— 171 — 



Limonene. According to G. Cusmano 1 ) the reaction of hydroxylamine 

 upon d-limonene «- and /?-bisnitrosochloride leads to two isomeric cis-trans- 

 hydroxyl amino oximes, which are to be differentiated as «- and /?-modi- 

 fications. The a-modification from the «-nitroso chloride of d-limonene 

 consists of colourless crystals, which begin to fuse at about 145° and to 

 decompose at about 150°; [«] D +17,73°, m. p. of the hydrochloride 142°. The 

 «-hydroxylamine of the d-limonene-/?- bisnitrosochloride is converted in 

 the presence of small quantities of salts into an isomeride, which forms 

 golden-yellow prisms, m. p. 167,5°. 



On the reduction of limonene, see p. 166. 



On the action of semicarbazide and of magnesium upon limonene 

 nitrosochloride, see p. 166. 



Terpinene. An interesting synthesis of a hydrocarbon which is probably 

 isomeric with terpinene has been carried out by G. G. Henderson and 

 M. M. J. Sutherland 2 ). These authors hydrogenated thymohydroquinone 

 (hydroxythymol) by Sabatier-Senderens' method at a temperature of from 

 190 to 200°. The product of reaction, menthane-2,5-diol, crystallised out 

 from benzene in small, colourless, odourless flakes, m. p. 112°; b. p. about 

 155° (15 mm.). It dissolved readily in the usual organic solvents. In 

 addition there was probably formed the ketone, menthane-2,5-dione, 

 corresponding to menthane-2,5-diol. The semicarbazone of this ketone 

 melted at 243 to 244°. When menthane-2,5-diol was heated 190 to 200° 

 for half an hour with twice its own weight of sulphate of potash in a 

 reflux-condenser, it yielded a terpene hydrocarbon possessing the following 

 constants: b. p. 179° (760 mm.), d about 0,84, n D20 o 1,4779. No characteristic 

 derivative was obtained, the available quantity of the hydrocarbon being 

 insufficient for a closer investigation, but it is expected that such an in- 

 vestigation will shortly be undertaken. 



On the reduction of «- and /?-thujene, see p. 169. 



Caryophyllene. On p. 180 of our last Report we recorded the results 

 of a brief examination of caryophyllene. We then pointed out that there were 

 no longer any great difficulties in the way of preparing caryophyllene dihydro- 

 chloride from oil of clove-stems provided our directions were followed, and that 

 this compound is very serviceable for identifying and detecting caryophyllene. 

 While splitting off hydrochloric acid by means of dilute alkali solution or 

 sodium ethylate, we had obtained from the dihydrochloride a hydrocarbon 

 which, from its molecular refraction, we felt justified in believing to be 

 a tricyclic sesquiterpene. Semmler and Mayer 3 ) have continued these 



*) Gazz. chjm. ital. 40 (1910), I. 602. Quoted from Chem.- Zentralbl. 1910, II. 1221. 



2 ) Journ. chem. Soc. 97 (1910), 1616. 



3 ) Berl. Berichte 43 (1910), 3451. 



