— 171 — 



formed (m. p. 157 ) split up on slow distillation into carbonic acid 

 and anethol. 



Piperonal, when treated in exactly the same manner, yielded, 

 though not quite readily, isosafrol. 



Isosafrol. In continuation of his work on the dibromides of 

 aromatic propenyl compounds 1 ), Hoering 2 ) examined the behaviour 

 of the hitherto not produced tribromo isosafrol dibromide 



CH 2 — O Br 



\Q< >CHBr.CHBr- CH,. 



Br Br 



Whereas in the case of anethol it had not been possible, even 

 by energetic bromination, to introduce more than two bromine atoms 

 into the nucleus, it was found that under certain conditions in iso- 

 safrol all three hydrogen atoms in the nucleus could be replaced by 

 bromine, if isosafrol was allowed to drop into a large excess of bromine, 

 and the reaction -temperature was maintained at about 30 to 35 . 

 Under such conditions only the tribrominated dibromide, briefly called 

 "isosafrol pentabromide", of the m. p. 196,5 to 197 , was formed; 

 but if the brominating took place at 60 to 63 °, so that vapours of 

 bromine and hydrogen bromide escaped, there was almost exclusively 

 formed the well-known dibrominated isosafrol dibromide of the m. p. 

 129 to 130 . The reaction- capacity of the pentabromide, which finds 

 expression particularly in the readiness with which the dibrominated side- 

 chain is attacked, has become much reduced in comparison with that of 

 the lower-brominated derivatives; thus, the body no longer reacted with 

 aqueous acetone, with alcohol, concentrated hydrobromic acid, and 

 alcoholic potash; also when treated with fusing potash or with chromic 

 acid and glacial acetic acid, the bulk of the pentabromide remains 

 unchanged. On oxidation with permanganate, there was formed, by 

 secondary alkali action, a small quantity of tribrominated isosafrol 

 oxide. On the other hand, the two bromine atoms in the side- 

 position could be removed by reduction by means of zinc dust in 

 benzene - alcoholic solution, with formation of the tribromo isosafrol 

 C 6 Br 3 (0 2 CH 2 )CH:CH.CH 3 of the m. p. no to ni°, which is very 

 stable towards permanganate. The same reaction could also be 

 carried out with di- and monobromo isosafrol dibromide. When treated 

 with bromine, tribromo isosafrol yielded back pentabromide; in sunlight, 

 the original pentabromide was formed; but a new not yet further 



J ) Berl. Berichte 37 (1904), 1542; 38 (1905), 2296, 3458, 3464, 3477. Report 

 October 1904, 11 ; October 1905, 117; April 1906, 132.- 

 2 ) Ibidem 40 (1907), 1096. 



