Synthesis of Lipophilic 18-Crown-6 Diacids for the Membrane Transport of Alkaline-Earth Cations

Article abstract of DOI:10.1021/jo00179a004

The synthesis of three different types of lipophilic 18-crown-6 diacids is described.A didecyl crown ether 2,3-diacid (1) was prepared as a minor product from a diiodide precursor (12) and threo-11,12-docosanediol by thallous ethoxide cyclization.The major nonpolymeric products resulted from elimination followed by cyclization to give 15-crown-5-derivatives.A crown ether 11,12-diamide 2,3-diacid (4) was prepared by a similar route involving cyclization of a benzyl protected precursor (26) and N,N,N',N'-tetramethyltartaramide (9).Isomeric syn and anti 2,11(12)-diamide 3,12(11)-diacid derivatives 6 and 7 were prepared from the known crown ether bisanhydride 8 and alkylamines.The product mixture was separated by chromatography, and the isomers were identified by comparison of acidity and stability constants for complexation with those of closely related syn/anti crown ether acids.