Hydrogen bromide, viii

Dihydro-i/< -codeinone is obtained in 40 per cent, yield by the Oppenauer oxidation of dihydroallo-with phosphorus pentachloride gives 8-chloro- and 1 8-dichlorodihydrocodide, which are also produced in the same way from dihydro-i/ -codeine-A thionyl chloride effects chlorination in the aromatic nucleus only. With phosphorus tribromide it apparently suffers replacement of the hydroxyl group by bromine, loss of hydrogen bromide, and demethylation, as the product is desoxymorphine-D [240] (see Chap. VIII). 

The hitherto-synthesized derivatives are substituted on the nitrogen, with the exception of the hydrogen bromide adducts VIII of thiocyanates which have recently been synthesized by Allenstein and Quis ( ). 

The reaction of cyanogen-di-N-oxide (VIII) with hydrogen bromide in glacial acetic acid has been used as a quantitative analytical method ( ), and aqueous hydrochloric or hydrobromic acid can be added to afford the corresponding dihalide (IX)... 

In order to find out what R+ is, we consider first the common experience that when a tert- mty halide is treated with an aluminium halide under ordinary conditions, there is a brisk evolution of hydrogen halide and a coloured solution containing oligo-isobutylenes and condensed allylic ions is formed. In the present experiments the solutions were colourless, no hydrogen halide was evolved, and the conductivity was stable and behaved reversibly. Further, the rectilinearity of the k-[A1X3] plots in Figures 9 and 10, and the smallness of the intercepts on the K-axis, showed that ions generated by reactions other than those of type (viii) must have been very scarce, and for the experiment with tert-butyl bromide this was borne out by the absence of any byproducts. 

Thus reaction with alkyl halides such as allyl bromide or pro-pargyl bromide allow for the introduction of oleflnlc2. . or acetylenic side groups onto the phosphazene ring VI, while alcohol leads to the formation of hydrido-phosphazene complexes VII. The hydrogen in these compounds can be replaced with halogen to yield the first series of iodor-phosphazene compounds VIII. 

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