NEW MACROCYCLIC LIGANDS .7. THE SYNTHESIS OF MIXED-DONOR SPIRO-LINKEDMACROCYCLES

The syntheses of five new spiro-linked bis-macrocyles, incorporating f our ether oxygen and four or six secondary nitrogen heteroatoms, are r eported. Two strategies were employed-the first involved the condensat ion of a spiro tetraaldehyde with 2 equiv. of ethane-1,2-diamine or pr opane-1,3-diamine or 2,2'-diaminodiethylamine followed by in situ redu ction of the resulting intermediate tetraimines. The second procedure began with pentaerythrityl tetraamine [C(CH2NH2)(4)] which was then co ndensed with 2 equiv. of a dialdehyde moiety in which two ether oxygen atoms, bridged by either two or three methylene groups, were incorpor ated in its backbone. A related in situ reduction step to that employe d in the first procedure then yielded the required double-ring macrocy cles. For use in comparative studies, the corresponding single-ring ma crocycles were also synthesized where they had not been reported previ ously.