Abstract
The introductory section deals with modern views on the nature substitution in the benzone nucleus and on the mechanisms whereby substituents exert their influences upon the nucleus. These ideas, mainly due to Ingold and Robinson, are applied to the naphthalone molecule. Arguments put forward for the symmetrical structure of maphthalene are discussed and the differences in chemical and physical properties of 1-bromo- and 3-bromo-b-naphthylamines provide evidence for a symmetrical structure. Substitution of naphthalene is compared with and shown to be closely nua-logous to substitution of diphenyl. The directive powers of the hydroxyl and derived substituents are shown to fall off in the order oh>or>osos2h. 4-nitro-alpha-naphthylamine, like-alpha-naphthylamine, is shown to be capable of direct bromination, but can also give 2:4-dibromo-l-naphthalonediazoperbromide and the mechanism for this re-action is discussed. The directing power of the acetamide substituent is discussed and the o/p ratio derived from the nitration of alpha-acet-naphthalide. Nitration experiments show the arylaulphonomide group to be far more powerfully orienting than the restamide group and comparable in reactivity to the phonolic subatituent. A marked difference between bromination and nitration of alpha-sulphon-naphthalides is observed but there is no such difference in the case of b-naphthalides. In these respects alpha-sulphon-naphthalides are closely analogous to 2-sulphonamido diphenyls and b-naphthalides analogous to 4-sulphonaside diphenyls. The difficulty with which alpha-naphthalides undergo bremination in the 3-position is shown by comparison with the substitution of disulphonamide derivativos of m-phonyleuediamine not to be due to steric factors. The disulphosamide substitutent is shown to have a far smaller orienting influence that either the acetimide or sulphonamide groups both in the benzene and the naplithalene series. Substitution in 1:5-amino naphthol proceeds normally: a feebly orienting group in one ring does not modify nomitions of substitution due to a powerfully orienting group in the other ring. Electronic principles applied to the symmetrical structure of the naphrthalene molecule supply a fairly consistent basis for the interpretation of substitution processes in the naphthalene molecule.