Preparation of Pyridine Derivatives from the Corresponding 5-Acetal-1-carbonyl Compounds by Acid Promoted Cyclization

Heterocycles ◽  
2021 ◽  
Vol 102 (7) ◽  
pp. 1314
Author(s):  
Hiroyuki Konno ◽  
Hiromichi Mihara ◽  
Yuki Watanabe
Keyword(s):  
Carbonyl Compounds ◽  
Pyridine Derivatives

A FACILE SYNTHESIS AND REACTIONS OF AMINO SELENOLO[2,3-b]PYRIDINE CARBOXYLATE

2015 ◽  
Vol 12 (1) ◽  
pp. 3910-3918 ◽  
Author(s):  
Dr Remon M Zaki ◽  
Prof Adel M. Kamal El-Dean ◽  
Dr Nermin A Marzouk ◽  
Prof Jehan A Micky ◽  
Mrs Rasha H Ahmed
Keyword(s):  
Biological Activity ◽  
Carbonyl Compounds ◽  
Mass Spectra ◽  
The Other ◽  
Pyridine Derivatives ◽  
Facile Synthesis ◽  
High Biological Activity ◽  
Basic Hydrolysis ◽  
Pyridine Carboxylate ◽  
Hydrolysis Of

 Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f  which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.

Cyclizations of Alkoxyallenes: Mechanisms, Intermediates, ­Products – A Personal Account on Solved and Unsolved Problems with Unique Allene Building Blocks

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3291-3302 ◽  
Author(s):  
Hans-Ulrich Reissig ◽  
Reinhold Zimmer
Keyword(s):  
Natural Products ◽  
Carboxylic Acids ◽  
Carbonyl Compounds ◽  
Building Blocks ◽  
Ring Closure ◽  
Pyridine Derivatives ◽  
Personal Account ◽  
Three Component Reaction ◽  
Hydroxylamine Derivatives ◽  
Oxazine Derivatives

The additions of lithiated alkoxyallenes to electrophiles, such as carbonyl compounds, thioketones, imines, and nitrones, provide the expected primary addition products. These alkoxyallene intermediates undergo ring-closure reactions under quite different conditions. Whereas allenyl hydroxylamine derivatives spontaneously cyclize to 1,2-oxazine derivatives, the related allenyl amines, thiols, and alcohols require, with distinct exceptions, promotion by acids, base, silver(I), or gold(I). The different mechanisms of these processes are discussed in this account. The serendipitous discovery of a novel three-component reaction of lithiated alkoxyallenes, nitriles, and carboxylic acids followed by a cyclization to pyridine derivatives is also reported and the mechanism involved is illustrated. This account also compiles exemplary examples of natural products and other compounds prepared by subsequent reactions of alkoxyallene-based cyclization products, but the fascinating ring-closing event of the allenyl intermediates is the main focus of this report.1 Introduction2 Cyclizations of Allenyl Hydroxylamines to 1,2-Oxazine Derivatives3 Cyclizations of Allenyl Amines to Dihydropyrrole Derivatives4 Cyclizations of Allenyl Imines to Pyrroles – Discovery of a New Three-Component Synthesis of Pyridines5 Cyclizations of Allenyl Thiols to Vinylthiiranes and Dihydrothiophene Derivatives6 Cyclizations of Allenyl Alcohols to Dihydrofuran Derivatives7 Conclusions

Synthesis of fused imidazo[1,2-a]pyridines derivatives through cascade C(sp2)–H functionalizations

2019 ◽  
Vol 17 (41) ◽  
pp. 9140-9150 ◽  
Author(s):  
Bin Li ◽  
Nana Shen ◽  
Xinying Zhang ◽  
Xuesen Fan
Keyword(s):  
Carbonyl Compounds ◽  
Cascade Reactions ◽  
Pyridine Derivatives ◽  
Convenient Synthesis ◽  
Diazo Carbonyl Compounds

An efficient and convenient synthesis of fused imidazo[1,2-a]pyridine derivatives from the cascade reactions of 2-arylimidazo[1,2-a]pyridines with a-diazo carbonyl compounds via Rh(iii)-catalyzed C(sp2)–H functionalization/annulation is presented.

Silicon Assisted Sulfuration: Tetrachlorosilane-Sodium Sulfide-A New Potent Thionating Reagent for Carbonyl Compounds

2007 ◽  
Author(s):  
T. A. Salama ◽  
S. S. Elmorsy ◽  
A. M. Khalil ◽  
M. A. Ismail ◽  
A. S. El-Ahl
Keyword(s):  
Carbonyl Compounds ◽  
Sodium Sulfide

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

2019 ◽  
Author(s):  
Zhen Liu ◽  
Xiaohan Li ◽  
Tian Zeng ◽  
Keary Engle
Keyword(s):  
Carbonyl Compounds ◽  
Building Blocks ◽  
New Method ◽  
Carbon Based

A substrate-directed enantioselective <i>anti</i>-carboboration reaction of alkenes has been developed, wherein a carbon based nucleophile and a boron moiety are installed across the C=C bond through a 5- or 6-membered palladacycle intermediate. The reaction is promoted by a palladium(II) catalyst and a mondentate oxzazoline ligand. A range of enantioenriched secondary alkylboronate products were obtained with moderate to high enantioselectivity that could be further upgraded by recrystallization. This work represents a new method to synthesize versatile and valuable alkylboronate building blocks. Building on an earlier mechanistic proposal by Peng, He, and Chen, a revised model is proposed to account for the stereoconvergent nature of this transformation.

Tetranuclear Copper and Mononuclear Nickel Complex of the Schiff Base of (3Z)-3-Hydrazonobutan-2-One Oxime with Different Aromatic Carbonyl Compounds: Synthesis, Single Crystal X-Ray Structure, Catecholase Activity, Phenoxazinone Synthase Activity, Catalytic Study for the Homocoupling of Benzyl Amines

2019 ◽  
Author(s):  
Swaraj Sengupta ◽  
Sahanwaj Khan ◽  
Shyamal K. Chattopadhyay ◽  
Indrani Banerjee ◽  
Tarun K. Panda ◽  
...  
Keyword(s):  
Schiff Base ◽  
Single Crystal ◽  
Copper Complex ◽  
Carbonyl Compounds ◽  
Nickel Complex ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Phenoxazinone Synthase ◽  
Catecholase Activity ◽  
Aromatic Carbonyl Compounds

Synthesis and characterisation of one trinuclear copper complex, ([Cu<sub>3</sub>L<sub>3</sub>O]ClO<sub>4</sub>) (<b>1</b>) and one nickel complex ([Ni(L'H)<sub>2</sub>(dmso)<sub>2</sub>](ClO<sub>4</sub>)<sub>2</sub>) (<b>2</b>) with Schiff base ligands: (3Z)-3-((Z)-(1-(thiophen-2-yl)ethylidene)hydrazono)butan-2-one oxime (LH) and 1-(pyridin-2-yl)ethylidene)hydrazono)butan-2-one oxime (L<sup>'</sup>H). <b>1</b> shows high catecholase activity and has also been tested as a catalyst for the synthesis of benzylimine. <b>2 </b> shows phenoxazinone synthase activity.

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