The reaction of meta-and para-xylylene diamine with a crown ether tetracarboxylic acid chloride gives macrotricylic tetra amide hosts in high yield. A similar reaction of diamines with the related bis-anhydride gives bicyclic diamide/diacid hosts.
Crown ethers derived from (+)-tartaric acid, such as the tetracarboxylic acid from two equivalents of RR-(+)tartaric acid (l), have been widely exploited as frameworks for the construction of specific complexing agents and other biomimetic models of catalysis and transport (1). The carboxylate groups provide an easy synthetic entry to a wide range of derivatives (2-6) which possess well defined conformations with carboxylate derived groups in axial positions on the macrocycle (7-l 1). The derivatives form stable complexes with a range of inorganic and organic cations through direct interaction with the crown ether cavity and lateral interactions with the side chains (2,3,6-l 1). Although the majority of known derivatives possess a single macrocyclic unit, a limited number of macmpolycyclic structures incorporating the tartro-crown ether unit have heen reported (12-15). Relatively little is known about the complexation chemistry of these macropolycyclic hosts, but higher levels of discrimination would be expected in the selective binding of guests due to the greater level of preorganization of the host (16).
Investigation of the complexation processes of these and related macropolycyclic hosts will require a more direct synthesis than the methods reported to date (12)(13)(14)(15). This paper reports our recent approaches to macropolycyclic structums derived from tartro crown ethers based on the direct reaction of diamines with crown ether acid chlorides and anhydrides. The general reaction scheme is illustrated below.