374 



The crude oil was first distilled and the portion which came over below 

 isy C. removed. The remainder was repeatedly distilled under reduced pressure 

 until finally a fraction boiling at 100-103 C, at 10 millimetres was obtained. 

 This had specific gravity at 15 C. = 0-9326; rotation a D -28-7°; refractive 

 index at 20 = 1-4780. 



As this fraction contained piperitone, it was removed by agitating with a 

 solution of normal sodium sulphite ; the ketone thus recovered in a pure condition, 

 represented 17 per cent, of the fraction. It had all the characters of piperitone 

 and on reduction with sodium amalgam in alcoholic solution gave the solid 

 dimolecular ketone melting at 149-150° C. 



The unabsorbed portion was again refractionated, when an oil boiling at 

 95-96° C. at 10 millimetres was obtained. This had :— 



Specific gravity at 22° C = 0-9230. 



Rotation a D ... ... ... ... ... ... - - 34-1° 



Refractive index at 22° C. = 1-4760. 



The molecular refraction calculated for a C IO H l8 alcohol with one double 

 bond is 47-14 ; found 47-04. 



It is thus apparent that the lasvo-rotation of the alcohol was — after dis- 

 tillation — greater than that of the corresponding ketone, but this may be partly 

 due to the lowering of the optical rotation of piperitone under repeated distillation. 



A portion of the alcohol was oxidised in the cold by the potassium 

 bichromate method ; when the reaction was complete the product was steam- 

 distilled, the oil separated and agitated with a solution of neutral sodium sulphite 

 in the cold, until practicallv the whole was absorbed. The regenerated product 

 had all the characters of piperitone, and gave the solid dimolecular ketone on 

 reduction with sodium amalgam. The piperitone thus formed had specific gravity 

 at 15° C. = 0-9390; rotation a D -- 24-0°; and refractive index at 20° = 1-4832. 



Eudcsmol, the Bicyclic Sesquiterpene Alcohol of 



Eucalyptus Oils. 



Crystallised eudesmol was first discovered by us in the oil of Eucalyptus 

 piperita, and announced in a paper read before the Royal Society of New South 

 Wales in August, 1897. Later, further work upon this substance was submitted 

 to the same society, by one of us, in a paper read August, 1899. The name 

 eudesmol was derived from Eudesmia, which had been applied to the genus by 

 Robert Brown. 



When first isolated, eudesmol was thought to be an oxide related 

 somewhat in constitution to cineol, but from the work carried out later by 

 Semmler and E. Tobias (Ber. 46, 1913, 2026); and Semmler and F. Risse (Ber. 

 46, 1913, 2303); it was shown to be a bicyclic sesquiterpene alcohol, and to 

 contain two rings and one double bond. The reaction with bromine in 

 chloroform solution also shows it to be unsaturated. 



During the last twenty years we have obtained much information 

 concerning eudesmol and its peculiarities, and have isolated this interesting 

 substance from the oils of numerous species of Eucalyptus. 



There appears to be little doubt but that eudesmol occurs in Eucalyptus 

 oils in both the liquid and crystallised conditions, although the line of demarcation 

 separating these is evidently slight. It also appears that liquid eudesmol is 

 the more stable form, because in nearly every case the tendency has been for the 



