=e 
idee iG ‘ Notes « ON SCIENTIFIC RESEARCH. = A27F 
ene tre 
we CH Che CHS cH CH, oe CH,——-CH-—-H, 
ee cic) ee (Cri oe | C(CH) 
Stee l ) reat CH. C a CH-Br ae -_CH-Br 
seer Bh: | : oe “cH.cl | bry cH, 
(vin _ (VII) Bi ne eran phan (IX) 2-Bromo-c-methylcamphane. 
_ (camphene dibromide). 
: eh . , | 
Carene.—The turpentine oil obtained in India from the turpentine of Pinus longifolia, 
- Roxb., passes for a poorer product than the American oil. Nevertheless, it is much 
__ used, and the turpentine oil industry In Jallo (Punjab) and in Barely (United Provinces) 
‘is developing satisfactorily. According to earlier works’) the oil contains /-«-pinene, 
saeeriene, a sesquiterpene, and a terpene which ‘on treatment with hydrochloric acid 
_ gives sylvestrene hydrochloride. 
Since there was a supposition that sylvestrene ’ is not criginally present in the oil, 
but that it is the transformation product of an isomeric terpene, J. L. Simonsen?) examined 
on ce more the Indian turpentine oil for its ingredients. In the oil obtained from the 
factory at Jallo (dZo 0.8717; ap — 2.38°; npxo 1.4725; acid value 2.4), he was able to 
confirm the presence of /-«-pinene, @-pinene and a tricyclic Sesaeecinede: In addition, 
g he found a new bicyclic terpene which he named “d-carene” 
For investigation purposes Simonsen separated the oil inte 3 fractions: — up to 118° 
at 200 mm. 31 per cent.; 118 to 130° at 200 mm. 47 per cent.; 149 to 155° at 36 mm. 
~ 19.2 per cent.; loss and residue 11.2 percent. Two distillates were obtained from 
_ these fractions. (1) Between 155 and 167° (60.8 per cent.), containing the pinene. 
(2) Between 167 and 171° (14.8-per cent.), from which after repeated fractionation, 
d-carene (b. p. 123 to 124° at 200 mm.) was obtained. This terpene had the following 
properties: —b. p. 168 to 169° at 705 mm. ; d2> 0.8586; ap se On; Npz30 1.469; 
mol.-refr. 44.23 (reckoned for CioHi¢ /~43.5). op ee was a colourless oil with a 
- characteristic, sweet smell. The solution in acetic anhydride gave a temporary green 
coloration on the addition of one drop of concentrated sulphuric acid. In contrast with 
_sylvestrene and terpinene, carene was not attacked- by chromic acid mixture. It was 
very easily oxidised by the air. No stable nitrosochloride or nitrosite could be obtained, 
but a crystalline nitrosate, however, which decomposed at 141.5°. Also no hydration 
_ tesulted on long treatment with dilute sulphuric acid. Treated with dry hydrochloric 
acid, carene formed d-sylvestrene hydrochloride (I); treated with liquid hydrochloric acid 
re it yielded a mixture of sylvestrene and dipentene hydrochlorides (Il). 
_ From these facts, one of the formula (III), (IV) or (V) could be assigned to carene. On | 
_ oxidation of the terpene in ice-cold NaOH solution with potassium permanganate, a glycol 
~ ¢ 
was formed CioHigO2 (m. p. 69 to 70°), (VI) or (VII). Since this glycol contained no 
- primary-alcohol group, only the formulz (III) and (IV) come into consideration; not 
eed (V). Further, the generation of dimethyl! malonic acid in the acid oxidation of 
, aa 
é. 3 
the terpene, proved that the group (CH; mL is present in the compound. In oxidising 
“with. potassium permanganate according to the method of von Baeyer and Ipatiev*) for 
1) Cf. Report April 1911, 116; October 1911, 93. — 7) Jowrn. ahem. Soc. 117 (1920), 570. — 8) Berl. 
Berichte 29 (1896), 2796. 
