Some uses of the hydrohalides of organic bases and their halogen addition compounds.

The Thesis is in two parts. Part I describes some partially successful attempts to develop satisfactory halogenating agents for the substitution of chlorine and bromine in organic compounds, especially carbonyl compounds, by the employment of the chlorine and bromine addition compounds of pyridine hydro-chloride. The use of the halogeneted carbonyl compounds for the synthesis of 2-mercaptothiazoles and of aneurin chlorine hydrochloride, is aIso outlined. The application of the bromine-containing reagent to the addition of bromine to carbon-carbon double bonds gives an insight into the uncertain composition of this reagent, due to halogen interchange, and various analytical investigations of its constitution are described. The usefulness of pyridine hydrobromide cibromide as a convenient carrier of "active" bromine is confirmed. Part II describes the reaction of certain esters with the hydrohalides of heterocyclic tertiary bases. Such hydro-halides have recently been employed for the fission of phenolic ethers and it is now shown that, by their use, "alkyl-oxygen" fission may be produced in esters of substituted malonic, cyanoacetic and acetoaoetic acids; decarboxylation, of the unstable acids produced yields substituted acetic esters, acetonitriles and methyl ketones respectively, the overall reaction constituting "de-carbetlioxylation". Attempts to improve the experimental technique of such reactions are also described