The manner in which the rate of removal of halogen from halogenated benzenoid derivatives is governed by atoms or groups of atoms which repress reactivity

Abstract

1. Investigations have been carried out with a view to discovering to what extent the influence of the oxygen atom in p-cresol is neutralised by (a) a (>C=0) group, (b) a (NO₂) group, (c) a Br atom, when the two latter are situated at some distance from this oxygen atom.2. Advantage has been taken of the fact that there is a close connection between the ease of removal of halogen from compounds containing a CH .Hal.group and direct substitution in the benzene nucleus to which this .group is attached.3. The alkaline hydrolysis of the nitrobenzylbromides gives an abnormal result because of the production of a secondary reaction. This was not observed in the case of the w-bromotoluicacids.4. It has been shown that the conversion of the nitrogen atom in an amino group to one which has a positive charge in a substituted amino group prevents the removal of an iodine atom from any position in the nucleus to which the nitrogen is attached.5. It has been shown that a (>C=0) group directly attached to a benzylchloride molecule represses the ease of removal of the halogen atom very markedly.6. An attempt has been made to explain all the phenomena observed from the standpoint of the recent theories on reactivity in an organic molecule.