EUDESMIN AND ITS DERIVATIVES. 463 
formed black precipitate on dissolving the diiodo derivative 
in concentrated sulphuric acid, when, however, a brown 
solution is quickly produced as the result of some further 
reaction. 
OXIDATION OF DIBROMEUDESMIN ; FORMATION OF 6-BROMO- 
VERATRIC ACID. 
Dibromeudesmin (5 gr.) was dissolved in hot acetic acid 
and the solution poured into a large volume of cold water. 
The finely divided substance was collected, washed with 
water, and oxidised at about 50° with three per cent. 
aqueous potassium permanganate with continual shaking. 
The oxidation was very slow at first, but soon became more 
rapid, and was discontinued when the amount of unchanged 
substance became relatively small. This point was deter- 
mined by means of tests made from time to time on a 
portion of the well stirred liquid, which was saturated with 
sulphur dioxide until the manganese precipitate dissolved. 
The excess of permanganate was destroyed by sulphurous 
acid and the liquid heated, filtered, concentrated to small 
bulk and acidified whilst hot with hydrochloric acid. On 
cooling, needles separated from the solution and these 
were recrystallised several times from hot water, the first 
solution being decolourised with the aid of animal charcoal. 
The colourless satiny needles melted at 184° and at the 
same temperature when mixed with an equal quantity of 
6-bromoveratric acid which had been prepared by the 
hydrolysis of its methyl ester obtained by the bromination 
of methyl veratrate in acetic acid solution. 
