scholarly journals Synthesis by Reversed Phase Transfer Catalysis and Characterization of Naphthol AS-D Pigment

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Eleonora Cornelia Crasmareanu ◽  
Vasile Simulescu ◽  
Gheorghe Ilia
Keyword(s):  
Carboxylic Acid ◽  
Organic Phase ◽  
Reaction Rate ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Coupling Reaction ◽  
Reversed Phase ◽  
Azo Coupling ◽  
Unconventional Method

Reversed phase transfer catalysis (RPTC) was applied to synthesize the Naphthol AS-D pigment. This method consists in the transfer of the aryldiazonium cation 4-nitrobenzenediazonium from aqueous medium into the organic phase (nitrobenzene) in the form of a lipophilic ions pair by the catalyst used (perfluorooctyl potassium sulfonates). In the organic phase the azo-coupling reaction between 4-nitrobenzenediazonium chloride and 3-hydroxy-2-carboxylic acid 2-methyl-anilide (Naphthol AS-D) takes place as coupling component. Using this unconventional method of synthesis, an increase of the reaction rate, combined with a higher purity of the product, was obtained.

scholarly journals Synthesis of Galectin Inhibitors by Regioselective 3′-O-Sulfation of Vanillin Lactosides Obtained under Phase Transfer Catalysis

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 115
Author(s):  
Karima Belkhadem ◽  
Yihong Cao ◽  
René Roy
Keyword(s):  
Carboxylic Acid ◽  
Sulfur Trioxide ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Aldehyde Group ◽  
Para Position ◽  
Knoevenagel Reaction ◽  
Aromatic Residue ◽  
Unsaturated Carboxylic Acid ◽  
Catalyzed Reactions

Vanillin-based lactoside derivatives were synthetized using phase-transfer catalyzed reactions from per-O-acetylated lactosyl bromide. The aldehyde group of the vanillin moiety was then modified to generate a series of related analogs having variable functionalities in the para- position of the aromatic residue. The corresponding unprotected lactosides, obtained by Zemplén transesterification, were regioselectively 3′-O-sulfated using tin chemistry activation followed by treatment with sulfur trioxide-trimethylamine complex (Men3N-SO3). Additional derivatives were also prepared from the vanillin’s aldehyde using a Knoevenagel reaction to provide extended α, β-unsaturated carboxylic acid which was next reduced to the saturated counterpart.

scholarly journals Oxidation of Cyclohexanol and Cyclohexanone by Monochromate Ions in Organic Solvents and on Solvent Free Microwave Irradiation under Phase Transfer Catalysis - A Comparative Study

2021 ◽  
Vol 33 (9) ◽  
pp. 2033-2037
Author(s):  
P. Bashpa ◽  
P. Rajendran ◽  
K. Bijudas
Keyword(s):  
Microwave Irradiation ◽  
Organic Phase ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Mineral Acid ◽  
Solvent Free ◽  
High Yield ◽  
Catalysis Condition ◽  
Solvent Free Condition ◽  
Spectral Technique

Oxidation of cyclohexanol and cyclohexanone were carried out by acidified monochromate ions in ethyl acetate and toluene under phase transfer catalysis and also in solvent free condition under microwave irradiation. The extraction of monochromate ions from aqueous medium to organic phase was carried by employing various phase transfer catalysts in the presence of mineral acids. The effect of [catalyst] and [mineral acid] on extraction of monochromate from aqueous phase to organic phase was also studied. The product obtained, namely adipic acid obtained with both reactants was characterized by its melting point and infrared spectral technique. The reaction was over within 15 min with more than 85% yield at a temperature of 323 K under microwave irradiation where as it gave around 70% yield at 353 K within 150 min under phase transfer catalysis condition. The enhanced reaction rate and high yield of product substantiate the application of phase transfer catalytic technique under microwave irradiation for organic synthesis. A suitable mechanism for the oxidation of substrates by monochromate under phase transfer catalysis is also suggested.

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