syn-Propanethial-S-oxide facts for kids

syn-Propanethial S-oxide
IUPAC name	(Z)-propylidene-λ4-sulfanone
Other names	Thiopropanal S-oxide 1-Sulfinylpropane
Identifiers
CAS number	32157-29-2
PubChem	441491
SMILES	O=S=C/CC
InChI InChI=1/C3H6OS/c1-2-3-5-4/h3H,2H2,1H3
Properties
Molecular formula
Molar mass	0 g mol-1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

syn-Propanethial S-oxide (or (Z)-propanethial S-oxide), a member of a class of organosulfur compounds known as thiocarbonyl S-oxides (formerly "sulfines"), is a volatile liquid that acts as a lachrymatory agent (triggers tearing and stinging on contact with the eyes). The chemical is released from onions, Allium cepa, as they are sliced. The release is due to the breaking open of the onion cells and their releasing enzymes called alliinases, which then break down amino acid sulfoxides, generating sulfenic acids. A specific sulfenic acid, 1-propenesulfenic acid, formed when onions are cut, is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase or LFS, giving syn-propanethial S-oxide. The gas diffuses through the air and, on contact with the eye, it stimulates sensory neurons creating a stinging, painful sensation. Tears are released from the tear glands to dilute and flush out the irritant. A structurally related lachrymatory compound, syn-butanethial S-oxide, C₄H₈OS, has been found in another genus Allium plant, Allium siculum.

See also

In Spanish: Sulfóxido de tiopropanal para niños