The action of halogens upon the arylazoacetoacetates and related compounds.—Part II

It has recently been shown that the action of halogens upon the arylazoacetoacetates is not so simple as was formerly supposed, but varies according to the experimental conditions. When the nucleus is already fully substituted, halogen atoms may enter or replace the acetyl group, and may even, in some cases, replace the carbethoxy group. For example, the following compounds were obtained by the action of bromine upon ethyl 2: 4: 6-tribromophenyl-azoacetoacetate. The more energetic action of chlorine upon ethyl 2: 4: 6-trichlorophenylazoacetoacetate, although it yields stages (I) and (II) at the ordinary temperature, causes breaking down of the molecule when the higher temperature, which would be necessary to bring about stages (III) and (IV), is employed.