemi ◽  
Farzad Kobarfard
Keyword(s):  
Transition Metal ◽  
Free Access ◽  
Selective Synthesis ◽  
Metal Free ◽  
Mild Conditions

A convenient, transition-metal-free access to a series of unprecedented saccharin substituted 2,5-dihydropyrroles is reported. This approach employs a post-Ugi-Smiles 5-endo-dig Conia-ene cyclization sequence in mild conditions while incorporating a series...

Metal-free phosphonation of heteroarene N-oxides with trialkyl phosphite at room temperature

2017 ◽  
Vol 15 (15) ◽  
pp. 3165-3169 ◽  
Author(s):  
Ming-Tao Chen ◽  
Xia You ◽  
Li-Gang Bai ◽  
Qun-Li Luo
Keyword(s):  
Room Temperature ◽  
Trialkyl Phosphite ◽  
Metal Free ◽  
Mild Conditions ◽  
Short Time

Heteroarene N-oxides were successfully converted to heteroarylphosphonates in a very short time under mild conditions through in situ activation with CBrCl3.

Organic Photoredox Catalysis for Pschorr Reaction: A Metal-Free and Mild Approach to 6H-Benzo[c]chromenes

Synlett ◽  
2018 ◽  
Vol 29 (17) ◽  
pp. 2311-2315 ◽  
Author(s):  
Gaofeng Feng ◽  
Jing-Yao He ◽  
Qi-Fan Bai ◽  
Chengan Jin
Keyword(s):  
Diazonium Salts ◽  
Eosin Y ◽  
Photoredox Catalysis ◽  
Synthetic Route ◽  
Metal Free ◽  
Mild Conditions ◽  
Pschorr Reaction

An expedient organic photoredox Pschorr reaction has been developed that opens up a synthetic route to 6H-benzo[c]chromenes. The process can be performed under mild conditions by using eosin Y as a photoredox catalyst and acetonitrile as the solvent. The diazonium salts can be either preformed or generated in situ from the corresponding amines with t-BuONO. The process is amenable to gram-sale synthesis of 6H-benzo[c]chromenes, which can be further transformed into both 6H-benzo[c]chromen-6-ones through oxidation or to 6H-benzo[c]chromen-6-amine through sp3 C–H bond amination. The protocol provides an attractive route for the synthesis of a library of 6H-benzo[c]chromes.

An Efficient Synthesis of Substituted Pyrazoles from One-Pot Reaction of Ketones, Aldehydes, and Hydrazine Monohydrochloride

Synlett ◽  
2018 ◽  
Vol 29 (08) ◽  
pp. 1071-1075 ◽  
Author(s):  
Vit Lellek ◽  
Cheng-yi Chen ◽  
Wanggui Yang ◽  
Jie Liu ◽  
Xuebao Ji ◽  
...  
Keyword(s):  
Efficient Synthesis ◽  
One Pot ◽  
Metal Free ◽  
Mild Conditions ◽  
Free Process ◽  
One Pot Condensation ◽  
Substituted Pyrazoles

An efficient, one-pot and metal-free process for the preparation of 3,5-disubstituted and 3,4,5-trisubstituted pyrazoles on multi-gram scale was developed. One-pot condensation of ketones, aldehydes and hydrazine monohydrochloride readily formed pyrazoline intermediates under mild conditions. Oxidation of pyrazolines, in situ, employing bromine afforded a wide variety of pyrazoles. The methodology offers a fast, and often chromatography-free protocol for the synthesis of 3,4,5-substituted pyrazoles in good to excellent yields. Alternatively, a more benign oxidation protocol affords 3,5-disubstituted or 3,4,5-trisubstituted pyrazoles by simply heating pyrazolines in DMSO under oxygen.

scholarly journals Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongmeng Wu ◽  
Cuibo Liu ◽  
Changhong Wang ◽  
Yifu Yu ◽  
Yanmei Shi ◽  
...  
Keyword(s):  
Binding Energy ◽  
Noble Metal ◽  
Atomic Hydrogen ◽  
Copper Sulfide ◽  
Low Cost ◽  
Water Electrolysis ◽  
Metal Free ◽  
Copper Nanowire

AbstractElectrocatalytic alkyne semi-hydrogenation to alkenes with water as the hydrogen source using a low-cost noble-metal-free catalyst is highly desirable but challenging because of their over-hydrogenation to undesired alkanes. Here, we propose that an ideal catalyst should have the appropriate binding energy with active atomic hydrogen (H*) from water electrolysis and a weaker adsorption with an alkene, thus promoting alkyne semi-hydrogenation and avoiding over-hydrogenation. So, surface sulfur-doped and -adsorbed low-coordinated copper nanowire sponges are designedly synthesized via in situ electroreduction of copper sulfide and enable electrocatalytic alkyne semi-hydrogenation with over 99% selectivity using water as the hydrogen source, outperforming a copper counterpart without surface sulfur. Sulfur anion-hydrated cation (S2−-K+(H2O)n) networks between the surface adsorbed S2− and K+ in the KOH electrolyte boost the production of active H* from water electrolysis. And the trace doping of sulfur weakens the alkene adsorption, avoiding over-hydrogenation. Our catalyst also shows wide substrate scopes, up to 99% alkenes selectivity, good reducible groups compatibility, and easily synthesized deuterated alkenes, highlighting the promising potential of this method.

Metal‐free direct oxidative C–N bond coupling of quinoxalin‐2(1H)‐ones with azoles under mild conditions

2021 ◽  
Author(s):  
Jingwen Guo ◽  
Lina Zhang ◽  
Xinyue Du ◽  
Liting Zhang ◽  
Yuepiao Cai ◽  
...  
Keyword(s):  
Metal Free ◽  
Mild Conditions

A metal-free radical cascade reaction of phosphine oxides with 2-aryloxy phenylacetylenes to assemble diphosphonyl xanthene derivatives

2021 ◽  
Author(s):  
Tao Fan ◽  
Yan Liu ◽  
Caina Jiang ◽  
Yanli Xu ◽  
Yan-Yan Chen
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Cascade Reaction ◽  
Phosphine Oxides ◽  
Metal Free ◽  
Mild Conditions ◽  
Xanthene Derivatives ◽  
Reaction Proceeds ◽  
Radical Cascade

A radical cascade reaction of 2-aryloxy phenylacetylene with phosphine oxides promoted by K2S2O8 was developed, provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with...

In situ construction of phenanthroline-based cationic radical porous hybrid polymers for metal-free heterogeneous catalysis

2021 ◽  
Vol 9 (12) ◽  
pp. 7556-7565
Author(s):  
Guojian Chen ◽  
Yadong Zhang ◽  
Ke Liu ◽  
Xiaoqing Liu ◽  
Lei Wu ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Hybrid Polymers ◽  
Metal Free ◽  
Oxidation Of Sulfides

Constructing phenanthroline-based cationic radical porous hybrid polymers as versatile metal-free heterogeneous catalysts for both oxidation of sulfides and CO2 conversion.

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