— 143 — 



With the help of sabina ketone, Wallach was also able to carry 

 out the synthesis of a terpinene (/?- terpinene). The ketone was 

 condensed in the usual manner with bromoacetic ester and zinc, into 

 the hydroxy ester; from the latter, water was split off, the unsaturated 

 ester formed was saponified, and the acid (m. p. 47 to 4 8°) slowly 

 distilled at ordinary pressure. The hydrocarbon C 10 H 16 (b. p. 176 ; 

 d 0,843; n r> i j4773) mol.refr. found 4 5,61, calculated for C 10 H 16 /^4 5, 2 4) 

 thus formed, with loss of carbonic acid, has two ethylene linkings, 

 and behaves like terpinene. With glacial acetic acid and hydrogen 

 chloride it yielded terpinene dihydrochloride (m. p. 52 ), and with 

 nitrous acid terpinene nitrosite, which could be identified by the nitrol- 

 piperidide (m.p. 154 ). To this terpinene, which he calls /^-terpinene 

 Wallach gives the following constitution: — 



CH 2 C H 2 



H 2 C:C/ )CC 3 H 7 



CH 2 CH 



assuming that the intracyclic bond of sabina ketone is converted in 

 the course of the reactions described into an ethylene bond, whilst 

 the loss of water from the hydroxy ester, like in all analogous cases, takes 

 place in the direction towards the side chain, so that in splitting off 

 carbonic acid, a methene-group is formed. The formation of the 

 ordinary terpinene nitrosite from the hydrocarbon would then be 

 accompanied by a re-arrangement, — an assumption which requires 

 further experimental support. 



Sabinene. As mentioned by us in our last Report 1 ), Semmler 

 obtained by treatment of sabinene with hydrochloric acid gas, a mixture 

 of a mono- and a dihydrochloride. Wallach 2 ) then showed that the 

 monochloride alone is obtained, if every trace of moisture in the 

 process referred to is excluded. Semmler 3 ) has now also produced 

 in this manner the monochloride, and has communicated the results 

 of a detailed examination of the latter. By reducing the chloride 

 (b.p. 82 to 86° at 9 mm. pressure; d2o° o>97o; n D 1482; a D — o° 15') 

 with sodium and absolute alcohol, there was obtained the hydrocarbon 

 dihydroterpinene C 10 H 18 (b.p. 57 to 6 o° at 9 mm. pressure; d2o° 0,8184; 

 a D -j- 12 30'; "d 1,4566; mol. refr. found 45,4, calculated for 

 C 10 H 18 /~ 45,64), which yielded a nitrosochloride (m. p. 87 ) and a 

 benzylnitrolamine (m. p. 107 ). On oxidation with ozone, the keto 

 aldehyde C 10 H 18 O 2 (b.p. 119 to I2 5°at 9 mm. pressure; d 2 o° 0,9439; 



') Report April 1907, 140. 



2 ) Ibidem, 141. 



3 ) Berl. Berichte 40 (1907), 2959. 



