The thermal elimination of iodine from some substituted α-iodonaphthalenes: a structural study

Abstract

Brief heating of a number of methyl 8-iodo-5,7-dimethoxy-2-naphthoate derivatives with a variety of added hydroxy-, methoxy-, or acetoxy-substituents in the 4- and 6-positions has been found to result in facile elimination of iodine in certain compounds but not others; subsequent examination of other aspects of the chemistry of the system have suggested this to be a solid state effect. Single crystal X-ray structure determinations have been carried out on a representative selection of compounds, suggesting that in those examples where elimination has been found to occur, intimate charge-transfer interactions between the conjugated systems of adjacent molecules arising from the nature of the crystal packing are responsible; in those compounds which do not eliminate iodine, similar interactions may also be found but are associated with substituent out-of-plane steric interactions which hinder relative movement of the naphthalene moieties in the lattice.