— 133 — 



limonene monohalogenhydrate into terpineol (35°) (Semmler) 1 ). The 

 latter can be obtained directly from the aliphatic alcohols geraniol 

 and linalool, and also from the terpene pinene, in the two last-named 

 cases over the intermediate product II 2 ): 



// 

 CH, -C 



CH 9 -CH 

 I 

 CHL.C.CH. 



CH — O 

 CH 3 

 Pinene 



Geraniol is converted by loss of water directly into limonene; 

 L. Tschugaeff 3 ) has also converted carvone into the latter; in carvone 

 therefore the toxicity is solely due to the presence of the carbonyl- 

 group. The more powerful action of the alcohols geraniol and linalool 

 is due to their aliphatic structure; neither the terpineols nor cyclo- 

 geraniol 4 ) (into which geraniol can be converted by ring-closure) show 

 a powerful action. CH,OHCH a CH, 



CH — CH 2 OH 



^CH 2 



/CH = CH 2 



^CH 2 



/CH,. 

 CH,-CH 2 



C CH 3 

 X CH 3 



• COH /CH 2 . 

 CH 2 -CH 2 



c 



CH 3 



Geraniol 





Linalool 





— CH 2 /CH.-CH.OH /CH; 

 ^ -> CH..C.OH /CH,.COH 



1 X CH -CH, X CH, 

 = CH " 2 3 

 Intermediate product (II) 



^CH— CH 2 /CH3 

 CH,-C NcHC-OH 



\ 7 \ 

 X CH 2 -CH 2 CH 3 



Terpineol m. p. 35 



^CH-CH 2 OH ^CH 2 ^C C 



CH 3 .C y CH., -C -> CH 3 -C \CH 



\ X \ \ X " 



XH 2 -CH 2 CH 3 XH 2 CH 2 



Geraniol Cyclogeraniol 



From the aliphatic aldehyde citronellal we arrive by means of 

 acetic acid anhydride at the alcohol isopulegol; by oxidation of the 

 latter with chromic acid in glacial acetic acid, isopulegone C 10 H 16 O 

 was obtained, which is very closely related to menthone. 



OH OH 



yCH.-CH ^CH 2 /CHg-CHOH ^CH 2 /CH,-CO aCH 2 



ch s .ch /CH 9 .c ch 3 -ch \ch-c ch 3 -ch Nch-c 



v/ \ \ x \ \ x \ 



CH 2 -CH, X CH 3 X CH 2 -CH 2 X CH 3 X CH 2 -CH 2 X CH 3 



Citronellal Isopulegol Isopulegone 



x ) Berl. Berichte 28 (1895), 2190. 



2 ) Semmler, Die atherischen Ole, II., 339. Leipzig, 1906, Veit & Co. 



3 ) Accord, to Chem. Zentralbl. 1905, I. 93. 



4 ) H. Hildebrandt, Beitr. z. chem. Pathol. 4 (1904). 



