ChemInform Abstract: A New and Direct Synthesis of 1-Acylamino-2,6-diaryl Pyridinium Salts.

ChemInform ◽  
2010 ◽  
Vol 29 (39) ◽  
pp. no-no
Author(s):  
F. RIVIERE ◽  
V. ROMANENKO ◽  
M.-R. MAZIERES ◽  
M. SANCHEZ ◽  
J.-G. WOLF
Keyword(s):  
Direct Synthesis ◽  
Pyridinium Salts

Indolizines. I. A direct synthesis of acylindolizines from substituted pyridinium salts

1972 ◽  
Vol 25 (5) ◽  
pp. 1003 ◽  
Author(s):  
I Dainis
Keyword(s):  
Aldol Condensation ◽  
Direct Synthesis ◽  
Reaction System ◽  
Reaction Scheme ◽  
Aliphatic Acid ◽  
Pyridinium Salts ◽  
Thermal Cyclization ◽  
One Step ◽  
Competing Pathways

Several routes to 1-formylmethyl-2-methylpyridinium bromide have been investigated. Chichibabin cyclization of this salt to indolizine fails because the reaction system favours an intermolecular aldol condensation. A general one-step synthesis of acyl-and diacyl-indolizines from 1-(β-oxo)-alkyl-2-alkyl- and 1-(β-oxo)alkyl-2-benzyl-pyridinium salts is described. This synthesis, as effected by the anhydride of a weak aliphatic acid and its sodium salt, also gives isomeric products and these have provided a mechanistic reaction scheme of three competing pathways. 1-Acyl-2,3-disubstituted and 3-acyl-1,2-disubstituted indolizines are formed from the relevant salts by Chichibabin cyclization and subsequent in situ acylation. 1-Acetonyl-2-methylpyridinium bromide gives useful yields of 3-acyl-and 1,3-di-acyl-indolizines by this pathway and also via 1-acetonyl-2-acetylmethylene-l,2-dihydropyridine. The reaction of the corresponding 1-phenacyl salt involves acylated intermediates of type (14) and (15), and has provided evidence for the rearrangement of the diacylmethylides (15) to acylmethines (14). A facile thermal cyclization of 2-phenylpyridinium diphenacylmethylide to 3-benzoyl-1,2-diphenylindolizine is reported.

A new and direct synthesis of 1-acylamino-2,6-diaryl pyridinium salts

1998 ◽  
Vol 39 (27) ◽  
pp. 4809-4812 ◽  
Author(s):  
François Rivière ◽  
Vadim Romanenko ◽  
Marie-Rose Mazières ◽  
Michel Sanchez ◽  
Jean-Gérard Wolf
Keyword(s):  
Direct Synthesis ◽  
Pyridinium Salts

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.

Structure Guided Molecular Docking Assisted Alignment Dependent 3DQSAR Study on Steroidal Aromatase Inhibitors (SAIs) as Anti-breast Cancer Agents

2019 ◽  
Vol 16 (7) ◽  
pp. 808-817 ◽  
Author(s):  
Laxmi Banjare ◽  
Sant Kumar Verma ◽  
Akhlesh Kumar Jain ◽  
Suresh Thareja
Keyword(s):  
Breast Cancer ◽  
Molecular Docking ◽  
Aromatase Inhibitors ◽  
Direct Synthesis ◽  
3D Qsar ◽  
Chemotherapeutic Agents ◽  
Modeling Tools ◽  
Data Set ◽  
Wide Range ◽  
Steroidal Aromatase Inhibitors

Background: In spite of the availability of various treatment approaches including surgery, radiotherapy, and hormonal therapy, the steroidal aromatase inhibitors (SAIs) play a significant role as chemotherapeutic agents for the treatment of estrogen-dependent breast cancer with the benefit of reduced risk of recurrence. However, due to greater toxicity and side effects associated with currently available anti-breast cancer agents, there is emergent requirement to develop target-specific AIs with safer anti-breast cancer profile. Methods: It is challenging task to design target-specific and less toxic SAIs, though the molecular modeling tools viz. molecular docking simulations and QSAR have been continuing for more than two decades for the fast and efficient designing of novel, selective, potent and safe molecules against various biological targets to fight the number of dreaded diseases/disorders. In order to design novel and selective SAIs, structure guided molecular docking assisted alignment dependent 3D-QSAR studies was performed on a data set comprises of 22 molecules bearing steroidal scaffold with wide range of aromatase inhibitory activity. Results: 3D-QSAR model developed using molecular weighted (MW) extent alignment approach showed good statistical quality and predictive ability when compared to model developed using moments of inertia (MI) alignment approach. Conclusion: The explored binding interactions and generated pharmacophoric features (steric and electrostatic) of steroidal molecules could be exploited for further design, direct synthesis and development of new potential safer SAIs, that can be effective to reduce the mortality and morbidity associated with breast cancer.

α-Ketophosphonates in the Synthesis of α-iminophosphonates

2020 ◽  
Vol 7 (2) ◽  
pp. 226-238
Author(s):  
Petro P. Ony`sko ◽  
Tetyana I. Chudakova ◽  
Vladimir V. Pirozhenko ◽  
Alexandr B. Rozhenko
Keyword(s):  
Bond Cleavage ◽  
Direct Synthesis ◽  
Equilibrium Mixture ◽  
Primary Amines ◽  
Alkyl Amines ◽  
Protic Solvents ◽  
Metallic Salts ◽  
Direct Preparation ◽  
Stage Synthesis ◽  
Aprotic Dipolar Solvent

The potentialities of condensation of α-ketophosphonates with primary amines for direct synthesis of α-iminophosphonates have been revealed. Diesters of α-ketophosphonic acids react with the primary amines by two competitive pathways: with a formation of α-iminophosphonates or a C-P bond cleavage resulting in a hydrogen phosphonate and an acylated amine. In many cases, the latter undesirable pathway is dominant, especially for more nucleophilic alkyl amines. Using metallic salts of α-ketophosphonates avoids the C-P bond cleavage, allowing direct preparation of α-phosphorylated imines by the reaction with primary amines. This strategy provides an atom economy single-stage synthesis of iminophosphonates – precursors of bio relevant phosphorus analogs of α-amino acids. Methyl sodium iminophosphonates, bearing aryl or heteryl substituents at the imino carbon atom exist in solutions at room temperature as an equilibrium mixture of Z- and E-isomers. A configuration of the C=N bond can be controlled by the solvent: changing the aprotic dipolar solvent DMSO-d6 by water or alcohols leads to the change from a predominant Z-isomer to almost an exclusive E-form. In contrast, diesters of the respective iminophosphonates exist in non-protic solvents predominantly in Econfiguration. The solvent effect on E-Z stereochemistry is demonstrated by DFT calculations.

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.

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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