— 133 — 

 which with alcoholic potash yielded a propylene oxide R • C H — C H • 



CH 3 . This conversion established the position of the two bromine 

 atoms in the side-chain, and confirmed the accuracy of the pseudo- 

 formula accepted by Hoering for the reactive dibromides. 



The facility with which the bromine atom in the a -position of 

 the dibromides of propenyl phenol ethers is exchanged, was followed 

 up some time ago by Pond 1 ) and Hell 2 ). Hoering 3 ) has again 

 investigated this reactivity in anethol, isosafrol, and the corresponding 

 derivatives brominated in the nucleus, in order to determine whether 

 the entry of bromine in the benzene nucleus influences the mobility 

 of the bromine atom in a-position of the side chain. He thereby 

 found that as a rule these dibromides brominated in the nucleus, 

 if the reaction lasts sufficiently long, lead to the analogous bodies 

 as the dibromides themselves. There were produced in the usual 

 manner substitution and also addition products of the general form 



R • CH(OCH 3 ) • CHBr . CH 3 , 



R.CH(OH).CHBr.CH 3 , 



R • CH(OCOCH 3 ) • CHBr . CH 3 , 



R.C(OCH 3 ):CH.CH 3 , 



R.CH:CBr.CH 3 , 



R-Cj C-CH 3 . 

 In the same measure as the reactivity of the a-bromine atom 

 diminishes with the entry of bromine in the benzene nucleus, the 

 capacity of the ^-bromine atom of splitting off decreases. The /J-bromine 

 atom in the acetates R • CH(OCOCH 3 ) . CHBr • CH 3 , for instance, 

 can only be replaced by acetoxyl with formation of monoacetates 

 R • CH(OH) - CH(OCOCH 3 ) . CH 3 . 



The compounds R.CH(OH). CHBr. CH 3 and R.CH(OCOCH 3 ) 

 • CHBr • CH 3 , which are derived from the dibromides, are, as Hoering 

 published in a preliminary communication 4 ), very readily converted, by 

 boiling with alcoholic potash, in substituted propenyl oxides of the 

 formula R. CH — CH • CH 3 . In a more detailed publication 5 ) 



\>' 



Hoering has continued the study of these oxides, preferably with 

 the oxides derived from mono- and dibromoisosafrol dibromides, as these 

 were suitable for the purpose on account of their crystallisation capacity. 



x ) Journ. Amer. chem. Soc. 25 (1905), 292. Report October 1903, 98. 



2 ) Berl. Berichte 36 (1903), 1184. Report October 1903, 98. 



3 ) Berl. Berichte 38 (1905), 3464. 



4 ) Berl. Beriehte 38 (1905), 2296. Report October 1905, 117. 



5 ) Berl. Berichte 38 (1905), 3477. 



