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A derivative of trifluorotoluene, 3-aminobenzotrifluoride, is the precursor to the herbicide fluometuron. [3] It is synthesized via nitration followed by reduction to meta-H 2 NC 6 H 4 CF 3. This aniline is then converted to the urea. Flumetramide (6-[4-(trifluoromethyl)phenyl]morpholin-3-one), a skeletal muscle relaxant, is also prepared from ...
The first to investigate trifluoromethyl groups in relationship to biological activity was F. Lehmann in 1927. [5] An early review appeared in 1958. [6] An early synthetic method was developed by Frédéric Swarts in 1892, [7] based on antimony fluoride. In this reaction benzotrichloride was reacted with SbF 3 to form PhCF 2 Cl and PhCF 3.
The sulfonyl chlorides and fluorides are of dominant importance in this series. [1] [2] Sulfonyl halides have tetrahedral sulfur centres attached to two oxygen atoms, an organic radical, and a halide. In a representative example, methanesulfonyl chloride, the S=O, S−C, and S−Cl bond distances are respectively 142.4, 176.3, and 204.6 pm. [3]
For example, n-butyl triflate can be written as CH 3 CH 2 CH 2 CH 2 OTf. The corresponding triflate anion, CF 3 SO − 3, is an extremely stable polyatomic ion; this comes from the fact that triflic acid (CF 3 SO 3 H) is a superacid; i.e. it is more acidic than pure sulfuric acid, already one of the strongest acids known.
Fluorobenzenes are a group of aryl fluorides/halobenzenes consisting of one or more fluorine atoms as substituents on a benzene core. They have the formula C 6 H 6–n F n, where n = 1–6 is the number of fluorine atoms.
The modest acidity of carbons adjacent to the sulfonyl group has made sulfones useful for organic synthesis. Upon removal of the sulfonyl group with desulfonylation or reductive elimination, the net result is the formation of a carbon-carbon bond single or double bond between two unfunctionalized carbons, a ubiquitous motif in synthetic targets.
Its pK a value in water cannot be accurately determined but in acetonitrile it has been estimated as −0.10 and in 1,2-dichloroethane −12.3 (relative to the pK a value of 2,4,6-trinitrophenol (picric acid), anchored to zero to crudely approximate the aqueous pK a scale [2]), making it more acidic than triflic acid (pK a MeCN = 0.70, pK a DCE ...
However, the use of dichloromethane is avoided since it can generate highly explosive azido-chloromethane and diazidomethane. The reaction may also instead be conducted in toluene, [3] acetonitrile, or pyridine. [4] Tf 2 O + NaN 3 → TfN 3 + NaOTf (Tf = CF 3 SO 2) An alternative route starts from imidazole-1-sulfonyl azide. [5]