140 



A. R. PENFOLD. 



interesting ketone. Although the work is not yet com- 

 pleted, in view of the great interest evinced in this body 

 since the publication of the paper (I.e.), more particularly 

 in the technical press, the writer felt justified in making 

 available, as soon as possible, any conclusive evidence 

 determining the position of the double linkage, A further 

 reason for this decision, was that whilst preparing this 

 note, the "Perfumery and Essential Oil Record" of March 

 1921, page 80, came under notice, wherein appears an 

 article on the constitution of piperitone by Messrs. L. 

 Givaudan & Co., Vernier, Geneva, Switzerland. This firm 

 make certain deductions based on theoretical considerations 

 and upon a comparison of the chemical and physical con- 

 stants given by Messrs. Wallach, Schimmel & Co., and 

 Roberts, for various preparations of A'-Menthenone-3, and 

 mention that very likely piperitone is identical therewith. 



From the oxidation products of piperitone the author 



isolated diosphenol, a ketophenol, whose structure is well 



known. It was synthesised by Messrs. Semmler and 



McKenzie in 1906, and by Ousmano in 1913, so that the 



position of the double bond in this body has been established 



beyond doubt. It is as follows, viz.: — 



OHs 



I 

 C 



H 2 

 HoC 



I OOI1 

 J CO 



/ 



CH 

 CH 



H a O 



CH 



As the double bond in this ketophenol is in the first 

 position, it naturally follows that it is conclusive evidence 



