2-Fluoroethanol is the
organic compound with the formula CH2FCH2OH. This colorless liquid is one of the simplest stable fluorinated alcohols. It was once used as a
pesticide. The related difluoro- and trifluoroethanols are far less dangerous.[4]
Synthesis
2-Fluoroethanol was originally synthesized by treating
2-chloroethanol with
potassium fluoride, in a simple
Finkelstein reaction.[5] The product has a lower boiling point that the starting material and may be conveniently isolated by distillation.
ClCH2CH2OH + KF → FCH2CH2OH + KCl
Similar procedures start from (1,3)-dioxolan-2-one[6] and from
2-bromoethanol.[7]
2-[18F]-fluoroethoxy group is a common moiety in the structures of radiotracers used with PET. Such radiotracers include
fluoroethyl-l-tyrosine 1-(2-[18F]-fluoroethoxy)-4-nitrobenzene and [18F]-fluoroethyl 4-fluorobenzoate, being a [18F]fluoroalkyl ether and ester respectively.[12][11]
Metabolism
It was patented as a rodenticide in Germany in 1935.[13] In rats, it was found that fluoroethanol induced a similar toxicity as that of
fluoroacetate, known to metabolize to
fluorocitrate to exert the toxic effect.[13]
Fluoroacetate is a precursor to fluorocitrate,[14] an inhibitor of
aconitase, an enzyme that participates in the TCA cycle.[15]
Toxicity
Reported effects of 2-fluoroethanol are
epigastric distress effects, such as vomiting, and
central nervous effects, such as auditory hallucinations, numbness feeling of the face or nose. Both these types of effects occur gradually after being exposed to 2-fluoroethanol for several hours. Some more severe reactions of the human body to 2-fluoroethanol can be
respiratory failure and epileptiform convulsions or
seizures, leading to dysfunctions in the heart mechanism. From the early 20th century, there are multiple reports of deaths caused by 2-fluoroethanol.[16]
2-Fluoroethanol is also toxic to other animals with LD50 ranging from 7 to 1500 mg/kg bodyweight.
^Gergel, Max G. (March 1977). Excuse me sir, would you like to buy a kilo of isopropyl bromide?. Pierce Chemical. p. 92, which also opines that "By the time you have established this [odor] you have probably had a fatal exposure, unless, like Max Gergel circa 1945—you have a hyperactive liver."
^Hoffmann, Friedrich W. (1948). "Preparation of Aliphatic Fluorides". Journal of the American Chemical Society. 70 (7): 2596–2597.
doi:
10.1021/ja01187a505.
PMID18875124.
^Shahak, Israel; Bergmann, Ernst D. (1965). "A convenient of synthesis β- and γ-fluoro-alcohols". Chem. Commun. (7): 122a.
doi:
10.1039/c1965000122a.
^Bhadury, Pinaki S.; Raza, Syed K.; Jaiswal, Devendra K. (1999). "A semi-molten mixture of hexadecyltributylphosphonium bromide and potassium fluoride in the synthesis of organofluorine compounds". Journal of Fluorine Chemistry. 99 (2): 115–117.
Bibcode:
1999JFluC..99..115B.
doi:
10.1016/s0022-1139(99)00121-9.
^Huang, Jinfan; Hedberg, Kenneth (1989). "Conformational analysis. 13. 2-Fluoroethanol. An investigation of the molecular structure and conformational composition at 20, 156, and 240.degree.. Estimate of the anti-gauche energy difference". Journal of the American Chemical Society. 111 (18): 6909–6913.
doi:
10.1021/ja00200a003.
^Dixon, David A.; Smart, Bruce E. (1991). "Conformational energies of 2-fluoroethanol and 2-fluoroacetaldehyde enol: Strength of the internal hydrogen bond". The Journal of Physical Chemistry. 95 (4): 1609–1612.
doi:
10.1021/j100157a020.
^
abFalzon, C. L., Ackermann, U., Spratt, N., Tochon-Danguy, H. J., White, J., Howells, D., & Scott, A. M. (2006).F-18 labelledN,N-bis-haloethylamino-phenylsulfoxides — a new class of compounds for the imaging of hypoxic tissue. Journal of Labelled Compounds and Radiopharmaceuticals, 49(12), 1089–1103.
https://doi.org/10.1002/jlcr.1129
^Pan, J., Pourghiasian, M., Hundal, N., Lau, J., Bénard, F., Dedhar, S., & Lin, K.-S. (2013). 2-[18F]-fluoroethanol and 3-[18F]-fluoropropanol: facile preparation, biodistribution in mice, and their application as nucleophiles in the synthesis of [18F]fluoroalkyl aryl ester and ether PET tracers. Nuclear Medicine and Biology, 40(6), 850–857.
https://doi.org/10.1016/j.nucmedbio.2013.04.009
^Goncharov, N. V., Jenkins, R. O., & Radilov, A. S. (2006). Toxicology of fluoroacetate: a review, with possible directions for therapy research. Journal of applied toxicology : JAT, 26(2), 148–161.
https://doi.org/10.1002/jat.1118
^Timbrell, J. A. (2008). Principles of Biochemical Toxicology (Fourth Edition). Taylor & Francis. p. 358-359.