A Simple Metal-free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2+2] Cycloaddition of Enaminones to Propyne Iminium Salts

2014 ◽  
Vol 69 (5) ◽  
pp. 554-566 ◽  
Author(s):  
Jure Bezenšek ◽  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Amalija Golobič ◽  
Katarina Stare ◽  
...  
Keyword(s):  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Simple Metal ◽  
One Pot ◽  
Alkyl Aryl ◽  
Metal Free ◽  
Iminium Salts

Herein a simple one-pot metal-free synthesis of 2,4,5-trisubstituted pyridines and pyridine Noxides by [2+2] cycloaddition of enaminones, which are prepared in situ from alkyl, aryl and heteroaryl methyl ketones using N,N-dimethylformamide dimethyl acetal (DMFDMA), and propyne iminium salts as electron-poor acetylenes, is described.

Reactions of Methyl Ketones and (Hetero)arylcarboxamides with N,N-Dimethylacetamide Dimethyl Acetal. A Simple Metal-Free Synthesis of 2,4,6-Trisubstituted Pyridines

2015 ◽  
Vol 68 (2) ◽  
pp. 184 ◽  
Author(s):  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Marta Kasunič ◽  
Silvo Zupančič ◽  
Jurij Svete ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Single Crystal ◽  
Ammonium Acetate ◽  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Closed Vessel ◽  
Simple Metal ◽  
One Pot ◽  
X Ray ◽  
Metal Free

Two metal-free syntheses of 2,4,6-trisubstituted pyridines 10a–m and 16a–j are described. N,N,6-Trimethyl-4-(substituted)pyridin-2-amines 10 were prepared from aryl or heteroaryl methyl ketones which were transformed with N,N-dimethylacetamide dimethyl acetal (DMADMA) into enaminones 4a–m, followed by treatment with ammonium acetate to give (Z)-3-amino-1-(substituted)but-2-en-1-ones 5a–m. These were treated with DMADMA under microwave irradiation in a closed vessel at 130°C, to give via intermediates 7–9 the final products 10a–m. N2,N2,N4,N4-Tetramethyl-6-(substituted) pyridine-2,4-diamines 16a–j were prepared in a one-pot synthesis from the corresponding carboxamides 11a–j by treatment with an excess of DMADMA in a closed vessel under microwave irradiation to give via intermediates 12a–j to 15a–j the final products 16a–j. X-Ray single crystal diffractometry studies of the enaminones 5c, 5g, 5i, 5j, and 5m and 2,4,6-trisubstituted pyridines 16a, 16b, 16g, 16i, and 16j were consistent with the expected structures.

I2–DMSO–PTSA: a simple and metal free oxidative cross coupling of imidazo[1,2-a]pyridines and methylketones

RSC Advances ◽  
2015 ◽  
Vol 5 (25) ◽  
pp. 19418-19425 ◽  
Author(s):  
Madhu Chennapuram ◽  
Narender Reddy Emmadi ◽  
Chiranjeevi Bingi ◽  
Krishnaiah Atmakur
Keyword(s):  
Cross Coupling ◽  
Methyl Ketones ◽  
Simple Metal ◽  
One Pot ◽  
Metal Free

A simple, metal free and selective oxidative cross-coupling promoted by I2–DMSO in presence of PTSA has been developed with the use of imidazo[1,2-a]pyridines (1) and methyl ketones (2) to access 3 in a one pot reaction.

scholarly journals Green ultrasound-assisted three-component click synthesis of novel 1H-1,2,3-triazole carrying benzothiazoles and fluorinated-1,2,4-triazole conjugates and their antimicrobial evaluation

2017 ◽  
Vol 67 (3) ◽  
pp. 309-324 ◽  
Author(s):  
Nadjet Rezki ◽  
Mohamed Reda Aouad
Keyword(s):  
Antimicrobial Activity ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Terminal Alkynes ◽  
One Pot ◽  
Alkyl Aryl ◽  
Antimicrobial Evaluation ◽  
Ultrasound Assisted ◽  
Click Synthesis

AbstractThe present study describes an efficient and ecofriendly, ultrasound, one-pot click cycloaddition approach for the construction of a novel series of 1,4-disubstituted-1,2,3-triazoles tethered with fluorinated 1,2,4-triazole-benzothiazole molecular conjugates. It involved three-component condensation of the appropriate bromoacetamide benzothiazole, sodium azide and 4-alkyl/aryl-5-(2-fluorophenyl)-3-(prop-2-ynylthio)-1,2,4-triazoles4a-ethrough a Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction. This approach involvesin situgeneration of azidoacetamide benzothiazole, followed by condensation with terminal alkynes in the presence of CuSO4/Na-ascorbate in aqueous DMSO under both conventional and ultrasound conditions. Some of the designed 1,2,3-triazole conjugates6a-owere recognized for their antimicrobial activity against some bacterial and fungal pathogenic strains.

