FD&C Orange Number 1

Orange 1

Names
IUPAC name Sodium 4-[2-(4-oxonaphthalen-1-ylidene)hydrazin-1-yl]benzenesulfonate
Other names Acid orange 20 Orange I FD&C Orange Number 1
Identifiers
CAS Number	523-44-4 4-{2-[(1E)-1-ylidene]-1-yl} Y
3D model (Jmol)	Interactive image
Beilstein Reference	3826844
ChemSpider	7844542 4-{2-[(1E)-1-ylidene]-1-yl} Y 14466524 4-{2-[(1Z)-1-ylidene]-1-yl} Y
ECHA InfoCard	100.007.589
EC Number	208-346-6
PubChem CID	23666138 4-{2-[(1E)-1-ylidene]-1-yl} 23721617 4-{2-[(1Z)-1-ylidene]-1-yl}
RTECS number	DB7085000
InChI InChI=1S/C16H12N2O4S.Na/c19-16-10-9-15(13-3-1-2-4-14(13)16)18-17-11-5-7-12(8-6-11)23(20,21)22;/h1-10,17H,(H,20,21,22);/q;+1/p-1 Y Key: HMWJVUNISIEXFR-UHFFFAOYSA-M Y
SMILES [Na+].[O-]S(=O)(=O)C1=CC=C(NN=C2C=CC(=O)C3=C2C=CC=C3)C=C1
Properties
Chemical formula	C16H11N2NaO4S
Molar mass	350.32 g·mol−1
Hazards
S-phrases (outdated)	S22, S24/25
NFPA 704	0 0 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Orange I

Orange 1 is an organic compound and an azo dye. It is one of the first water soluble dyes to be commercialized, and one of seven original food dyes allowed under the U.S. Pure Food and Drug Act of June 30, 1906. It is derived by the azo coupling reaction of phenyldiazonium and 2,4-diaminotoluene.

At one time it was a popular food colorant but it was delisted in 1959 in the U.S.

In the early 1950s, after several cases were reported of sickness in children who had eaten Halloween candy colored with the dye, the FDA conducted new, more thorough and rigorous testing on food dyes. Orange 1 was outlawed for food use in 1956.