ChemInform Abstract: Pyrylium Salts with Long Alkyl Substituents. Part 3. 2,6-Diundecyl-4-methylpyrylium Perchlorate and Derived Pyridinium Salts.

ChemInform ◽  
2010 ◽  
Vol 28 (34) ◽  
pp. no-no
Author(s):  
M. BOGATIAN ◽  
G. MIHAI ◽  
M. PLAVETI ◽  
F. CHIRALEU ◽  
C. DELEANU ◽  
...  
2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus

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.


2014 ◽  
Vol 69 (5) ◽  
pp. 605-614 ◽  
Author(s):  
Nazar Pidlypnyi ◽  
Sandra Kaul ◽  
Sebastian Wolf ◽  
Martin H. H. Drafz ◽  
Andreas Schmidt

3-Methylindole reacts with pyridines in the presence of NBS to give indol-2-yl-pyridinium salts which were converted into their ylides by an anion exchange resin in its hydroxide form. Indol-3- amine was subjected to a nucleophilic ring transformation with pyrylium salts which resulted in the formation of indol-3-yl-pyridinium salts, the 2,4,6-trimethylpyridinium derivative of which proved to be unstable. The 2,4,6-triphenylpyridinium derivate was deprotonated to the corresponding ylide. The isomeric indol-2-yl and indol-3-yl derivatives are cycloimmonium ylides which are members of the compound class of heterocyclic mesomeric betaines (MB). By contrast, the ylide of indol- 2-yl-pyrrolidinium is a cycloammonium ylide. It was prepared by reaction of 3-methylindole with pyrrolidine in the presence of NBS, followed by deprotonation.


ChemInform ◽  
2010 ◽  
Vol 29 (50) ◽  
pp. no-no
Author(s):  
M. BOGATIAN ◽  
G. MIHAI ◽  
M. PLAVETI ◽  
F. CHIRALEU ◽  
M. MAGANU ◽  
...  

ChemInform ◽  
2008 ◽  
Vol 39 (32) ◽  
Author(s):  
Mariana Viorica Bogatian ◽  
Mircea Vinatoru ◽  
Gheorghe Bogatian ◽  
Demetra Nuta ◽  
Filip Chiraleu ◽  
...  

Synthesis ◽  
2019 ◽  
Vol 52 (04) ◽  
pp. 489-503 ◽  
Author(s):  
Yue Pang ◽  
Daniel Moser ◽  
Josep Cornella

Primary amino groups represent an ubiquitous category of functionalities in synthetic building blocks, drugs, and natural products. Therefore, such functionalities offer themselves as perfect handles for late-stage functionalization, and the development of robust and efficient strategies to transform these groups is highly desirable. Despite the extremely challenging activation of the C–N bond, the past few years have witnessed the rapid development of deaminative transformations using pyrylium salts as activating reagents. In most cases, the pyridinium salts formed were activated by single electron transfer, giving alkyl radicals which were used in a series of transformations via nickel and photoredox catalysis. This short review aims to give an overview to related properties of pyrylium salts, their historical significance, and summarize the recent progress in the field of deaminative transformations using these reagents.1 Introduction2 Pyrylium and Pyridinium Salts2.1 Historical Context2.2 Structure and Reactivity2.3 Pyrylium Synthesis2.4 Historical Context of the Reactivity of Pyridinium Salts3 Recent Progress on Deaminative Transformations of Primary Amino Groups by Pyrylium Salts3.1 Metal-Catalyzed Cross-Couplings3.2 Photoredox Catalysis and Photoinduced Reactions for C–C Bond Constructions3.3 Borylations3.4 SNAr Functionalization of Aminoheterocycles4 Conclusion


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