— 166 — 



The reduction of sabinene leads to dihydrosabinene, Ci Hi 8 : b. p. 

 156 to 157°, d 20o 0,8120, « D — 2°2', n D20O 1,4484, mol. refr. calc. as 

 CioHis/^ 45,63, found 45,54. 



W. Ipatieff 1 ) also has recently investigated the reduction of hydro- 

 aromatic hydrocarbons. He reduced limonene [«]75,50 O2 ), by passing 

 hydrogen into it under pressure, in the presence of oxide of copper or 

 reduced copper. The use of reduced copper has the advantage of 

 enabling the experiment to be conducted at low temperatures. Apparently 

 the reduction is at first limited to the addition of hydrogen to the double 

 bond in the aliphatic chain; afterwards a second molecule of hydrogen 

 is absorbed, with formation of menthane. 



The experiments were extended to l-«-pinene, from French oil of tur- 

 pentine. Iron and copper oxide were selected as catalysing agents and 

 the hydrogen was forced in at a pressure of up to 110 to 112 atmospheres. 

 No reduction was obtained with the iron, but with copper the experiment 

 was successful, the result being a hydrocarbon of which the analytical 

 values corresponded tolerably well to the menthane formula. But the re- 

 action product was not uniform, inasmuch as it was attacked by per- 

 manganate of potassium, and was also rather strongly affected by ni- 

 tration-mixture. The b. p. (163 to 170°) also pointed to the presence of 

 an impurity. 



Recently, Rupe and Kessler 3 ) discovered that in certain conditions the 

 group: N-OH in aliphatic isonitroso ketones was capable of ready sub- 

 stitution by the semicarbazone group. As it seemed interesting to extend 

 this reaction to other compounds of analogous constitution, Rupe and 

 Altenburg 4 ) investigated the action of semicarbazide on cyclic nitroso- 

 chlorides, nitrosites, §c. 



In acting with semicarbazide hydrochloride upon fcislimonene nitroso- 

 chloride, the bimolecular body was first converted into the simple nitroso- 

 chloride, after which hydrochloric acid was split off from the latter, 

 carvoxime being formed. Finally, hydroxylamine was set free, resulting 

 in the formation of carvone. When free semicarbazide, or semicarbazide 

 acetate is used from the initial stage onward, the resultant products are 

 carvone oxime and carvone semicarbazone. 



Iftsterpineol nitrosochloride behaved towards semicarbazide as towards 

 alkalies 5 ); terpineol and the semicarbazone of 8-hydroxy dihydrocarvone 

 (m. p. 176°), being formed 6 ). 



!) Berl. Berichte 43 (1910), 3546, 



2 ) The opt. rot. is not given. 



3 ) Berl. Berichte 43 (1909), 4718. 

 *) Ibidem 43 (1910), 3471. 



5 ) Wallach, Liebigs Annalen 345 (1906), 117; Report October 1906, 122. 



6 ) Comp. Report October 1905, 112; April 1906, 126. 



