NOTES ON SCIENTIFIC RESEARCH. 129 
Hydrocarbons. 
Camphene. We mentioned on p. 133 of our Report of October 1913 that 
P. Lipp had succeeded in identifying nitrocamphene as a true nitro-body. The same 
author’) has recently studied the action of strong mineral acids upon this compound. 
It was already known that when the nitro-body is dissolved in concentrated sulphuric 
acid, and the suitably diluted sulphuric solution is boiled, tricyclenic acid results”). 
Another conversion has been observed by May*) when treating the body with aqueous 
fuming hydrobromic acid. This reaction afforded a body CioHi; NOBr2, which was 
reduced without difficulty to CioHisN. 
In the first-named reaction the nitrogen is eliminated in the form of hydroxylamine. 
Hence, Lipp assumes that a hydroxamic acid is formed as an intermediary product. 
Nevertheless the first intermediary product which could be isolated was not a hydroxamic 
acid, but the neutral sulphuric ester (I) of a hydroxyhydroxamic acid, possessing the 
constitution CipHi;O;NS. This sulphuric ester is readily saponifiable and then affords 
the basic hydroxyhydroxamic acid (II), which when warmed in a sulphuric acid solution 
readily splits up into tricyclenic acid (IV) and hydroxylamine. The hydroxyhydroxamic 
acid does not belong to the camphene series, but to the camphane series, for with 
nitrous acid its nitrogen was split off in the form of nitrous oxide, giving rise to a 
hydroxy acid (III), which proved to be identical with the hydroxyapocamphane car- 
boxylic acid described by Bredt and May‘). Seeing that it is highly improbable that 
an interchange of systems should take place when nitrous acid is allowed to react 
upon the hydroxyhydroxamic acid, the interchange must occur at an earlier stage, when 
sulphuric acid is absorbed by the double bond of nitrocamphene (V). Hence the 
hydroxyhydroxamic acid is not camphenylhydroxamic acid, as Lipp formerly believed 
it to be, but a 2-hydroxyapocamphanehydroxamic acid. 
The action of hydrobromic acid is altogether different from that of sulphuric acid. 
In this case hydrobromic acid is first absorbed, the absorption being connected with 
the conversion from the camphene- to the camphane-series. Next, the nitro-group is 
converted into the hydroxamic acid form, while at the same time one hydroxyl is 
replaced by bromine. The 2-bromoapocamphanehydroximic acid bromide (VI) which 
corresponds to the sulphuric ester mentioned above, is much more stable than the 
latter. The functions of the two bromine atoms differ completely. The first is readily 
replaced by reacting with ammonia or aniline in ethereal solution, affording 2-bromo- 
apocamphaneamide oxime and anilide oxime. The second bromine atom is more 
closely combined, but can be detached by boiling bromoapocamphane amide oxime 
with water, when hydroxyl is substituted for it. When the bromide is treated with 
methylalcoholic potash both the bromine atoms are exchanged for methoxyl, giving 
rise to 2-methoxyapocamphane methyl hydroxamate, which is split up into tricyclenic 
cid and hydroxylamine by boiling it for a short time with sulphuric acid. The 
body CioHi;N, which had already been prepared by May from bromoapocamphane 
hydroximic acid bromide by reducing it with zinc dust and glacial acetic acid 
represents the nitrile of apocamphane carboxylic acid (VII). This conclusively shows 
that the bromide belongs to the camphane series. The reduction of a hydroximic 
acid halogenide into the nitrile of the corresponding carboxylic acid appears to be 
a novel proceeding. 
1) Liebigs Annalen 402 (1914), 343. — %) Bredt and May. Chem. Ztg. 33 (1909), 1205; Report April 1910, 
179. — %) Dissertation. Aix-la-Chapelle 1910, p.65. — +) Chem. Ztg. 84 (1910), 65; Report April 1910, 180. 
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