Synthesis and Properties of Ligands Based on Benzoquinoline

Article abstract of DOI:10.1021/jo00083a024

The preparation of 3-amino-2-naphthaldehyde is described.Ammonolysis of 3-hydroxy-2-naphthoic acid affords the corresponding amino acid which can be esterified and then reduced with LAH.Protection of the amino group, MnO2 oxidation of the primary alcohol to an aldehyde, and deprotection gave the amino aldehyde which is an excellent Friedlaender synthon for benzoquinolines.Dimethylene-bridged analogues of 2,2'-bipyridine and 2,2';6,2''-terpyridine were prepared as well as orthocyclophanes derived from tetracyclo<6.3.0.0^4,11.0^5,9>undecane-2,7-dione (TCU-2,7-dione).The absorption and emission spectra of these species are consistent with the parent benzoquinoline where bathochromic shifts result from increased delocalization.The TCU derivative evidences exciplex formation so that its benzoquinoline emission is almost completely quenched and an exciplex emission appears at 525 nm.Electrochemical analysis indicates that both reduction and UV absorption involve the same ?^* orbital.