Base-catalyzed rearrangement of N-(aryloxy)pyridinium salts. Effect of a 3-substituent in the pyridine ring upon orientation. Synthesis of novel tricyclic rings

1983 ◽  
Vol 48 (5) ◽  
pp. 690-695 ◽  
Author(s):  
Rudolph A. Abramovitch ◽  
Muthiah N. Inbasekaran ◽  
Shozo Kato ◽  
Teresa A. Radzikowska ◽  
Piotr Tomasik
Keyword(s):  
Pyridine Ring ◽  
Pyridinium Salts ◽  
Tricyclic Rings

Oxidation of polysubstituted pyridinium salts

1982 ◽  
Vol 47 (5) ◽  
pp. 1494-1502 ◽  
Author(s):  
Petr Nesvadba ◽  
Josef Kuthan
Keyword(s):  
Alkaline Medium ◽  
Electrophilic Substitution ◽  
Pyridine Ring ◽  
Potassium Ferricyanide ◽  
Pyridinium Salts ◽  
Complex Reaction

Oxidation of 1-substituted 2,4,6-triphenylpyridinium salts Ia-Ij with potassium ferricyanide in an alkaline medium was accompanied by contraction of the pyridine ring and formation of 1,2,3,5-tetrasubstituted pyrroles II. The derivative IIf underwent facile electrophilic substitution in the position 4. Contrary to compounds Ia-Ij, the 1-substituted-2,6-diphenylpyridinium salts IIIa,b were oxidized to give a complex reaction mixture containing 4-pyridones IVa,b.

scholarly journals Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

2018 ◽  
Vol 16 (1) ◽  
pp. 53
Author(s):  
Ptoton Mnangat Brian ◽  
Peter Musau
Keyword(s):  
Nitrogen Atom ◽  
Pyridine Ring ◽  
Aryl Halide ◽  
Protecting Groups ◽  
Pyridinium Salts ◽  
Substituted Pyridines ◽  
Benzyl Halides

This paper reports the synthesis and reactivity of different Benzyl derivative protecting groups. The synthesis and stability of Benzyl halides, 4-methoxybenzyl halides, 3,5-dimethoxybenzyl halides, 3,4-dimethoxybenzyl halides, 3,4,5-trimethoxybenzyl halide protecting groups and their reactivity towards nitrogen atom of a di-substituted pyridine ring in formation of pyridinium salts is also reported.

Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines

2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus
Keyword(s):  
Double Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Pyridinium Salts ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Pyrylium Salts

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

A Short Synthesis of the Plant Alkaloid 4-Methyl-2,6-naphthyridine

2019 ◽  
Vol 16 (12) ◽  
pp. 931-934 ◽  
Author(s):  
Alexandra Kamlah ◽  
Franz Bracher
Keyword(s):  
Pyridine Ring ◽  
Cross Coupling ◽  
Antirrhinum Majus ◽  
New Synthesis ◽  
Short Synthesis ◽  
Regioselective Oxidation ◽  
Key Steps

: A new synthesis of the 2,6-naphthyridine alkaloid 4-methyl-2,6-naphthyridine from Antirrhinum majus has been developed. Key steps are a regioselective oxidation of 3-bromo-4,5- dimethylpyridine to the corresponding 4-formyl derivative, and the annulation of the second pyridine ring by Suzuki-Miyaura cross-coupling using (E)-2-ethoxyvinylboronic acid pinacol ester as a masked acetaldehyde equivalent. This protocol gives the alkaloid in four steps starting from commercially available 3,4-dimethylpyridine in 15% overall yield. This annulation protocol should be useful for the synthesis of other condensed pyridines as well.

Synthesis of Metronidazole Derivatives Containing Pyridine Ring and Anticancer Activity

2016 ◽  
Vol 13 (4) ◽  
pp. 283-288 ◽  
Author(s):  
Jianping Yong ◽  
Canzhong Lu ◽  
Xiaoyuan Wu
Keyword(s):  
Anticancer Activity ◽  
Pyridine Ring

Electroanalysis of Tricyclic Psychotropic Drugs using Modified Electrodes

2019 ◽  
Vol 15 (4) ◽  
pp. 423-442 ◽  
Author(s):  
Mona Habibi-Kool-Gheshlaghi ◽  
Farnoush Faridbod ◽  
Mahya Karami Mosammam ◽  
Mohammad Reza Ganjali
Keyword(s):  
Psychotropic Drugs ◽  
Analytical Methods ◽  
Electrochemical Techniques ◽  
Modified Electrodes ◽  
Electroanalytical Methods ◽  
Drug Assays ◽  
Medical Importance ◽  
Tricyclic Rings ◽  
Easy Operation

Background: Tricyclic psychotropic drugs are defined as a tricyclic rings of the dibenzazepine group with the presence of sulfur and nitrogen atoms. They have been prescribed for antidepressive therapy over the years. Due to their medical importance, many analytical methods have been developed for their monitoring. However, benefits of electrochemical techniques such as costeffectiveness, fast, easy operation and non-destructiveness make them appropriate analytical methods for drug assays. Electrochemical determinations of pharmaceuticals require suitable working electrodes. During years, many electrodes are modified by a variety of modifiers and several sensors were developed based on them. In this regard, nanomaterials, due to their remarkable properties, are one of the most important choices. Objective: Here, the application of electroanalytical methods in the determination of electroactive tricyclic psychotropic drugs will be reviewed and the nanomaterials which are used for improvements of the working electrodes will be considered.

A new heterocyclic ring closure in ferricyanide oxidation of 2,4,6-triphenylpyridinium salts

1983 ◽  
Vol 48 (11) ◽  
pp. 3307-3314 ◽  
Author(s):  
Petr Nesvadba ◽  
Petr Štrop ◽  
Josef Kuthan
Keyword(s):  
Alkaline Solution ◽  
Heterocyclic Ring ◽  
Potassium Ferricyanide ◽  
Probable Mechanism ◽  
Ring Closure ◽  
Pyridinium Salts ◽  
Mechanism Of Formation ◽  
Pyrrole Derivatives ◽  
Quaternary Pyridinium Salts ◽  
Heterocyclic Derivatives

The quaternary pyridinium salts Ia-Ic react with alkaline solution of potassium ferricyanide to give the condensed heterocyclic derivatives IIIa, b, IV, whereas the salts Id-If give the pyrrole derivatives IIa-IIc under the same conditions. The diaza heterocycle IIIa reacts with methyl iodide to give methoiodide V, whereas by action of bromine it produces two monobromo derivatives VIa, b. The pyrrole derivatives IIa, b give monobromo derivatives IId, e on bromination. A probable mechanism of formation of the heterocyclic derivatives is discussed.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

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