4- pyridine hexafluoroantimonate

Fluoropyridinium salts, in most cases, are freely soluble in polar solvents such as acetonitrile, but insoluble or sparingly soluble in nonpolar organic solvents.38 39 The solubilities of 1-fluoro-pyridinium triflate, tetrafluoroborate, hexafluoroantimonate and perchlorate in dichloro-methane are 0.63, 0.05, 0.09 and 0.035 mg cm 3, respectively, and of 1-fluoropyridinium triflate in tetrahydrofuran is 1.71 mg cm-3. The salts were dissolved in water and decomposed very slowly at room temperature. When a solution of 1-fluoropyridinium triflate in water was allowed to stand for 14 days at room temperature it decomposed completely to give pyridin-2-ol in 66% yield. 1-Fluoropyridinium salts with non-nucleophilic counteranions are generally stable crystals with high melting points. 

Fluoropyridinium salts with either tetrafluoroborate, hexafluoroantimonate, or hexafluoro-phosphate as a counteranion can be treated with excess base (triethylamine, pyridine, diethyl-amine) at room temperature to give 2-fluoropyridine (bp 125 126°C, d4° 1.131, np° 1.468) in good yield.43 This method has been successfully applied to the preparation of 2-fluoropyridine derivatives 4 possessing electron-donating or -withdrawing substituents using substituted 1-fluoropyridinium tetrafluoroborates.43... 

Acetylation Acetic anhydride. N-Acetoxyphthalimide. 2- and 3-Acetoxypyridine. Acetyl chloride. N-Acetylimidazole. Boron trifluoride. Catalysts (see Acetic anhydride). Ketene. Magnesium. Methyl oxocarbonium hexafluoroantimonate. Perchloric acid. Phenyl acetate. Pyridine. Sodium acetate. Tetraelhylammonium acetate. p-Toluenesulfonic acid. Tri-n-hexylethyl ammonium hydroxide. 2,4,6-Triisopropylbenzenesulfonyl chloride. Trityl-sodium. Zinc chloride. 

Ci4HigN2Ni02S2, Bis(pyridine)-bis(thioacetato)nickel(II), 42B, 939 Ci4H2oFgFeN2S6, Bis(N,N-diethyldithiocarbamato)(cis-1,2-bis(tri-fluoromethyl)ethylene-1,2-dithiolato)iron, 37B, 629 Ci4H2oF6Fe2S4Sb, M Disulfido-di-M ethyIsulfido-bis(cyclopentadienyl-iron) hexafluoroantimonate, 42B, 939 Cl4H20 6284, Bis(M ethylsulfido)-M disulfido-bis(pentahapto-cyclo-pentadienyliron), 39B, 822... 

Preparation of a 0.025-M solution of (5,5 )-bis(phenyloxazo> linyl)pyridine copper (H) hexafluoroantimonate (87, Scheme 10.20) Dichloromethane (10 mL) was added to a mixture of (S,S)-bis(phenyloxazolinyl)pyridine (92 mg, 0.25 mmol), CuCL (34 mg, 0.25 mmol), and AgSbFe (172 mg, 0.50 mmol) in N2 atmosphere. The resulting mixture was vigorously stirred for 4 hours and filtered through a plug of cotton. The resulting clear blue liquid was used as a 0.025-M solution of catalyst 87. This solution could be kept at ambient temperature for one week without any loss of activity or precipitation. 

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