Tod REPORT—1896. 
has been ascribed by Bender and Schultz (‘ Ber., 19, 3234; 28, 422), and that ofa . 
dinitrososostilbene disulphonic acid 
OH : CH 
CoH,(SO.NaYC ou eS ONA) 
by Fischer and Hepp (‘ Ber.,’ 26, 2231 ; 28, 2281). It had long been known that 
by the action of caustic alkalies upon an alcoholic solution of paranitrotoluene a 
sparingly soluble red condensation product was formed, to which no satisfactory 
formula could be assigned (Klinger, ‘ Ber.,’ 15, 866; 16,941). It was shown by 
Bender and Schultz that this condensation product on reduction gave diamido- 
stilbene whilst curcumine on reduction gave diamidostilbenedisulphonic acid, and 
that hence both products are probably stilbene derivatives. 
In 1888 it was discovered by Bender that by condensing paranitrotoluene sul- 
phonic acid with caustic soda in presence of weak reducing agents such as alcohol, 
glycerol, glucose, &c., colouring-matters were obtained possessing similar properties 
to curcumine, but dyeing redder shades of orange and dissolving in concentrated 
sulphuric acid with a violet or blue colour instead of a red (Eng. Pat. 2664 of 1888). 
It was subsequently found that these colouring-matters (so-called Mikado oranges) 
were also formed by the action of mild reducing agents, such as ferrous hydrate 
upon the primary condensation product (curcumine). 
Neither of the two formule which have been proposed for curcumine gives 2 
satisfactory explanation of its properties and reactions. They afford, for instance, 
no explanation of the dye-stuff character, the great stability towards oxidising 
agents, or of the difficulty of reduction to diamido-stilbene disulphonic acid. Both 
formule are based upon determinations of the quantity of hydrogen required to 
reduce the colour to its leuco compound, to which an hydrazo constitution 
EX: CH. 
EOE ax yy Ca {80,Na) 
is attributed. According to Bender 4 atoms of hydrogen are required, whilst 
Fischer and Hepp find 6 atoms. In order to clear up this discrepancy Bender's 
experiments were repeated exactly according to his directions, but using the free 
acid of,curcumine instead of the sodium salt. In agreement with Bender 4 atoms 
of hydrogen were found to be required. Since, however, the properties of the 
substance in no way correspond with those of an azoxy compound, and the equation 
2C,H,(CH,)(NO,)(SO,Na) = C,,H,N,0(SO,Na), + 3H,0 
would indicate the formation of a body having 2 atoms of hydrogen less than 
Bender’s formula, we have been led to seek another formula more in accordance 
with the facts. 
It may be supposed that the first action of caustic soda upon paranitrotoluene 
sulphonic acid consists in an intramolecular oxidation giving rise to dinitrosostilbene 
disulphonic acid. The two nitrogen atoms may now enter the opposite rings, 
forming an unstable compound— 
N(OH) 
C,H,(S0,Na~ ‘6, H,(80,Na) 
| SN NCO 
| 
nL, 
which, by loss of water, would give rise to curcumine— 
O 
N 
CHSONIE > C.HS0Na) 
