3 8o 



presence of platinum, tetrahydroeudesmene was formed. This had boiling point 

 122-122-5 at 7-5 millimetres ; specific gravity at 20 = 0-8893 ; specific rotation 

 [] D + 10-12, and refractive index at 20 1-48278. 



It was also shown that the reduction of eudesmol by hydrogen in the 

 presence of platinum proceeded differently in an ethereal solution to what it did 

 in the presence of glacial acetic acid ; in the former case the hydrogenation 

 only led to dihydroeudesmol, while in the latter case both the double bond and 

 the hydro xyl group were replaced by hydrogen. 



We have found the hydroxyl group in eudesmoj to be very unreactive, 

 except in the case of acetic anhydride, and have failed to combine it with 

 phthalic anhydride, benzoic acid anhydride, benzoyl-chloride, or phenyl- 

 isocyanate. 



SPECIFIC ROTATIONS OF EUDESMOL. 



The specific rotations of crystallised eudesmol which we have prepared 

 from the oils of the various Eucalyptus species enumerated below, taken in each 

 case in about 12 per cent, chloroform solution, were not always of the same value, 

 as seen from the following results : 



Eucalyptus hcemastoma ... ... ... ... [] D + 38 '43 



E. Moorei ,, . 35'5 



E. Gullicki ... ... ,, 33-65 



E. Rossii ,, 33-58 



E. Macarthuri ... ... ,, 3i'75 



E. ligustrina ... ... ... ... ,, 39-02 



E. phlebophylla ... ... ... ... ,, 27-07 



After two years the comparatively unaltered sample of crystallised 

 eudesmol from E. Macarthuri, mentioned previously, had however lowered 

 slightly in specific rotation to [a] D + 30-46. When distilled at 10 millimetres, 

 the product had again risen to [a] D + 31-68, and thus in agreement with that of 

 the original determination. That two optical isomers are present in ordinary 

 eudesmol is indicated from the above, and also from the results obtained with 

 the sublimed crystals from the liquid eudesmol of E. Macarthuri, as illustrated 

 previously. The specific rotation of the sublimed product was [] D + 37-64, 

 and that of the transparent light amber coloured, brittle residue [] D + 24-93. 

 The mean of these results is [] D + 31-28, almost identical with that for the 

 original eudesmol. 



MELTING POINT OF EUDESMOL. 



The melting point of eudesmol is given by Semmler and Tobias as 78 C., 

 but in all the samples of eudesmol we have prepared from the oils of different 

 species of Eucalyptus, the melting point of the finally crystallised substance has 

 been between 79-80 C. In some species the solid paraffin occurs, together with 

 the eudesmol (E. Moorei for instance), and the melting point may thus easily be 

 lowered. It may be removed by dissolving in alcohol, adding sufficient water 

 to precipitate the paraffin, and filtering it off on a Buchner funnel by the pump. 



When, however, the oil of E. Macarthuri was distilled under 10 millimetres 

 pressure, the product thus obtained melted at 78, and also at the same 

 temperature when sublimed from the water bath, before recrystallising. 



We are not aware from which species of Eucalyptus the eudesmol was 

 obtained upon which Semmler and Tobias carried out their investigations, but 

 from the specific rotations given above and also from the fact that the oil of 

 E. Macarthuri is commercially distilled in Australia, the indications are that it 

 might have been derived from that species. 



