FORMATION AND CHARACTERIZATION OF DELTA-5,6/5',6'-UNSATURATED DISTERYL ETHERS

The formation of disteryl ethers at 200°C in the presence of anhydrous copper sulfate was studied using saturated, Δ5,6-unsaturated, and 4-methyl sterols, i.e. 5α- and 5β-cholestan-3β-ol, cholesterol, epicholesterol, campesterol, sitosterol, stigmasterol, and lanosterol. Disteryl ethers arise as minor reaction products from 3β-hydroxy Δ5-sterols, whereas all other sterols form elimination products exclusively. 1H- and 13C-NMR spectra as well as 1H/NMR COSY, 1H/13C-NMR HETCOR, attached proton test (APT) spectra and mass spectra of dicholesteryl ether, disitosteryl ether, distigmasteryl ether, and dicampesteryl ether, are described. Characterization of individual disteryl ethers by spectroscopic methods is of particular interest with regard to the identification of these substances as markers of industrial bleaching of fats and oils. © 1990.