Thenoyltrifluoroacetone

Thenoyltrifluoroacetone^[1]

Names
IUPAC name 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione
Other names 2-thenoyltrifluoroacetone
Identifiers
CAS Number	326-91-0
ChemSpider	5399
DrugBank	DB04795
Jmol interactive 3D	Image
PubChem	5601
InChI InChI=1S/C8H5F3O2S/c9-8(10,11)7(13)4-5(12)6-2-1-3-14-6/h1-3H,4H2 Key: TXBBUSUXYMIVOS-UHFFFAOYSA-N InChI=1/C8H5F3O2S/c9-8(10,11)7(13)4-5(12)6-2-1-3-14-6/h1-3H,4H2 Key: TXBBUSUXYMIVOS-UHFFFAOYAR
SMILES O=C(c1sccc1)CC(=O)C(F)(F)F
Properties
Chemical formula	C8H5F3O2S
Molar mass	222.18 g mol^−1
Appearance	fine, slightly yellow crystals
Melting point	40 to 44 °C (104 to 111 °F; 313 to 317 K)
Boiling point	96 to 98 °C (205 to 208 °F; 369 to 371 K) 8 mmHg
Hazards
Main hazards	Xi
R-phrases	R36/37/38
S-phrases	S26 S27 S28 S29 S30 S33 S35 S36
Flash point	12 °C (54 °F; 285 K) (closed cup)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Thenoyltrifluoroacetone, C₈H₅F₃O₂S, is a chemical compound used pharmacologically as a chelating agent. It is an inhibitor of cellular respiration by blocking the respiratory chain at complex II.

Perhaps the first report of TTFA as an inhibitor of respiration was by A. L. Tappel in 1960.^[2] Tappel had the (erroneous) idea that inhibitors like antimycin and alkyl hydroxyquinoline-N-oxide might work by chelating iron in the hydrophobic milieu of respiratory membrane proteins, so he tested a series of hydrophobic chelating agents. TTFA was a potent inhibitor, but not because of its chelating ability. TTFA binds at the quinone reduction site in Complex II, preventing ubiquinone from binding. The first x-ray structure of Complex II showing how TTFA binds, 1ZP0, was published in 2005 .^[3]

References

1. Sigma-Aldrich product page
2. Tappel (July 1960). "Inhibition of electron transport by antimycin A, alkyl hydroxy naphthoquinones and metal coordination compounds". Biochem. Pharmacol. 3: 289–96. doi:10.1016/0006-2952(60)90094-0. PMID 13836892.
3. "Crystal Structure of Mitochondrial Respiratory Membrane Protein Complex II". Cell 121 (7): 1043–1047. 2005. doi:10.1016/j.cell.2005.05.025. PMID 15989954.