print pageprinter friendly
Reports: UNI152318-UNI1: The Synthesis of C4 Symmetric Oxacalix[4]arenes and Related Macrocycles

Jay Wm. Wackerly, PhD, Central College

The synthesis of many of the molecules originally proposed (e.g., synthesis of 1 and 2) have not worked out to date.  We are still pursuing our main goal of accessing a C4 symmetric oxacalixarene (1) our lab’s current focus of research has come from our attempts to synthesize 2.  Attempts to repeat substitution reactions on haloquinones (e.g., 3) with phenoxides did not proceed to the desired product as previously reported.  However, when we explored an analogous quinone (DCNQ) that contained no hydrogen substituents we were able to get substitution in good yields (e.g., 4-6). 

Based on these results we were able to make modifications to the diphenol in order to obtain macrocycle 7 in good yields as previously reported.  This year we substantially improved the yield on the large scale synthesis (>1 g) and have begun to study the host-guest binding of 7 with pyridine-N-oxide guests.  Preliminary data indicates a 1:1 binding ratio with good binding constants for a guest that is only bound electrostatically and competes with the solvent for binding. Building on the use of DTBR as a monomer for the synthesis of 7, other oxacyclophanes have been synthesized utilizing other electrophiles under similar conditions (purple). 

While exploring substitution reactions of DCNQ with nitrogen nucleophiles we have gained insight some stark differences in reactivity (green).  One example of this difference is that high yields of product 8 can be obtained when diamine nucleophiles are reacted with hydroxynapthoquinones under acidic conditions.

This research was highlighted this past year in a talk and five undergraduate research posters at the Joint 41st Great Lakes and 46th Central Regional Meeting of the American Chemical Society, Grand Rapids, MI, May 27-30, 2015.  Additionally, the second graduate from our lab, who was supported by this PRF grant in the previous year, is currently an organic chemistry graduate student at Northwestern University.