Tetraethylene glycol ditosylate

Greene reported the preparation of monoaza-18-crown-6 (i) in 1972. His approach was direct, involving condensation of N-trityldiethanolamine with tetraethylene glycol ditosylate. Removal of the protecting group could be achieved by acid cleavage. Unfortunately, neither details of the synthesis nor physical properties were included in this report. 

The synthesis of 1 was accomplished by stirring N-benzyldiethanolamine in the presence of NaH/DMF and tetraethylene glycol ditosylate at 25 °C for 48 h. After chromatography, N-benzyl-7 was isolated in 25% yield as a yellow oil. Debenzylation (Hj/Pd)... 

Prepare a solution of sodium hydroxide (40 g, 1 mol) in distilled water (200 mL) and cool to room temperature. Place the solution in a 2L two-necked round-bottomed flask fitted with a thermometer and add a solution of tetraethylene glycol (68 g, 60 mL, 0.35 mol) in THF (200 mL) while stirring. Put the flask in an ice bath and cool to 0 °C. Place a solution of p-toluenesulphonyl chloride (145 g, 0.76 mol) in THF (200 mL) in a pressure-equalized addition funnel and add dropwise to the stirred glycol solution over 3 h or so. Carefully monitor the temperature of the solution and keep below 5 °C throughout. Once the addition of the p-toluene-sulphonyl chloride solution is complete, continue to stir the solution for a further 1 h at below 5 °C. Pour onto a mixture of ice and water (250 g/250 mL) and continue to stir. When all the ice has melted, remove most of the THF by rotary evaporation and extract the product into dichloromethane (3 x 100 mL). Dry the dichloromethane extract over calcium chloride, filter and remove the solvent by rotary evaporation. The product, tetraethylene glycol ditosylate (3), is obtained as a colourless oil. 

Stir at 40 °C in a 1 L three-necked round-bottomed flask, fitted with a pressure-equalized addition funnel and a thermometer, until a clear solution is obtained. Add a solution of tetraethylene glycol ditosylate, 3, (49 mL, 60.5 g, 0.12 mol) in dry 1,4-dioxane (180 mL) dropwise over 2 h from the addition funnel. Once all the ditosylate has been added continue to stir for a further 2 h and allow the solution to cool to room temperature. 

Tetraethylene glycol ditosylate (3) f-Butanol [FLAMMABLE] Potassium f-butoxide [CORROSIVE ... 

Tetraethylene glycol Tetraethylene glycol ditosylate Tetrahydrofuran... 

Reaction of calix[4]arene 1 with tetraethylene glycol ditosylate (8) gave calixcrown ether... 

The reaction of calix[4]arene 9b with tetraethylene glycol ditosylate gave the caUxerown ether 25 in 53 % yield [24]. Subsequent alkylation afforded the 2,4-di-alkylated calixcrowns 26 in mixtures of the cone, the partial cone and in some cases the 1,3-altemate conformations, except for the dimethyl ether 26a, which is flexible and adopts the cone conformation. These alkylated calixerown ethers form complexes with alkali metal ions and all of them are selective for K+. The partial cone is not only the best conformation for complexation, which was nicely illustrated by compound 26a, which changed from a cone to a partial cone conformation upon complexation of a cation, but also shows the highest selectivity for K . The dinriethyl ether has been applied in a K -selective electrode based on ISFET-technology [25] and in supported liquid membranes that are used for the selective transport of K [26]. 

Subsequent to these results, we discovered a striking example of the formation of a double calixcrown by changing the stoichiometry of the reactants, p-tert-Butylcalix[4]arene was treated with a 15 equivalent excess of tetraethylene glycol ditosylate to afford double p-terr-butylcalix[4]-few-crown-5 15 in which each calixarene unit is in the 1,3-altemate conformation and 1,3-capped by a tetraethylene glycolic chain [21]. 

As a part of our work on the synthesis of double calixcrown ethers [5], we reacted calix[4]arene with tetraethylene glycol ditosylate in the presence of cesium carbonate instead of potassium carbonate. Surprisingly, we isolated the l,2-calix[4]arene-fcw-crown-5 (3). Calixaiene (3) was deduced to be in the cone conformation from spectroscopic data. This conformation was ascertained by X-ray diffractometry. Preliminary metal binding properties of ligand (3) were anticipated by modeling with molecular mechanics. 

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