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semicarbazone meltiner at 197°, whilst citralsemicarbazone melts 

 at 135°. Here we have a difïerence in the method of research. 

 Power and Kleber tested for citral by converting it into citrjl- 

 naphtocinchonic acid ; in tliis way a possibly formed ketone — I 

 presume myrcenol is a secondary alcohol — must have escaped their 

 notice, whilst a little citral thus detected may be simply a by-product. 

 On the other hand, semicarbazone, made use of by Barbier, is 

 according to others unfit for testing for citral. Barbier may have 

 obtained the semicarbazone from the eventually formed ketone, the 

 main product, whilst a little admixed citral may have given the 

 aldehyde reactions. Moreover Barbier's oxidations with permanganate 

 in aqueous solutions cannot be taken as decisive for the differen- 

 tiation of myrcenol and linaloöl '). 



Instead of investigating the oxidation products of myrcenol, I have 

 prepared from the alcohol itself a crystallised derivative, in the form 

 of a phenyl-urethane, melting at 68°. The analysis again pointed to 

 the composition Cu H„ OjN. This urethane has been prepared in the 

 same manner as Walbaum and Hüthig ") prepared the phenyl-urethane 

 from linaloöl; the latter melts at 65°. By means of the phenyl-urethane 

 obtained from myrcenol, it could be decided very readily and distinctly, 

 that the alcohols, myrcenol and linaloöl, were totally different. The 

 mixture of racemic linaloolurethane and myrcenol-urethane melted 

 at 60'' — 62° ; the depression of the melting point sufficiently proves 

 the non-identity. The alcohol, which is characterised by the phenyl- 

 urethane melting at 68^, is also the main product of crude myrcenol. 

 I obtained from this a yield of nearly 60 pCt. of crystallised urethane ; 

 besides this alcohol, a little linaloöl may possibly be contained in 

 the myrcenol (the hydration product of myrcene) ; the formation of 

 some ' oily urethane in presence of the crystallised substance might 

 even point to this. The facts mentioned render it possible, however, . 

 to decide the matter. By regenerating mj'rcenol from its urethane, 

 the properties of pure myrcenol may be ascertained. I am still engaged 

 with this. Of this alcohol, myrcenol, it may be stated that it is a 

 typical derivative of myrcene; its constants differ from those of 

 ocimenol, in the same manner as those of myrcene do from those 

 of ocimene; the tendency towards polymerisation of myrcenol is 

 still larger than that of mVrcene. 



For ocimenol and myrcenol I devised provisional structural formulae'), 

 based on their formation from the terpenes ocimene and myrcene. 



M Compare previous communication. 



») Journ. f. prakt. Ghem. 67, 323 (1903). 



') Dissertation, p. 73. 



