Wyniki wyszukiwania - BazTech

Ograniczanie wyników

1 Wiadomości Chemiczne

1 2017

Powiadomienia systemowe

Sesja wygasła!
Sesja wygasła!

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: pyrylium cation

Sortuj według:

Ogranicz wyniki do:

Główne metody syntezy soli piryliowych

Günther A., Soroka J. A.

Wiadomości Chemiczne

2017

[Z] 71, 1-2

87--108

Pyrylium salts are valuable organic aromatic compounds based on pyrylium cation, which are built from six-membered ring and contain one positively charged oxygen atom. The presence of a non-nucleophilic anion makes aromatic system stable. These salts are very sensitive for nucleophiles and react with them easily, especially 2,6-disubstituted ( positions) salts because of a lower density of electrons than that of 4-substitued ( position). They react with primary amine groups giving pyridinium salts. This mechanism runs through the stages of attack of nucleophile, ring opening and ring closing (SnANRORC). The synthesis of pyrylium salts is very useful and comfortable because of their ionic properties, obtained products are not soluble in diethyl ether or liquid alkanes, and can be easy isolated and purified from a reaction mixture. Pyrylium salts have a wide range of applications, such as laser dyes, fluorescent dyes, biological and chemical sensors, reactive matrices for MALDI-MS imaging of biologically active primary amines (e.g. amphetamine, dopamine) and many others especially as a universal substrate in the synthesis of heterocyclic compounds. In nature pyrylium ions occur only in structures of anthocyanins in tissues of higher plants and are used as food dyes. Herein we described selected properties and applications of pyrylium salts, chemical reactivities, and the most frequently used and useful methods of syntheses of pyrylium salts which can be used as starting materials to obtain different class of heterocyclic compounds.