The Synthesis and NMR Study of N6', N9-Octa-methylenepurine Cyclophane

Abstract

<p>N6', N9-Octamethylenepurine cyclophane was synthesized to act as a ¹H NMR probe for the study of the diamagnetic anisotropy about the adenine system. The title compound was formed from 6-chloropurine and cyclooctanone using two variations of the same general approach. The ¹H NMR studies resulted in the assignment and identification of each proton resonance. As a method of confirming the assignments, nuclear Overhauser enhancement studies as well as conformational analysis using X-ray crystallography were completed. Upon correlation of the proton magnetic resonance spectrum with the structure of the title compound, an attempt was made to use a model calculation to determine the diamagnetic shielding anisotropy of adenine by comparison with the methylene proton chemical shifts. Finally, in an effort to further characterize the diamagnetic shielding anisotropy about adenine, a homolog to the title compound, N6',N9-Nonamethylenepurine cyclophane, was synthesized.</p>