DICYCLOHEXYL-18-CROWN-6-POLYETHER

DIAZACYCLOOCTADECANE, 54, 88 MACROCYCLIC POLYETHERS DIBEN-ZO—18-CROWN-6-POLYETHER AND DICYCLOHEXYL- 18-CROWN-6-POLYETHER, 52, 66 Malonaldehyde bis(diethyl acetal), 52, 139... 

Potassium acetate complex with dicyclohexyl-18-crown-6-polyether, 52, 71 Potassium amide, 52, 75 Potassium azide, 50, 10 Potassium tert-butoxide, 52,... 

Dicyclohexyl-18-crown-6 polyether possesses unusual physiological properties which require care in its handling. It is likely that other cyclic polyethers with similar (iomplcxing power are also toxic, and should be handled with ccpml care. 

This residue is a mixture of stereoisomerio dicyclohexyl-18-crown-6 polyethers which may be contaminated with some unchanged dibenzo-18-crown-6 polyether and with alcohols arising from hydrogenolysis of the polyether ring. The submitter reports that this residue is sufficiently pure for many purposes such as the preparation of complexes with potassium hydroxide which are soluble in aromatic hydrocarbons. 

Skin absorption. Dicyclohexyl-18-crown-6 polyether is very readily absorbed through the skin of test animals. It caused fatality when absorbed at the level of 130 mg./kg. 

The checkers prepared a crystalline complex of potassium acetate with isomer B of dicyclohexyl-18-crown-6 polyether by the following procedure. To a stirred solution of 15.0 g. (0.0404 mole) of dicyclohexyl-18-crown-6 polyether (mixture of isomers) in 50 ml. of methanol was added a solution of 5.88 g. (0.0600 mole) of anhydrous potassium acetate (dried at 100° under reduced pressure) in 35 ml. of methanol. The resulting solution was concentrated under reduced pressure with a rotary evaporator, and the residual white solid was extracted with 35 ml. of boiling methylene chloride. The resulting mixture was filtered and the filtrate was cooled in a dry ice-acetone bath and slowly diluted with petroleum ether (b.p. 30-60°, approximately 200 ml. was required) to initiate crystallization. The... 

The physical properties of many macrocyclic polyethers and their salt complexes have been already described. - Dibenzo-18-crown-6 polyether is useful for the preparation of sharpmelting salt complexes. Dicyclohexyl-18-crown-6 polyether has the convenient property of solubilizing sodium and potassium salts in aprotic solvents, as exemplified by the formation of a toluene solution of the potassium hydroxide complex (Note 13). Crystals of potassium permanganate, potassium Lbutoxide, and potassium palladium(II) tetrachloride (PdClj + KCl) can be made to dissolve in liquid aromatic hydrocarbons merely by adding dicyclohexyl-18-crown-6 polyether. The solubilizing power of the saturated macrocyclic polyethers permits ionic reactions to occur in aprotic media. It is expected that this [)ropcrty will find practical use in catalysis, enhancement of... 

There are now several structural studies on cobalt(II) crown ether and cryptand complexes (Table 78), which show the coordination mode to be markedly sensitive to the macrocycle cavity diameter. Both 12-crown-4 and 15-crown-5 (cavity diameters 120-150 pm and 170-220 pm respectively) can include ions to form structures in which every ether oxygen atom is bound to the metal. In contrast Co—O (ether) bonding is destabilized in the larger 18-crown-6 and dicyclohexyl-18-crown 6 polyethers. In the blue complexes obtained from the reaction of these compounds with C0CI2 the role of the cyclic polyether is to solvate discrete [Co(H20)6] cations and [CoC ] " anions and there are no direct Co—O (ether) bonds.A similar effect is seen in the Co" complex of a 27-membered-ring macrocycle where the pentacoordinate structure (267) features only one long Co—O (ether) bond. " ... 

C-allylation of PhO" Na with H2C=CHCH2C1 in a variety of solvents in the presence of different crown ethers is most effective in each case when using poly(vinylbenzo-15-crown-5)polyether. Only in the presence of the crown ethers 15-crown-5 and 18-crown-6 are the anions in potassium phthalimide and sodium saccharinate, respectively, sufficiently activated to bring about nucleophilic aromatic substitution of the 4-fluorine in pentafluoropyridine. The formation of 2,4-dinitrophenol, in addition to the expected ether, from 2,4-dinitrochlorobenzene and potassium 2-propoxide in 2-propanol-benzene (1 1), in the presence of dicyclohexyl-18-crown-6 polyether, has been accounted for on the basis of a nucleophile-radical reaction (5rn1)/ ... 

Pedersen, C.J. Macrocyclic polyethers. Dibenzo-18-crown-6 polyether and dicyclohexyl-18-crown-6 polyether. Org. Synth. 1972, 52. 66-74. 

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