— 172 — 



The author has succeeded in converting the inactive hydroxylamine oxime 

 (decomposition-point 140°), into two salts of the acid in question (decom-* 

 position-points 195 and 172° respectively). When the salts were resolved 

 with soda they gave rise respectively to a dextrorotatory and a lasvo- 

 rotatory oxime, decomp. pts. 147 and 145°, [a] D in methylalcoholic so- 

 lution + 60,74 and —59,66°. 



Isop in en e. N. Zelinsky 1 ) describes isopinene, a hydrocarbon which is an 

 isomeride of a-pinene. With the object of preparing this body, 1-a-pinene 

 (b. p. 155 to 155,5°; d^ 0,8587; [«] D — 43,81°; n D20O 1,4652) in absolute 

 ethereal solution was allowed to react with palladium black. After a few 

 hours, hydrogen was passed into the liquid at ordinary temperature, giving 

 rise to isop'mene possessing the following constants: b. p. 158,5 to 159,5°, 

 d^0,8573, [«] D — 38,09°, n D20O 1,4641. Neither hydrochloride nor nitroso- 

 chloride is formed. Zelinsky assumes that a-pinene first absorbs hydrogen, 

 under formation of hydropinene, and that *sopinene results from the latter,, 

 somewhat after the following reaction: — 





y 



C-CH 



Is 





( 



CH*CHs 





CCH 3 



HC 



y 



CH 



H 2 c/ ^ 



CH 



H 2 c/ 



^c 





(CHs)2C / 







(CH 3 ) 2 (X 







(CH 3 ) 2 C^ 





H 2 C 





y 



CH 2 



H 2 C 







CH 2 



H 2 C 







)cH* 



C 



:h +p d + 



H 2 --> C 



;h 



-fPd- 



C 



:h 



+ H 2 + Pd 





«-Pi 



nene. 







Hydrc 



pinene 







Isopi 



nene 





The behaviour of a-pinene towards palladium black is very different 

 when it is exposed for a period of 4 weeks to the action of hydrogen 

 under very low pressure. In this case it yields hydropinene (b. p. 167,5 

 to 168°; d^ 0,8567; [«] D — 19,84°; n D20O 1 ,4605). When reducing a-pinene 

 by Sabatier's method, the author obtained a mixture of two hydrocarbons 

 (b. p. 163,5 to 165° and 168 to 168,5°). 



Isopinene, the hydrocarbon which was described by Aschan 2 ) a few 

 years ago, is not identical with Zelinsky's tsopinene, as is evident from a 

 comparison of the constants, as well as from the structural formulas given 

 by the respective authors. Apparently Zelinsky has overlooked Aschafcs 

 publication, otherwise he would certainly have named his hydrocarbon 

 differently. 



*) Berl. Berichte 44 (1911), 2782. 



2 ) Berl. Berichte 40 (1907), 2250; Ofversigt af Finska Vetenskaps-Societetes Forhand- 

 lingar 51, 1. Afd. A, Nr. 9. Corap. Report October 1907, 136; October 1909, 169. 



