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Główne metody syntezy soli piryliowych

Günther A., Soroka J. A.

Wiadomości Chemiczne

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2017

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[Z] 71, 1-2

87--108

EN

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.

2

Anion alkoksyallenowy w syntezie związków naturalnych i ich analogów

Busiak B., Utecht G., Jasiński M.

Wiadomości Chemiczne

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2016

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[Z] 70, 1-2

3--23

EN

Among diverse systems containing multiple bonds, cumulenes are recognized as the most reactive derivatives towards both nucleophilic and electrophilic agents, and for this reason, they are considered as important class of substrates for organic synthesis. Over the last three decades alkoxyallenes have been demonstrated as highly useful C3-building blocks for the construction of numerous N-, O-, and S-containing heterocycles, including enantiomerically pure compounds. Special attention has been paid to lithiated alkoxyallenes as suitable nucleophiles for the reactions with alkyl halides, strained heterocycles, carbonyl compounds and their derivatives. The presence of the allene unit in the initially formed adducts opens up several possibilities in the preparation of more complex systems. In this review, selected applications of lithiated alkoxyallenes in the synthesis of natural products and their analogues are discussed.

3

Sole winylofosfoniowe w syntezie organicznej

Mazurkiewicz R., Fryczkowska B., Gabański R.

Wiadomości Chemiczne

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2005

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[Z] 59, 3-4

249--274

EN

Vinylphosphonium salts are known for more than a century, but they started to attract significant attention of organic chemists only since 1964 when Schweizer demonstrated that the Michael addition of a nucleophile with a carbonyl function to vinylphosphonium salts results in phosphorus ylides, which can undergo the intramolecular Wittig reaction to carbo- and heterocyclic systems. The main synthetic routes to vinylphosphonium salts and a variety of their applications in organic syntheses are considered in detail in this review. Particular attention is given to the application of vinylphosphonium salts as versatile building blocks for syntheses of carbo- or heterocyclic systems in reactions with carbon, oxygen sulphur or nitrogen nucleophiles containing in a molecule a carbonyl function.