— 120 — 



with an odour of camphor and cineol. Its semicarbazone, after being 

 recrystallised from alcohol, melted at 224°, this m. p. not being depressed 

 when the semicarbazone was mixed with that from the sandalwood-ketone. 

 A mixture of the two ketones also showed the right melting-point. Accord- 

 ing to Semmler the formula of the ketone is in all probability as follows : — 



CH 3 



H 2 C 



H 2 C 



This formula indicates the resemblance to camphor, inasmuch as the 

 ketone differs from the latter only in having one methyl-group less. Up 

 to the present this body has not been found in other essential oils; in fact, 

 cyclical ketones with fewer than 10 carbon atoms have never yet been 

 isolated from essential oils. We intend to use the name "santenone", 

 which was also used by Aschan, for the ketone, as that term expresses 

 its relationship to santene, teresantalic acid, and santalol and, consequently, 

 also to sandalwood oil. 



Santenone alcohol. The fractions freed from santenone still con- 

 tained, according to the result of their acetylation, small quantities of alco- 

 holic constituents. By boiling with concentrated formic acid and heating 

 the saponified alcohol with phthalic acid anhydride to 140°, we obtained 

 a liquid acid of phthalic ester of which the sparingly soluble silver-salt 

 did not melt even at 230°. The solid alcohol which was isolated by 

 saponifying the acid of phthalic ester had an odour of borneol and camphor 

 and melted at 196 to 198°; the crystals removed from the semi-solid mass 

 melted at 58 to 62°. Oxidation with chromic acid gave santenone, of 

 which the semicarbazone had a melting point of 223 to 225°. With 

 santenone semicarbazone derived from another source the m. p. of this 

 santenone was not depressed. With phenylic isocyanate the alcohol formed 

 a liquid phenylurethane. 



Oxidation revealed the close relationship of the alcohol to santenone. 

 It is, however, not identical with santenol (^-norborneol) which is obtained 

 from santene by hydration, but is only stereo-isomeric. On the other 

 hand, it agrees in its properties, as well as in its entire behaviour, with 

 7r-nor-isoborneol , which was obtained by Semmler by the reduction of 

 ^-norcamphor (santenone), and which was also prepared by us, for pur- 

 poses of comparison by the same method. The two alcohols form a liquid 

 phenylurethane and cannot be converted into the ethers by heating with 

 alcohol and sulphuric acid. But the behaviour of santenol from santene 

 is similar to that of isoborneol (the product of the corresponding reaction 

 of camphor), inasmuch as it is readily converted into the ether. 



