Notes on scientific research. 



145 



The hydrolysis of the product of the reaction gave an alcohol (II) which, when 

 distilled under atmospheric pressure, split off water, forming thereby rac. a-fenchene, 

 boiling between 154 and 156°; d 2 ^ 0.8660; n D20 o 1.47045. They first took it for iso- 

 pinene 1 ) owing to its identical qualities. However, the action of ozone on a-fenchene 

 gave absolute proof of its constitution, as hereby rac. a-fenchocamphorone semi- 

 carbazone, m. p. 220°), as well as a monobasic acid Ci Hi 6 O 2 , melting at 105°, 

 rac. a-fenchenylanic acid, were the resulting products. By way of comparison the 

 authors prepared isopinene from c^/dofenchene hydrochloride; its oxidation with potassium 

 permanganate produced rac. hydroxy-a-fenchenic acid (m. p. 139 to 140°) gave no 

 depression of the melting point with the hydroxy-acid prepared from rac. a-fenchene, 

 accordingly no fenchenonic acid had been formed. . The action of ozone produced the 



H 2 C 



H 2 C 



CH 



H 3 CCCH a 



CH 2 



CO 



H 2 C 



. CH 



(I) a-Fenchocamphorone. 



CH 



HsC-CCH 



CH 



CH 2 



< 



CH 3 

 OH 



H 2 C 



H 2 C 



CH 



H 3 C-C-CH 3 



CH 2 



C:CH 2 



(II) Alcohol, reaction product of 



fenchocamphorone and methyl- 



magnesiumiodide. 



CH 



(III) a-Fenchene. 



same compounds. Besides this, the hydrochlorides of isopinene and of the synthetical 

 rac. a-fenchenes are identical. The fenchenonic acid obtained by Aschan 2 ) from iso- 

 pinene would have been according to Komppa and Roschier rac. d,Z-hydroxy-«-fenchenic 

 acid polluted with apocamphoric acid. That this mixture splits off bromoform under 

 the influence of sodium hypobromite, as Aschan observed, was probably based on an 

 error, because fenchocamphorone, in connection with the smell of the hypobromite, 

 produces a smell resembling bromoform. 



Rac. a-fenchene, obtained according to Wallach's method, when treated with ozone, 

 gives rac. a-fenchocamphorone and rac. a-fenchenylanic acid. 



The hydrochloride of the rac. a-fenchene can easily be obtained by the action of 

 hydrochloric acid on rac. a-fenchene, prepared according to Wallach's method. M. p. 35 

 to 37°; b. p. 81° (12 mm.). No depression of the melting point takes place when it 

 is in contact with the hydrochloride of isopinene. 



To judge from the fact mentioned above, the term "isopinene" for the hydrocarbon 

 obtained from pinene hydrochloride ought to be abolished. It is not apparent, however, 

 from the abstract if Komppa and Roschier have expressed themselves in this sense. 

 At the time that Zelinsky called the hydrocarbon prepared from pinene by means of 

 reducing substances "isopinene", he had no right to do so, as this term had already 

 been applied to another compound. Accordingly, the strange case would present 

 itself that a term which had been disposed of without any right should justify its 

 existence owing to subsequent investigations. 



x ) I.sopinene is a hydrocarbon which, according to Aschan, is produced from pinolcne hydrochloride by 

 splitting off the acid. Aschan obtained pinolene from the mixture of liquid chlorides resulting from the pre- 

 paration of pinene hydrochloride by decomposition with alkali (Berl. Berichte 40 [1907], 2250; Report October 

 1907, 137; vide also Report October 1909, 169). A quite different substance is the wopinene described later 

 on by N. Zelinsky which is prepared by treating pinene with palladium black and hydrogene {Berl. Berichte 

 44 (1911), 2782; Report April 1912, 172. Vide also liber die Totalsynthese des Isopineth*, Finnische Akademie 

 der Wiisenschaften, Protokoll der Plenarsitzung vom 4. Oktober 1916). — ") Ofeersigt af Finska Vete?u*kaps 

 Societetens Fdrhundling 51, I. Afd. A, Nr. 9; Report October 1909. 169. 



10 



