9 6 SCIENCE PROGRESS 



might by analogy be expected to shift a double bond from the 

 fiy to the a/3 position, 1 were without effect on cholestenone. 

 It seems then that the £7 position is also excluded. Realising 

 that if intramolecular change takes place during these experi- 

 ments the conclusions derived from them are rendered 

 unreliable, Windaus (1906) oxidised the ketone with neutral 

 permanganate which, according to Tiemann and Semmler, 2 is 

 not likely to produce such changes. He found that the chief 

 product of the reaction was a saturated keto-monocarboxylic 

 acid C20H42O3, containing one carbon atom less than the parent 

 substance, and this acid, on further oxidation, passes to a 

 tricarboxylic acid Car.H^Oo, 



/CO /COOH 



COOH - C,^H :j9 < I becoming COOH - C.^H,/ 



\CH 2 \COOH 



" This formation of a keto-acid must negative the explana- 

 tion of cholestenone as an a 13 unsaturated ketone. In that 

 case it appears impossible to construct a scheme whereby an 

 a 13 unsaturated ring system such as 



CH 2 CH 2 



HC C:CH HC CO 



II or || 



HC CO HC CH 



CH, CH 



passes to a saturated keto-monocarboxylic acid with CO bound 

 in the ring and poorer in carbon atoms." As the simplest 

 explanation he suggests that in cholestenone there is an end 

 group CH = CH 2 , which oxidises thus : 



C 2i H 4l O . CH : CH, + 5 . = C s5 H 4l O . COOH + H,0 + C0 2 . 



Combining this with other evidence to be mentioned below, 

 he provisionally writes Cholestenone 



CH, CH, CH., CH* 



C CH CH, . • , ,, • C CH CH, 



■ I ■ which would give . , l 



C CH, CH for the acid C CH, COOH 



CO CH 2 CO 



the double link being in the e£ position to the carbonyl. 



1 Blaise, C. R., 138, 636. * " On Pinene," Ber. 38, 1345. 



