120977-75-5Relevant academic research and scientific papers
Unbalanced-Ion-Pair-Catalyzed Nucleophilic Fluorination Using Potassium Fluoride
Hammond, Gerald B.,Li, Wangbing,Lu, Zhichao,Xu, Bo
, p. 9640 - 9644 (2021/12/14)
An unbalanced ion pair promoter (e.g., tetrabutylammonium sulfate), consisting of a bulky and charge-delocalized cation and a small and charge-localized anion, greatly accelerates nucleophilic fluorinations using easy handling KF. We also successfully converted an inexpensive and commercially available ion-exchange resin to the polymer-supported ion pair promoter (A26–SO42–), which could be reused after filtration. Moreover, A26–SO42– can be used in continuous flow conditions. In our conditions, water is well-tolerated.
Substitution-reduction: An alternative process for the [ 18F]N-(2-fluoroethylation) of anilines
Briard, Emmanuelle,Pike, Victor W.
, p. 217 - 232 (2007/10/03)
Substitution of a halo atom (chloro or bromo) in easily prepared N-haloacetyl-anilines with no-carrier added (NCA) cyclotron-produced [ 18F]fluoride ion (18F, t1/2 = 109.8 min; β+ = 96.9%), followed by reduction with borane-tetrahydrofuran (BH3-THF), provides an alternative route to NCA [ 18F]N-(2-fluoroethyl)-anilines. This two-step and one-pot process is rapid (～50 min) and moderately high yielding (～40% decay-corrected radiochemical yield (RCY) overall). In the nucleophilic substitution reaction, 18-crown-6 is preferred to Kryptofix 222 as complexing agent for the solubilization of the counter-ion (K+), derived from an added metal salt, in acetonitrile. Weakly basic potassium bicarbonate is preferred as the added metal salt. Inclusion of a small amount of water, equating to 4-5 molar equivalents relative to 18-crown-6, base or precursor (held in equimolar ratio), is beneficial in preventing the adsorption of radioactivity onto the wall of the glass reaction vessel and for achieving high RCY in the nucleophilic substitution reaction. BH3-THF is effective for the rapid reduction of the generated [18F]N-fluoroacetyl-aniline to the [ 18F]N-(2-fluoroethyl)-aniline. Copyright
Electrolytic Reactions of Fluoroorganic Compounds. 14. Regioselective Anodic Methoxylation of N-(Fluoroethyl)amines. Preparation of Highly Useful Fluoroalkylated Building Blocks
Fuchigami, Toshio,Ichikawa,, Shinji
, p. 607 - 615 (2007/10/02)
Anodic methoxylation of various types of N-(fluoroethyl)amines, ArRNCH2Rf (Rf = CF3, CHF2, CH2F, etc.) has been systematically studied and it was found that a methoxy group was exclusively or preferentially introduced into the position α to the fluoromethyl (Rf) group, depending on the Rf and R groups.The effect of the Rf group on the promotion of the anodic α-methoxylation decreased in the order CF3, CHF2, and CH2F.This remarkable promotion effect and unique regioselectivity can be explained mainly in terms of the α-CH kinetic acidities of the cation radicals formed by one-electron oxidation of the amines.The α-methoxylated products are highly useful precursors for the construction of carbon-carbon bonds α to the trifluoromethyl and difluoromethyl groups, which is difficult by other methods.
