BROMINE WATER IN SYNTHETIC ORGANIC CHEMISTRY. 563 



acid dibromide, the complete series of reactions involved 

 may be summarised as follows: — 



Br 2 + HOH ^ZZl HBr + HO' Br 



j. 



v 



€ 6 H 5 OHBrOHBrOOONa 6 H 5 OHOHOHBrCOOH+NaBr 



€ 6 H 5 - CH:OH Br + NaBr + OO2. 



Quite apart from the general interest of these results 

 the reaction which forms the main subject of this com- 

 munication is obviously of value as affording a greatly 

 improved method for the preparation of phenyl-a-bromo- 

 lactic acid. As far as can be ascertained, the only method 

 hitherto available for this purpose has involved the pro- 

 longed boiling of cinnamic acid dibromide with water; 1 as 

 is well known, this process is vitiated by the formation of 

 appreciable quantities of bromostyrolene and other by- 

 products. 



Phenyl-a-bromolactic acid is of interest because of the 

 ease with which it is converted into phenylacetaldehyde, a 

 substance which, owing to its intense hyacinth odour, is 

 used to some extent in perfumery. The conversion is 

 brought about by treating the phenyl-a-bromolactic acid 

 successively with caustic alkali and dilute sulphuric acid: 2 



€ 6 H 5 OHOHOHBrOOONa + NaOH = 



6 H 5 OHOHOOONa + NaBr+ H 2 0. 



w 



CeHsOHOHOOOH = 6 H 5 CH 2 GHO + 0O 2 . 



w 



It is apparent that the reaction described above facilitates 

 very considerably the preparation of phenylacetaldehyde 

 from cinnamic acid. 



1 Glaser, Liebig's Annalen, vol. 147, p. 84. 

 2 Erlenmeyer and Lipp, Liebig's Annalen, vol. 219, p. 182. 



