— 131 — 



Further oxidation of the glycerol with bichromate and sulphuric acid 

 yields succinic acid, m. p. 183 to 185°, together with a lactone, m. p. 210 

 to 220°, which, when treated with nitric acid, is likewise converted into 

 succinic acid; but neither la^vulic acid nor methylheptenone is formed. 

 When the glycerol is carefully oxidised with a quantity of bichromate 

 calculated for 1 atom oxygen, it is also possible to isolate the dihydroxy 

 aldehyde, which very readily reduces ammoniacal silver solution. 



All the data enumerated above indicate that the alcohol which is 

 formed by hydrating dihydromyrcene must possess the constitution of 

 dihydrolinalool (2,6-dimethyloctene-l-ol-6). 

 CH 2 x 



\C • CH 2 • CH 2 • CH 2 • COH • CH 2 • CH 3 . 



CHs CH S 



For purposes of comparison we have prepared the alcohol according 

 to Enklaar's method 1 ), by reacting with magnesium iodoethyl upon methyl- 

 heptenone (obtained by oxidising citral): — 



B. p. 77 to 78° (7 mm.) or 83 to 84° (9 mm.); d 13 o 0,8588; n D15 o 1,45641 ; 

 n D20 o 1,45471 ; « D 4-0; mol. refr. found 49,46, calc. as Ci H 20 O/T 49,438. 



Enklaar gives the following constants: di 5 o 0,8695, n D150 1,4569. It may 

 be questioned, however, whether these values are correct, for by all ex- 

 perience it appears to be impossible that the disappearance of an ethylene- 

 bond should not be attended by a concurrent decrease of sp. gr. (e. g., 

 geraniol-citronellol, carvone-dihydrocarvone-tetrahydrocarvone, 8jc). 



The phenylurethane of dihydrolinalool prepared from methylheptenone 

 does not form so readily as that of dihydrolinalool prepared by the hydra- 

 tion-method. It was most difficult to obtain it in the pure state and it 

 appears to consist of a mixture of the two isomerides (the limonene- and 

 the terpinolene-modification). 



The alcohol prepared from methylheptenone (from lemongrass oil) 

 and from magnesium ethyl iodide also yielded no uniform phenylurethane. 

 The constants of this alcohol resembled those of the alcohol obtained 

 from the synthetic methylheptenone, b. p. 66 to 66,5° (4 mm.), di 50 0,8575, 

 « D ±0, n D20O 1,45391, mol. refr. found 49,558, calc. for Ci H 20 O/T 49,438. 



Ci/cZodihydromyrcene, the body which, together with the alcohol, was 

 formed in the process of hydration, boiled between 167 and 169°; di 50 0,8328; 

 n D150 1,46288; mol. refr. found 45,63, calc. as Ci Hi 8 /r 45,61. 



Ctyc/odihydromyrcene Cfydodihydromyrcene CtycZolinaloolene 



(Schimmel 8j Co.) (Semmler) 



B. p. 167 to 169° 169 to 172° 165 to 167° 



Sp.gr. 0,8328(15°) 0,828) 



Refraction 1,46288(15°) 1,4621 (2 



Mol. refr. 45,63 45,63 



x ) Recueil trav. chim. des P.-B. 27 (1908), 411. Comp. Report April 1909, 125. 



9* 



