— 97 — 



when the bulk of the shipments from the Hokkaido usually appears upon 

 the market, the movement in prices were to undergo a change. However 

 this may be, surprises are always possible, and it is necessary to use 

 great circumspection when estimating the future of these two important 

 articles, which have been so often the subject of speculative enterprise 

 in the past. At present the quotation for crude menthol is 9/8 d. per lb., 

 and for peppermint oil 6/- per lb. 



We have been able to prove the presence in Japanese peppermint 

 oil of a new constituent, ^-menthenone, a ketone which, so far, had not 

 been found in essential oils. In order to isolate it from the oil we made 

 use of its property of forming an additive compound with sodium sulphite. 

 The ketone is identical with that already prepared by Wallach 1 ) from 

 1 , 3, 4-trihydroxyterpane by elimination of water, but it differs from the 

 ^-menthenone obtained by Callenbach 2 ) by acting with methylene iodide 

 upon sodium acetoacetic ester and introducing the isopropyl group. It 

 is true that Rabe and Rahm 3 ), and also Merling 4 ), had already shown that 

 the sequence of reactions followed by Callenbach could not yield a ketone of 

 the constitution of zF-menthenone, but the definite proof that Callenbach's 

 ketone has nothing to do with z^-menthenone can only be said to have been 

 given by Wallach's synthesis and by the present more detailed investigation. 



As already stated, we isolated the ketone by means of the sulphite com- 

 pound, from the solution of which we removed those products which had 

 not combined with the sodium sulphite by repeated extraction with ether, 

 after which the ketone was liberated with potash liquor. The crude ketone 

 obtained by this method possessed the following properties: b. p. 101 to 

 103° (7,5 mm.), d 15 o 0,9387, « D + 0° 30', n D20 o 1,48675. When purified by re- 

 peated fractionation the ketone boiled between 235 and 237° (752 mm.); 

 d 15 o 0,9382, d 20O 0,9343, « D + 1°30', n D20O 1,48441, mol. refr. found 46,58, calc. 

 for CioHi 6 l 45,82. But if the calculation of the molecular refraction is 

 based upon the fact that /F-menthenone belongs to the compounds with 

 a conjugated position of the double bonds, and that it closely resembles 

 the «,^-pulenone prepared by Auwers and Hessenland 5 ), which shows an 

 exaltation of 0,83, then the molecular refraction comes out at about 46,62. 



I. 0,1354 g. subst: 0,3913 g. C0 2 , 0,1302 g. H 2 0. 

 II. 0,1366 g. subst: 0,3950 g. C0 2 , 0,1344 g. H 2 0. 



Found Calc. for Ci Hi 6 O 



I. II. 



C 78,82 °/o 78,86 °/o 78,94 °/o 



H 10,68°/o 10,93°/o 10,52°/o. 



a ) Liebigs Annalen 362 (1908), 272; Report November 1908, 181. 



2 ) Berl. Berichte 30 (1897), 639. 



; ) Ibidem 38 (1905), 969. 



*) Ibidem 980. 



') Berl. Berichte 41 (1908), 1812. 



