| abstract |
MACROCYCLIC POLYETHER "CROWN" COMPOUNDS CONSISTING OF OXYGEN ATOMS JOINED TO ADJOINING OXYGEN ATOMS BY CHAINS OF FROM 2 TO 3 CARBON ATOMS TO FORM A POLYETHER RING HAVING FROM 15 TO 30 ATOMS IN THE RING. RING CARBON ATOMS CAN BE C1-C4 ALKYL SUBSTITUTED. THE CROWN COMPOUNDS ARE PREPARED BY RING CLOSURE OF HALO-POLYETHERALCOHOL COMPOUNDS WITH, E.G., SODIUM HYDRIDE OR POTASSIUM T-BUTOXIDE ACCORDING TO THE WILLIAMSON SYNTHESIS. CROWN COMPOUNDS SO PREPARED FORM COMPLEXES WITH A WIDE VARIETY OF IONIC METAL COMPOUNDS, ESPECIALLY THOSE OF ALKALI METALS AND ALKALINE EARTH METALS, MAKING IT POSSIBLE TO USE CERTAIN CHEMICAL REAGENTS IN MEDIA WHEREIN THEY ARE NORMALLY INSOLUBLE. |