Halogen Substituted 1,3‐Cyclohexanediones II. New Chlorinated Cycloalkanones from 2, 2‐Dichlorodimedone

A number of new substances obtained from 2,2‐dichlorodimedone are described. The most interesting features of the reactions are: a) the ring contraction to a 2‐cyclopentenone derivative with simultaneous carbon monoxide elimination, b) the isomerization procedure of halogenated ketones in dimethylformamide and hydrogen chloride, c)the aromatization to some new resorcinol derivatives. The high yields give most of the procedures a distinct preparative interest.