Atoxyl

Arsanilic acid

Names
IUPAC name 4-aminophenylarsonic acid
Other names 4-Aminobenzenearsonic acid, 4-Aminophenylarsonic acid, 4-Arsanilic acid, Atoxyl
Identifiers
CAS Number	98-50-0 N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:49477 Y
ChemSpider	7111 Y
DrugBank	DB03006 Y
ECHA InfoCard	100.002.432
PubChem CID	6432805
UNII	UDX9AKS7GM N
InChI InChI=1S/C6H8AsNO3/c8-6-3-1-5(2-4-6)7(9,10)11/h1-4H,8H2,(H2,9,10,11) Y Key: XKNKHVGWJDPIRJ-UHFFFAOYSA-N Y InChI=1/C6H8AsNO3/c8-6-3-1-5(2-4-6)7(9,10)11/h1-4H,8H2,(H2,9,10,11) Key: XKNKHVGWJDPIRJ-UHFFFAOYAQ
SMILES O=[As](O)(O)c1ccc(N)cc1
Properties
Chemical formula	C6H8AsNO3
Molar mass	217.054 g/mol
Appearance	white solid
Density	1.957 g/cm3
Melting point	232 °C (450 °F; 505 K)
Solubility in water	modest
Hazards
Main hazards	Toxic
R-phrases	R23-R25,R50-R53 23/25-50/53
S-phrases	S20S21S28S45S60-S61
NFPA 704	0 2 0
Related compounds
Related compounds	phenylarsonic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Arsanilic acid, also known as aminophenyl arsenic acid or aminophenyl arsonic acid, is an organoarsenic compound, an amino derivative of phenylarsonic acid whose amine group is in the 4-position. A crystalline powder introduced medically in the late 19th century as Atoxyl, its sodium salt was used by injection in the early 20th century as the first organic arsenical drug, but it was soon found prohibitively toxic for human use.

Arsanilic acid saw long use as a veterinary feed additive promoting growth and to prevent or treat dysentery in poultry and swine. In 2013, its approval by US government as an animal drug was voluntarily withdrawn by its sponsors. Still sometimes used in laboratories, arsanilic acid's legacy is principally through its influence on Paul Ehrlich in launching the chemotherapeutic approach to treating infectious diseases of humans.

Synthesis was first reported in 1863 by Antoine Béchamp and became the basis of the Bechamp reaction. The process involves the reaction of aniline and arsenic acid via a electrophilic aromatic substitution reaction.

Arsanilic acid occurs as a zwitterion, H₃N⁺C₆H₄AsO₃H⁻, yet is typically represented with the non-zwitterionic formula H₂NC₆H₄AsO₃H₂.

Since at least 2000 BC, arsenic and inorganic arsenical compounds were both medicine and poison. In the 19th century, inorganic arsenicals became the preeminent medicines, for instance Fowler's solution, against diverse diseases.

In 1859, in France, while developing aniline dyes,Antoine Béchamp synthesized a chemical that he identified, if incorrectly, as arsenic acid anilide. Also biologist, physician, and pharmacist, Béchamp reported it 40 to 50 times less toxic as a drug than arsenic acid, and named it Atoxyl, the first organic arsenical drug.