142 



CH 2 CH CH-CH„ CH, CH CH-CH,, 



I III 



CH 3 — C — CH 8 -> CH 3 — C — CH 3 



I I 

 CH 2 CH CO CH 2 CH C< 



Fenchone ^ Homofenchyl alcohol 



OH 

 CH Q 



CH, 



CH 



C-CtL CH, 



-CH 



CH-CH, CH, 



-CH- 



CH- CH, 



CH Q — C — CH D 



C H Q — C — C Ho 



CH Q — C — CH, 



CH, 



-CH- 

 I. 



■CCE 



CH, 



-CH- 

 II. 



C:CH, 



CH, 



CCH, 



III. 



Homofenchene 



Terpinene. In our last Report (p. 137) we had occasion to 

 mention the conversion of sabinene into terpinene compounds. In 

 the meantime, our knowledge of the relation between the sabinene 

 and the terpinene series has been enriched by a work of Wallach 1 ). 

 In the same manner as nopinone (see p. 165) he also employed the 



sabina ketone C 9 H 14 O 



-C Q H 7 



for syntheses which, as might be expected, led to terpinene derivatives, 

 By the action of methyl magnesium iodide on sabina ketone, 

 Wallach obtained methyl sabinaketol, or sabinene hydrate 

 C 10 H 18 O, which boils at 195 to 201 with slight loss of water, and 

 melts at 38 to 39 . It has a terpineol-like odour, and is completely 

 stable towards potassium permanganate. With glacial acetic acid and 

 hydrogen bromide it yields, with dissolution of the tricyclic ring, terpinene 

 hydrobromide; when shaken with 5 per cent, sulphuric acid, terpinene 

 terpin (m. p. 13 7 ) is formed. By the action of ethyl magnesium 

 iodide, ethyl sabinaketol C^E^O was obtained from sabina ketone. 

 The decomposition of the magnesium double compound was not in 

 this case effected with an acid, but took place in a current of steam, 

 as the alcohol, like the methyl compound, is sensitive towards acid. 

 When shaken with dilute sulphuric acid it yielded the homologous 

 terpinene terpin (m. p. 141 to 142 ), which, when slowly heated, 

 sublimes in white leaflets, and in contact with glacial acetic and hydro- 

 halogen acids yields the corresponding halogen derivatives: dihydro- 

 chloride of the m. p. 67 to 68°, dihydrobromide of the m. p. 88 

 to 89 , dihydriodide of the m. p. 89 to 90 . 



*) Nachr. K. Ges. Wiss. Gottingen 1907, Meeting of 20. July. 



