— 144 — 



n D 1,44962; disemicarbazone, m. p. 183 ) was formed; with potassium 

 permanganate, a methyl keto acidC 10 H 18 O 3 (b.p. 174 toi8o°at 9 mm. 

 pressure; d2o° i>o i( 3; n D i j45°62; mol. refr. found 49,62, calculated 

 for C 10 H 18 O 3 50,02). This shows that the dihydroterpinene is identical 

 with carvomenthene which Semmler 1 ) had previously obtained by 

 the reduction of limonene monohydrochloride and of phellandrene. 

 In the author's opinion, a re-arrangement must for this reason take 

 place in the production of the monohydrochloride from sabinene, inas- 

 much as intermediarily a dichloride is formed, from which HC1 is 

 immediately split off, as is expressed in the following formulae: — 



/CH 2 -CH 2 /CH 2 -CH 2 /CH 2 -CH 2 



CH -C ^>C.C q H 7 -->CH q .CCl \cCl.QH 7 ->CH q .C NcCl-CH, 



2 ^^/ 3 7 3 / 3, 8 / 37 



X CH-CH 2 X CH 2 -CH 2 X CH-CH 2 



Sabinene Intermediary product Monochloride 



/CH 2 .CH 2 /CH 2 .CH 2 



-> CH 3 .C ^CH.C 3 H 7 ~> CH 3 .CO ^>CH.C 3 H 7 



XH-CH 2 CHO-CH 2 



(CO.OH) 



Dihydroterpinene Keto aldehyde (or acid) 



As the monochloride can readily be converted into the dichloride, 

 and the latter further into terpinene 2 ), Semmler follows up the 

 description of the above-named experiments with a theoretical con- 

 templation regarding the formula of terpinene, in which he arrives at 

 the result that the following constitution must be ascribed to this 

 hydrocarbon : — 



CH 2 C H 



H 3 Cc/ ScC 3 H 7 . 



CH CH 2 



Similar to the formation of the monochloride from sabinene, he 

 also imagines the conversion of camphene into isobornylchloride, and 

 of pinene into bornylcliloride. One molecule HC1 attaches itself to 

 the bridge-bond, -with ring-disruption, whilst a second molecule HC1 

 becomes attached to the double-bond, and immediately becomes 

 liberated again, with formation of a new double-bond (or new ring). 



On oxidising sabinene with potassium permanganate, Semmler 

 obtained, in addition to the previously described a-hydroxy acid, an 



x ) Berl. Berichte 36 (1903), 1035 and 1753; Report October 1903, 83. 

 2 ) Ibidem 40 (1907), 588; Report April 1907, 141. 



