374 Mr Fenton , Oxidation in Presence of Iron. 
acids with the result that the reaction proves to be a general one, 
that is to say, a large number of ethyl esters may be prepared by 
the use of ethyl ether in place of alcohol, using dry hydrogen 
bromide as dehydrating-agent. 
Characteristic colour reaction for certain carbohydrates. [Fenton 
and Gostling, Trans. Chem. Soc. 1898. 556, and 1901. 361.] Con- 
tinuing the observations upon the action of hydrogen bromide in 
ether on substances other than acids, it was found that certain 
carbohydrates give an intense purple colour with the reagent, and 
that the rapid production of this colour is characteristic of keto- 
hexoses or those containing a ketohexose nucleus. 
Derivatives of Methyl-furfural and the constitution of c celhdose.’ 
[Fenton and Gostling, Trans. Chem. Soc., 1899. 423, and 1901. 
807.] The cause of the remarkable purple colour mentioned in 
the last section was the next subject of enquiry, and after con- 
siderable initial difficulties a new substance was isolated in a 
crystalline state, which proves to be bromo-methyl-furfural, 
HC = C - CH 2 Br 
>° • 
HC=C-CHO 
This substance gives an intense purple colour with hydrogen 
bromide, and on oxidation yields the corresponding bromopyro- 
mucic acid. Later observations shew that the chloro-derivative 
may be produced in a similar manner by the action of hydrogen 
chloride on the carbohydrates mentioned. A large number of 
typical carbohydrates have been investigated, and it is proved that 
these methyl -furfural derivatives result only from ketohexoses 
such as lsevulose and sorbose, or substances which give rise to 
ketohexoses on hydrolysis, such as cane-sugar and inulin. It may 
in fact be stated with confidence that the production of bromo- 
or chloro-methyl-furfural in the manner described is a specific test 
for the presence of a ketohexose nucleus. Later it has been 
shewn that all forms of cellulose give large yields of these methyl 
-furfural derivatives by the action of hydrogen bromide or chloride, 
and the presence in cellulose of a ketohexose nucleus is con- 
sequently proved. After extracting the methyl-furfural derivative 
from the action on cellulose, the residue is found to contain 
ordinary d. glucose ( Proc . Chem. Soc. 1901. 166), a fact of much 
interest in view of the recent isolation of ‘ cellose,’ C^H^On from 
cellulose by Skraup and Konig. 
A large number of other interesting derivatives of methyl 
-furfural have also been obtained by the authors. 
