Zeisel reaction

ZEISEL REACTION. The deinethylation of an organic compound by treatment with hydriodic acid, which leaves a hydroxy group in place of the methoxy group, and fonns methyl iodide, which may readily be detennined quantitatively, as in the study of the amount of nietlioxy gioups present. 

Zeisel reaction /z -sSl/ The reaction of an ether with excess concentrated hydroiodic acid. On refluxing, a mixture of iodoalka-nes is formed ... 

The solvent systems used were those proposed by Waldi [257] and slightly modified by Pot silovI [178] (Table 72). The proportions of the components of the solvent mixture can be varied somewhat, depending on the nature of the silica gel, in order to achieve optimum separation. The best amount to apply is 2—5 fxg of pure substance or 20 [xg of crude extract in ethanolic solution. Colchicoside or other glycosidic alkaloids were applied after dissolving in a water-ethanol mixture. The sensitivity of the Oberlin-Zeisel reaction was about 1 (xg tropolone substance per spot. 

Visualisation 1. Dayhght 2. long wave UV light 3. Dragendorff reagent (No. 98) 4. characteristic and sensitive Oberlin-Zeisel reaction, ferric chloride reagent (No. 102) 5. iodoplatinate reagent (No. 147) ... 

Oberlin-Zeisel reaction (Rgt. No. 102) yields brown-blue. Isolated from Kreysigia multiflora,... 

Anderson and co-workers [16] used combined Zeisel reaction and gas chromatography to analyse acrylic copolymers. Acrylic esters were cleaved with hydriodic acid and gas chromatography was used for analysing the alkyl iodides so formed ... 

Holden84 used a method of measurement in which the methanol liberated by PM in a buffered solution of pectinic acid in ten minutes has been estimated by the Zeisel method. This procedure is much more complicated than that described above and must be regarded as unreliable on account of the rapid change in the pH of such reaction mixtures, even if buffered. 

Diagnostic reactions (40) that have been applied to dioscorine show the absence of methoxyl groups (Zeisel) and hydroxyl groups as well as... 

The classical Zeisel method for the determination of ether (59) consists of digesting the substrate with hydrogen iodide. Analysis shows that the reaction proceeds in a favorable manner as designated by Saville. Sulfides do not interfere with the determination because the hard-soft combination is incorrect in such cases. 

The level of alcohol obtained during the exchange reaction of acrylamide is correlated with data obtained using Zeisel cleavage of the alkoxy groups. These data are summarised in Table 3.9. Comparable results are obtained using both... 

Zeisel s method is used to determinate methoxy and ethoxy groups. It is a method of both qualitative and quantitative organic analysis. It is mentioned under the heading General Methods of Analysis of the 10th edition of the french pharmacopeia. It ends with an argentometric titration. Its principle is based on the reaction of hydroiodic acid (Berthelot s universal reductor) with ether oxides, according to the reactions... 

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