149 ~ 



(12 mm. pressure) from pinene hydrochloride magnesium and the sul- 

 phurated reaction-products non- volatile with water vapour, was ident- 

 ified by conversion in camphoroxime (m. p. 117 to 11 9 ). 



Oxides. 



C i n e o 1 . We have already on several occasions reported x ) on 

 Rupe's work regarding the behaviour of cineolic acid from a chemical 

 as well as from a physical point of view. Further experiments carried 

 out by R u p e conjointly with W. Lotz 2 ), deal with the effect of 

 bromine on cineolic acid anhydride. Cineolic acid itself is not attacked 

 by bromine; on the other hand, the latter acts on the anhydride of 

 the acid with a violence similar to an explosion. The authors ob- 

 tained one liquid and also two solid crystallising bromine derivatives. The 

 two solid bodies which can be separated by fractional crystallisation from 

 methyl alcohol, are isomeric, and have the rough formula C 9 H u 3 Br 3 . 



The bromide A crystallises from methyl alcohol in white needles 

 or brilliant crystals, but also as a granular crystal powder; the melting 

 point lies at 156 to 157 . The bromide B melts after recrystallisation 

 from alcohol at 129 , and crystallises from methyl alcohol in large 

 tablets. Both bromides show the character of lactones; halogen is 

 best split off by treatment with zinc dust and alcohol. The body 

 resulting from this has the properties of a ^-lactone, which on slow 

 distillation at 170 (ordinary pressure), is converted, with loss of carb- 

 onic acid, in methyl heptenone (IV) (b. p. 1 73°); the latter was 

 identified by its semicarbazone (m. p. 134 ). 



The course of the reaction, i. e. the splitting off of CO from 

 cineolic acid anhydride, is conceivable in two directions, whereby 

 the substitution of the H -atoms by bromine need not for the present 

 be taken into account. The following formulae explain the reaction: — 



CH 

 H 2 C 



'X 



CO 







H,C 



\/ 



C /CH 3 

 X CH 3 

 CO 



O — CO 



CH 3 

 ^CH 3 



CH 3 

 CH, V 



I O 1 



)C-CH.CH 2 .CH 2 .C.CH 3 (II)- 



CO- 



O 



r 



O 



>C.CH.CH 2 .CH 2 .C.CH 3 (III). 

 O CO 



CO -f >C:CH.CH,.CH 2 .CO.CH 3 <- 



CH3/ 



(IV) 



J ) Reports October 1900, 76; April 1901, 70; October 1905, 109. 

 -) Berl. Berichte 39 (1906), 4076. 



