Phase-transfer catalysis in analytical chemistry

Phase-transfer catalysis (PTC) has been a well-established technique on the synthesis of organic chemicals for more than three decades. Its scope and underlying mechanistic features have been the subject of numerous studies and appear to be recognized and understood.

This review is intended to approach the subject by focusing on the extraction–preconcentration–derivatization/reaction prior to analysis and to chronicle recent progress made. We present the salient aspects of PTC modes followed by a brief review of mechanistic considerations including reaction mechanisms, selectivity, rates and kinetics pointing out to the potency of PTC in analytical chemistry. Specific guidelines are given on how to optimize a PTC-based analysis with respect to catalyst, solvent, reaction conditions and more, based on reaction characteristics.

Finally, using the PTC principles as a framework, selected real-life applications are provided, the capabilities and limitations of PTC are addressed for the purpose of direct analysis of organic analytes and certain advantages are highlighted.     

Phase-transfer catalysis in the chemistry of heterocyclic compounds

Methods for the preparation of heterocyclic systems, the chemical transformations of heterocyclic compounds under conditions of phase-transfer catalysis, and the use of quaternized heterocycles as phase-transfer catalysts are considered.     

Phase-transfer catalysis in the N-benzylation of adenine

A convenient phase-transfer catalysis in the N-benzylation of adenine is described. The benzylation of adenine with benzyl halides in a two-phase system containing phase-transfer catalyst gave 9-benzylated adenines as a major product accompanied with 3-benzylated adenines.     

Medicinal chemistry of tetrazoles

Properties of responsible for biological activity tetrazoles are considered. Examples are given of active pharmaceutical ingredients of modern drugs containing the tetrazole ring in the molecular structure. New publications on the synthesis and investigations of biological activity of promising tetrazole-containing compounds are cited.     

Phase-transfer dynamic combinatorial chemistry

A two-phase approach to dynamic combinatorial chemistry is described using disulfide exchange chemistry; the use of two phases significantly increases the possibilities and the scope of dynamic combinatorial chemistry by facilitating the combination of otherwise incompatible building blocks.     

Phase-transfer catalysis in the nickel-catalyzed cyanation of aryl halides

The nickel-catalyzed cyanation of aromatic halides under phase-transfer conditions is reported. Both liquid—liquid and solid—liquid techniques have been used, the former giving better yields and a higher catalyst turnover. The method provides a convenient and versatile route to aromatic nitriles.     

Phase-transfer and micellar catalysis in dehydrohalogenation reaction

Quaternary ammonium salts with a long hydrocarbon chain are a kind of bifunctional catalysts as the reactions in their presence proceeds by two catalytic pathways,i.e., phase-transfer and a micellar one. The former is inhibited by lipophilic anions such as chlorateetc. The structure-activity relationship for quaternary salts can be described quantitatively using Hansch -hydrophobicity constants.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11. pp. 2122–2134, November, 1995.     

Phase-transfer catalysis in reactions of electrophilic aromatic substitution

Electrophilic substitution in aromatic compounds under conditions of phase-transfer catalysis is considered. Catalysts of phase transfer of electrophilic reagents are used; their efficiency and the mechanism of their action in organic solvent-water systems are discussed.This review is based on materials of the report delivered at the Conference Phase-Transfer Catalysis. New Ideas and Methods (March 1994).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1895–1900, October, 1995.     

Phase-transfer catalysis in reactions with the participation of polyvinyl chloride

When polyvinyl chloride is dehydrochlorinated under conditions of phase transfer catalysis, the nature of the interface determines the supramolecular structure of the synthesized polyacetylene, the packing density of crystalline regions in the polyacetylene, and the chemical properties of the polymer. The ionic mechanism of catalysis of these reactions has been established.This review is based on materials reported at the Conference Phase-Transfer Catalysis: New Ideas and Methods(March, 1994).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1886–1894, October, 1995.     

Advances in the chemistry of tetrazoles (review)

The review is devoted to the newest advances in the chemistry of tetrazoles. New data on the electronic structures, crystal structures, and dipole moments are presented successively. The electronic, vibrational, NMR, and mass spectra are discussed. Data on the acid-base properties and tautomerism of tetrazoles are presented. Numerous methods for the preparation of tetrazole and mono- and disubstituted tetrazoles are reported. The chemical properties of tetrazoles, viz., electrophilic substitution at the ring carbon atom, nucleophilic substitution, alkylation, electrophilic and nucleophilic substitution in the side chain, and the effect of oxidizing and reducing agents, are discussed. Reactions that lead to cleavage of the tetrazole ring, viz., acylation and thermolysis, are examined separately. New data on the use of tetrazoles in medicine, biology, agriculture, the manufacture of polymeric materials, etc. are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1326, October, 1981.     

Phase-transfer catalysis in the nickel- and palladium-catalyzed formation of aryl and alkenyl sulfides

Aryl and alkenyl sulfides can be conveniently prepared from the corresponding halides and alkaline thiolates under phase transfer conditions in the presence of σ-Aryl-Ni[P(C₆H₅)₃]₂Cl or σ-Aryl-Pd[P(C₆H₅)₃]₂Br.     

Phase-transfer catalysis in reactions of 5-alkyl-3H-furan-2-ones with dichlorocarbene

Treatment of 5-alkyl-3H-furan-2-ones and 5-alkyl-3H-thiophen-2-ones with dichlorocarbene under conditions of phase-transfer catalysis at 20–90 °C results in insertion of the carbene at the C=C bond followed by skeletal rearrangement.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1995–1997, October, 1995.     

Phase-transfer catalysis in organic analysis: ultraviolet spectrophotometric determination of alcohols by formation of dithiocarbonates

After in situ derivatization to a dithiocarbonate (xanthate) in a carbon disulphide-aqueous sodium hydroxide two-phase system under phase-transfer catalysis conditions, a primary or secondary alcohol can be determined spectrophotometrically 300 nm.     

Phase transfer catalysis in the chemistry of aliphatic nitrocompounds

The methylation of trinitromethane (TNM) Na-salt under phase transfer catalysis (PTC) conditions was studied in a two-phase system (aqueous solution of TNM Na-salt-CH₃I). The obtained data revealed a relationship between the yield of the methylation product (1,1,1-trinitroethane) and the nature of the phase transfer catalyst and the degree of TNM anion transfer to the organic phase. The kinetic measurements showed that higher efficiency of methylation was achieved under PTC conditions than occurs in a homogeneous reaction due to the fact that the reaction proceeded in the CH₃I medium.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1086–1088, June, 1993.     

Green chemistry and catalysis in Mannich reaction

1. Download : Download high-res image (182KB)
2. Download : Download full-size image

     

Surface chemistry connecting heterogeneous catalysis,photocatalysis and plasmonic catalysis

正Chemical reactions catalyzed by solid catalysts have recently expanded rapidly from traditional heterogeneous catalytic reactions to photocatalytic reactions and further to plasmonic-catalytic reactions,however,the fundamental understanding of the commonalities and differences among heterogeneous catalysis,     

相转移催化在杂环化学中的应用

就近几年来相转移催化(PTC)在杂环化学中的应用,包括杂环化合物的合成,杂环化合物的化学修饰及杂环的转变进行了综述。     

Phase transfer catalysis in the chemistry of five-membered nitrogen-containing heterocycles

The methods for synthesis and reactions of five-membered nitrogen-containing heterocycles under the conditions of phase transfer catalysis as well as the application of quaternized heterocycles as phase transfer catalysts are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2115–2121, November, 1995.