Unconventional stereoselective one-pot synthesis of Knoevenagel-type indoles via in situ condensation of iminium salts with active methylene reagents

Tetrahedron ◽  
2013 ◽  
Vol 69 (51) ◽  
pp. 10858-10868 ◽  
Author(s):  
Angelo Ranise ◽  
Francesco Lucchesini ◽  
Matteo Caviglia ◽  
Silvana Alfei ◽  
Andrea Spallarossa ◽  
...  
Keyword(s):  
One Pot ◽  
Iminium Salts ◽  
One Pot Synthesis ◽  
Active Methylene

Radical Metal-Free Borylation of Aryl Iodides

Synthesis ◽  
2017 ◽  
Vol 49 (21) ◽  
pp. 4759-4768 ◽  
Author(s):  
Sandra Pinet ◽  
Mathieu Pucheault ◽  
Virginie Liautard ◽  
Mégane Debiais
Keyword(s):  
Steric Hindrance ◽  
Radical Mechanism ◽  
Electronic Effects ◽  
Simple Metal ◽  
Reaction Conditions ◽  
Metal Free ◽  
Aryl Iodides ◽  
Reaction Proceeds ◽  
Electronic Effects Of Substituents

A simple metal-free borylation of aryl iodides mediated by a fluoride sp2–sp3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.

Reactions of enaminones and related compounds with N,N-dimethylacetamide dimethyl acetal. A simple one-pot metal-free synthesis of polysubstituted benzene derivatives

Tetrahedron ◽  
2014 ◽  
Vol 70 (14) ◽  
pp. 2359-2369 ◽  
Author(s):  
Benjamin Prek ◽  
Jure Bezenšek ◽  
Marta Kasunič ◽  
Uroš Grošelj ◽  
Jurij Svete ◽  
...  
Keyword(s):  
Dimethyl Acetal ◽  
Benzene Derivatives ◽  
One Pot ◽  
Metal Free ◽  
Related Compounds

ChemInform Abstract: A Simple Metal-Free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2 + 2] Cycloaddition of Enaminones to Propyne Iminium Salts.

ChemInform ◽  
2015 ◽  
Vol 46 (1) ◽  
Author(s):  
Jure Bezensek ◽  
Benjamin Prek ◽  
Uros Groselj ◽  
Amalija Golobic ◽  
Katarina Stare ◽  
...  
Keyword(s):  
Simple Metal ◽  
Metal Free ◽  
Iminium Salts

scholarly journals Metal-free and solvent-free synthesis of m-terphenyls through tandem cyclocondensation of aryl methyl ketones with triethyl orthoformate

RSC Advances ◽  
2020 ◽  
Vol 10 (20) ◽  
pp. 12113-12118 ◽  
Author(s):  
Xiaoqin Xiao ◽  
Juan Luo ◽  
Zongjie Gan ◽  
Wengao Jiang ◽  
Qiang Tang
Keyword(s):  
Solvent Free ◽  
Triethyl Orthoformate ◽  
Tandem Reaction ◽  
Methyl Ketones ◽  
One Pot ◽  
Metal Free ◽  
Solvent Free Synthesis ◽  
Aryl Methyl

A facile metal-free and solvent-free benzannulation was developed for the construction of m-terphenyl derivatives starting from aryl methyl ketones and triethyl orthoformate. This is a tandem reaction which merged six steps into one-pot procedure.

scholarly journals One-Pot NBS-Promoted Synthesis of Imidazoles and Thiazoles from Ethylarenes in Water

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 893 ◽  
Author(s):  
Liang Chen ◽  
Huajian Zhu ◽  
Jiang Wang ◽  
Hong Liu
Keyword(s):  
One Pot ◽  
Metal Free ◽  
Reaction Proceeds ◽  
In Situ Formation

A facile and eco-friendly method has been developed for the synthesis of imidazoles and thiazoles from ethylarenes in water. The reaction proceeds via in situ formation of α-bromoketone using NBS as a bromine source as well as an oxidant, followed by trapping with suitable nucleophiles to provide the corresponding products in good yields under metal-free conditions.

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