Arsenobetaine

Arsenobetaine is an organoarsenic compound found primarily in fish and other marine life, as well as some fungi.^[1][2][3][4] It is the arsenic analog of trimethylglycine, commonly known as betaine. The biochemistry and biosynthesis of this molecule are similar to those of choline and glycine betaine.

Quick facts Names, Identifiers ...

Arsenobetaine

Names
Preferred IUPAC name (Trimethylarsaniumyl)acetate
Identifiers
CAS Number	64436-13-1 Y
3D model (JSmol)	Interactive image Interactive image
Beilstein Reference	3933180
ChEBI	CHEBI:82392
ChEMBL	ChEMBL2448348
ChemSpider	43109 Y
ECHA InfoCard	100.162.654
EC Number	634-697-3
KEGG	C19331 Y
MeSH	Arsenobetaine
PubChem CID	47364
RTECS number	CH9750000
UNII	UWC1LS4V3I
CompTox Dashboard (EPA)	DTXSID0052833
InChI InChI=1S/C5H11AsO2/c1-6(2,3)4-5(7)8/h4H2,1-3H3 N Key: SPTHHTGLGVZZRH-UHFFFAOYSA-N N InChI=1/C5H11AsO2/c1-6(2,3)4-5(7)8/h4H2,1-3H3 Key: SPTHHTGLGVZZRH-UHFFFAOYAQ
SMILES C[As+](C)(C)CC(=O)[O-] C[As+](C)(C)CC([O-])=O
Properties
Chemical formula	C5H11AsO2
Molar mass	177.99/ g.mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H331, H410
Precautionary statements	P261, P264, P270, P271, P273, P301+P310, P304+P340, P311, P321, P330, P391, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Close

Arsenobetaine is a common substance in marine biological systems and unlike many other organoarsenic compounds, such as trimethylarsine, it is relatively non-toxic.^[5][6] The compound may play a similar role as urea does for nitrogen, as a non-toxic waste compound made in the bodies of animals to dispose of the relevant element.

It has been known since 1920 that marine fish contain organoarsenic compounds, but it was not until 1977 that the chemical structure of arsenobetaine was determined.^[7]

Arsenobetaine may be synthesized in the lab from trimethylarsine and ethyl bromoacetate, followed by basic saponification of the resulting ester such as by using a Dowex 2 (HO^-) exchange resin column:^[7]

Me₃As + BrCH₂CO₂Et → Me₃As⁺CH₂CO₂Et + Br⁻

Me₃As⁺CH₂CO₂Et + HO⁻ → Me₃As⁺CH₂CO−2 + EtOH