- 98 - 
two acids. In a special work^) the same investigator gives detailed 
characteristics of ^-methyl adipic acid and of d-pyrotartaric acid an- 
hydride, which he obtained in addition to a series of other acids in 
the oxidation of menthone with permanganate. 
Phenols and phenol ethers. The behaviour of unsaturated 
phenol ethers whose side-chain is saturated with bromine, has been 
examined by Pond and Siegfried 2). As had already been previ- 
ously established by Auw^ers and Miiller^), it was found that the 
brominated propyl -group can only yield glycol ether in the case of 
free phenols. In phenol ethers, on the other hand, of which the 
authors examined in detail monobromisosafrol and -isoapiol dibromide, 
it could be proved, in agreement with previous results, that only the 
bromine atom which stands in the a-position towards the benzene-ring, 
can be readily exchanged for other atom-groups, but not the com- 
paratively stable yff-bromine atom. . - 
Hell and Bauer^) make some communications on aromatic pro- 
pene compounds. They allowed sodium ethylate to act on brominated 
unsaturated phenol ethers, and were able to establish that in the case 
of monobrom-para-anethol dibromide there is first formed a brominated 
propyl ether, which when heated splits off alcohol, and yields a 
y3-brompropenyl compound. With excess of sodium ethylate there 
are obtained from the brominated propyl ether, unstable propenyl 
ethers which are readily converted by acids into ketones. Of a dif- 
ferent behaviour are monobrom - ortho - anethol dibromide (from 
methyl salicylic aldehyde according to Grignard's reaction), and di- 
brominated phenyl propene (from benzaldehyde, after the same 
method). With these bodies the formation of a brominated propyl 
ether could not be observed; moreover, when treated with an excess of 
ethylate, they did not yield propenyl ethers, but the o-anethol deri- 
vative yielded an allylene derivative, whilst in the case of phenyl 
propene dibromide the reaction remained in the first phase (^-brom- 
propenyl benzene). In the para- and ortho -anethol dibromides di- 
substituted in the nucleus, the reactivity of the bromine atoms 
of the side-chain is considerably reduced. The peculiar progress of 
the reaction in these bodies, which reminds of certain transpositions 
of the pseudobromides, induces the authors to accept for their bromides 
^) Journ. russ. phys.-chem. Ges. 35 (1903), 287; Chem. Centralbl. 1903, II. 287. 
^) Journ. Americ. Chem. Soc. 25 (1903), 262. 
^) Berichte 35 (1902), 114. Report April 1902, 95. 
^) Berichte 36 (1903), 206, 1184. 
