The behaviour of m-and p-fluorotoluene in Friedel-Crafts acylations has been studied. With the former, the reaction is rigidly proved to involve the position para to the fluorine atom, and with the latter, the ketone groups are assumed by analogy to occupy the position ortho to fluorine. Numerous other aromatic and heterocyclic fluorine-containing compounds have been prepared. in-CHLORO-and? zz-BROMO-TOLC'ESE undergo acetylation (Clam, J. pr ...