The Limonene Group of Ter penes. 
343 
their weight of'ether. These solutions are strongly optically active 
[u] D =+313.4° resp.—314.8° 13 . The dipentene derivative is more read¬ 
ily soluble, and is optically inactive. 
/ 3-Nitrosochlorides. 
The limonene /3-nitrosochlorides are precipitated from their chloroform 
solutions with methyl alcohol as woolly crystalline needles. 14 By care¬ 
ful crystallization from chloroform they can be obtained in handsome 
prismatic crystals. 15 The /?-nitrosochlorides are much less soluble than 
the ar-derivatives. Their optical activity is also not as great: [a jp __ 
+ 240.3° resp.— 242.2° 16 The melting point has been found to vary, viz., 
100-106° 14 Dipentene /3-nitrosochloride, like the u-derivative, is more 
Soluble, does not crystallize as well as its optically active modifications 
and melts at 101°- A third modification which melts at 75-76° has been 
observed. 17 
Chemical Properties. 
The chemical properties of the a- and /3-nitrosochlorides do not differ 
essentially and can, therefore, be considered together. When carefully 
heated by themselves (Tilden 3 ), or when heated with alcoholic potassa 
(Wallach 18 ) hydrogen chloride is split off and carvoximes result (Comp, 
also Goldschmidt 5 ). Thus dextrogyrate limonene-nitrosochloride yields 
laevogyrate carvoxime, also obtainable from laevogyrate carvol; whereas 
laevogyrate limonene nitrosocloride yields dextrogyrate carvoxime, also 
obtainable from dextrogyrate carvol. 19 From dipentene nitrosochloride 
optically inactive carvoxime results, which can also be obtained by 
mixing solutions of equal parts of the optically active carvoximes. 20 
A molecule of hydrogenchloride can be added to form nitrosochloride- 
hydrochlorides, but these differ from the hydroehlor-nitrosochlorides. 21 
The chlorine of the j group can easily be replaced by basic radicles 
whereby nitrolamine bases result. In these double decompositions a- 
and /3-nitrosochloride behave alike. 22 
The nitrosochlorides are unsaturated. With bromine they yield an 
unstable dibromide (Tilden 1 ). Their unsaturated condition is also 
recognizable from the hydrochlor nitrosochloride. 
Nitrosates. 
Thus far dipentene-nitrosate only has been described. There appears 
to be some difficulty connected with the preparation of the limonene- 
nitrosates. 23 Dipentene-nitrosate crystallizes in laminae which melt at 
84° In its constitution it is analogous to the nitrosochloride; by split¬ 
ting off nitric acid o-carvoxime results; by double decomposition with 
bases the optically inactive nitrolamine base results; apparently it adds 
