- 156 - 



with application of pyridine, at the temperature of the water-bath, the 

 last-named substance had effected a partial displacement of the double- 

 linking from the a, /? -position to the /?, y- position in the molecule 

 of the citronellidene acetic acid. For this reason the authors advise 

 caution in the determination of the constitution of unsaturated acids, 

 which have been obtained by condensation of aldehydes with acids 

 by means of pyridine. The lactone 



CH 2 v 



^>C • CH 2 • CH 2 . CH 2 • CH • CH • CH 2 . CH, . CO 



CH 3 / I 



CH 3 I O- 



boils at 161 to 163 (13 mm. pressure) and has a peculiar disagreeable 

 odour. — The authors further produced, by the action of methyl- 

 magnesium iodide on citronellal, a secondary alcohol, 2 , 6-dimethyl- 

 nonene-(i)-ol-(8) 



CH 3 OH 



CH, X II 



CH, 



hC • CH 2 • CH 2 • CH 2 • CH • CH, ■ CH . CH 8 



The liquid, with a pleasant odour like roses, boiled at 104 to 105 

 (10 mm. pressure). 



With regard to menthocitronellal from menthone by the chemical 

 action of light, see under Physical Notes, p. 123. 



Ketones. 



Wallach 1 ) and his collaborators have made systematic experiments 

 with reference to the condensation- capability of several terpene ketones 

 with aromatic aldehydes, particulars of which are given in the follow- 

 ing notes. Examined were of ketones: cyclopentanone, 1, 2- and 

 1 , 3 -methyl cyclopentanone (active), cy cloheptanone (suberone), cyclo- 

 hexanone , 1,2- and 1,4- and active and also inactive 1,3- methyl 

 cyclohexanone; of aldehydes: benzaldehyde, o-, m-, p-nitrobenzalde- 

 hyde, o- and p-chlorobenzaldehyde, anisic aldehyde, cuminic aldehyde, 

 piperonal, cinnamic aldehyde, p - dimethylamido benzaldehyde. The 

 conditions of the reaction were as much as possible the same, viz., to an 

 alcoholic solution of the ketone - aldehyde mixture, were added 3 to 

 5 drops of 8 to 10 per cent, caustic soda liquor. If after 12 to 24 hours 

 no condensation had yet taken place, a few more drops were added. 

 In ketones methylated in ortho-position to the CO-group, 1 molecule 

 aldehyde was employed for every molecule ketone; in all other cases, 



x ) Nachr. K. Ges. Wiss. Gottingen 1907, Meeting of 20. July. 



