- 1 63 - 



prolonged contact with dilute sulphuric acid; m. p. of the urethane 

 131 to 1 3 2 . 2. Liquid /?-nopinol, a viscid mass from the mother- 

 liquors of the former; [a] D — 15,03° in 13,15 percent, ethereal solution ; 

 m. p. of the urethane 95 to 96°. When heated with zinc chloride 

 it gives a bad yield of a hydrocarbon boiling at 157 to 160°, nopin- 

 onene, whereas a-nopinol is much more stable towards zinc chloride. 

 In addition to the two alcohols, there is formed in the reduction of 

 nopinone, the pinacone C 18 H 30 2 (b. p. 195 to 200° at 1 1 mm. pressure; 

 m. p. 106 to 107°). 



By the action of methyl magnesium iodide on nopinone Wallach 

 obtained homonopinol C 10 H 17 OH (methyl- 1 -nopinol) of the 

 m. p. 204 to 205°. The pure alcohol forms downy needles melting at 

 58 to 59° (from dilute methyl alcohol), has the specific rotatory power 

 Md — 4>99° ( m ethereal solution), and possesses according to the 

 manner of its formation, the following constitution: — 



CH CH 2 



/~~~ \ 



H 3 C.(OH)C(H 3 C-C v — )ch 



CH 2 CH 2 



It may be looked upon as a hydrate of pinene, and by abstracting 

 water there might be formed from it three hydrocarbons, which Wallach 

 designates as a-, /?- and y -pinene: — 



CH CH 2 CH CH 2 C CH 



YX \ /\ 



V 



V \ //_ \ 



H 3 C-C< HX-Cr )CH HX=C( HX-Cr >CH HX.C(H 3 C-Cr )CH 



3 \* X CH 3/ / 2 \ 3 X CH 3 / 3 \ 8 N CH 3/ / 



% / \ . / \ / 



CH CH 2 CH 2 CH 2 CH^ CH 2 



a - Pinene /? - Pinene y - Pinene 



a-Pinene is the ordinary pinene, ^8-pinene the nopinene hitherto not 

 isolated, ^-pinene can no doubt readily be formed from homonopinol, 

 as a tertiarily combined H-atom is present for the abstraction of water. 

 On the other hand, this hydrocarbon will be capable of ready conversion 

 into limonene or terpinolene, with disruption of the tetracyclic ring. The 

 experiment also showed that the tetracyclic ring is split up easily into cis- 

 terpin hydrate, already by shaking homonopinol either with 8 per 

 cent, sulphuric acid, or with cold saturated solution of oxalic acid : — 



CH CH 2 



/\ \ 2^ 



H 3 C .(0H)C(H 3 C-C^— -^CH + H 2 = H 3 C . (HO)C<Q ^CH-C(OH) . (CH 3 



-/ CH, CH 9 



CH 2 CH 2 



