Tobias acid

Tobias acid (2-amino-1-naphthalenesulfonic acid) is an organic compound with the formula C₁₀H₆(SO₃H)(NH₂). It is named after the German chemist Georg Tobias.^[1] It is one of several aminonaphthalenesulfonic acids, which are derivatives of naphthalene containing both amine and sulfonic acid functional groups. It is a white solid, although commercial samples can appear otherwise.^[2] It is used in the synthesis of azo dyes such as C.I. Acid Yellow 19 and C.I. Pigment Red 49. It is prepared via the Bucherer reaction of 2-hydroxynaphthalene-1-sulfonic acid with ammonia and ammonium sulfite.^[3]

Tobias acid

Names
Preferred IUPAC name 2-Aminonaphthalene-1-sulfonic acid
Other names 2-Naphthylamine-1-sulfonic acid
Identifiers
CAS Number	81-16-3
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL3182507
ChemSpider	6418
ECHA InfoCard	100.001.211
EC Number	201-331-5
PubChem CID	6670
UNII	F9QKW1FCE0
CompTox Dashboard (EPA)	DTXSID7020922
InChI InChI=1S/C10H9NO3S/c11-9-6-5-7-3-1-2-4-8(7)10(9)15(12,13)14/h1-6H,11H2,(H,12,13,14) Key: GWIAAIUASRVOIA-UHFFFAOYSA-N
SMILES C1=CC=C2C(=C1)C=CC(=C2S(=O)(=O)O)N
Properties
Chemical formula	C10H9NO3S
Molar mass	223.25 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references