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1,8-Bis(9'-carbazolyl)-3,6-dioxaoctane: Synthesis and structure
Authors: V.G. Shtamburg, R.I. Zubatyuk, V.V. Shtamburg, S.V. Kravchenko, B.V. Uspensky, E.A. Klots, A.V. Mazepa
Number of views: 411
The most common phase transfer catalysts are known to be crown-esters, cryptands, quaternary ammonia salts and podands. The podand kind of phase transfer catalysts is the most efficient in chemical technology of organic substances. The aim of this investigation is the syntheses of new podand containing two carbazole cycles and triethylene glycol chain. The method of the synthesis of 1,8-bis(9'-carbazolyl)-3,6-dioxaoctane has been developed. This podand containing two carbazolyl groups is stable in alkaline media. The reaction of the synthesis is carried out in the 1,4-dioxane solution. Carbazole reacts with an excess of potassium hydroxide in the boiling solvent in the presence of tetrabutyl ammonium bromide. Then the hot solution of potassium salt of carbazole is filtered off. Subsequently, the reaction of potassium salt of carbazole with 1,8-dibromo-3,6-dioxaoctane is carried out in 1,4-dioxane solution. After boiling the reaction mixture is cooled. The obtaining potassium bromide is filtered off. The 1,4-dioxane was removed by vacuum. The residue is washed with water and dried at a reduced pressure. The product is extracted by boiling carbon tetrachloride. After evaporating the solvent the crude product is obtained with a yield of 77%. The solid residue is crystallized from benzene or ethanol yielding the pure product. The additional quantity of the product can be obtained by column chromatography of the remaining filtrate. The overall yield of pure 1,8-bis(9'-carbazolyl)-3,6-dioxaoctane is 54 %. The structure of the obtained compound has been confirmed by NMR 1H spectra, NMR 13C spectra, mass-spectra and XRD study.