Acetylation pyridine

According to U.S. Patent 2,966,493, the 2,3-bis-(3-pyridyl)-2,3-butanedlol used as the starting material may be prepared as follows. A solution of 1,430 g of 3-acetyl-pyridine in 7,042 ml of a 1 N aqueous solution of potassium hydroxide is placed into a cathode chamber containing a mercury cathode with a surface of 353 cm and is separated from an anode chamber by an Alundum membrane. As anode a platinum wire is used and the anolyte consists of a 1 N solution of aqueous potassium hydroxide which Is replenished from time to time. 

The effectiveness of ylides in the field of polymer science was first described in 1966 by George et al. [11] who felt that 3- and 4-(bromo acetyl) pyridines, which contain both the a-haloketone and the pyridine nucleus in a single molecule, could be quaternized to polymeric quaternary salts and finally to polymeric ylides Schemes 9 and 10 by treating these polymeric salts with a base. 

Werden prochirale Ketone (Acetyl-pyridine, Benzoyl-Verbindungen) in Gegenwart optisch aktivier Ephedrinium-Salze elektrolysiert, so bilden sich die jeweils anderen Enan-tiomere des sekundaren Alkohols im (JberschuB6. 

Acetyl-pyridine werden (ahnlich wie Acetophenon) bei Anwesenheit optisch aktiver Alkaloide in Athanol/waBr. Acetatpuffer (1 1) bei —0,7 bis —0,8 V an Quecksilber zu den entsprechenden Alkoholen reduziert. In Gegenwart von Strychnin wird 1-Pyridyl-(2)-athanol zu 50% d.Th. (47,5% opt. Ausbeute) 1 -Pyridyl-(4)-dthanol zu 40% d.Th. (40% opt. Ausbeute) gebildet. Mit Brucin sind die optischen Ausbeuten stets deutlich ge-ringer (max. 27%)- Aus 3-Acetyl-pyridin entsteht stets das inaktive l-Pyridyl-(3)-athanol (40% d.Th.)2. 

An einer Graphit-Kathode erhalt man (-1,1 V) aus 4-Acetyl-pyridin 90% d.Th. 1-Py-ridyl-(4)-dthanol, das (-)-Enantiomere ist jedoch nur mit 2% (JberschuB vorhanden . 

While iron(III) complexes of thiosemicarbazones with different functional groups involving have been prepared from 2-acetylpyridine, substitution on the ring has been more popular with thiosemicarbazones derived from 2-formylpyridine. The only thiosemicarbazones in which the 2-acetylpyridine ring has been substituted are 15a and 15b, prepared from 6-methyl-2-acetyl-pyridine [120]. Both of these iron(III) complexes have rhombic spectra and values of g, are similar to those found for the 2-acetylpyridine thiosemicarbazones. Solution studies have been carried out on the iron(III) complex of 2,6-diacetylpyridine mono-thiosemicarbazone, but the solid complex was not isolated [143]. 

Other condensations were described using pyridin-2-ones instead of 2-chloropyridines, but they need to be rendered more electrophilic by iV-acylation. Thus, the reaction of iV-acetyl pyridin-2-one 200 with hydrazine led to 201 (Equation 22) <2003PS1129>. Similarly, the intramolecular cyclization of 202 afforded the pyridotriazolone 203 (Equation 23) <1995JIC735>. 

A range of chiral alkaloids have been screened for the asymmetric reduction of 2- and 4-acetyl pyridine [41] and results are given in Table 10.5. Brucine and strychnine give the highest enantiomeric excess in the pyridinylethanols produced. Reduction of 3-acetylpyridine however affords no optically active alcohol under all conditions employed. A further effect of the added alkaloid is to raise the yield of secondary alcohol at the expense of the pinacols relative to reactions where no alkaloid is present. The high enantiomeric excess found during reduction of 4 ... 

Enantiomeric excess in pyridinylethanols from reduction of 2- and 4-acetyl-pyridine at mercury. The electrolyte contains an alkaloid (5 x 10 M) in aqueous acetate buffer (pH 4.5) - ethanol (1 1) at 0° C. Data from ref. [41]. 

Miller and his co-workers60) reported surprisingly high optical yields, close to 50 %, in the reduction of 2-acetylpyridine in the presence of strychnine. They also prepared chemically modified electrodes with optically active amino acids and attempted asymmetric induction in both reduction and oxidation61 . The best optical yield, only 14.5 %, seemed to be obtained in the reduction of 4-acetyl-pyridine on a graphite cathode modified with (S)-phenylalanine methyl ester. 

A. 4-Aaetylpyridine oxime. Hydroxyl amine hydrochloride (25.0 g, 0.36 mol) (Note 1) is dissolved in 50 mL of water, and the solution 1s added to 70 mL of 20K aqueous sodium hydroxide in a 500-mL Erlenmeyer flask. To this magnetically stirred solution 1s added at one time 4-acetyl pyridine (36.3 g, 0.30 mol) (Note 2) a precipitate forms rapidly. The reaction mixture is stirred at 0-5°C for 2 hr then the precipitate is collected by suction filtration and washed with 500 mL of cold water. 

Acetyl pyridine (98%) from Aldrich Chemical Company, Inc. was distilled under reduced pressure (bp 103-104°C/14-16 mm) prior to use. 

Hydroxylamine hydrochloride (8) Hydroxyl amine, hydrochloride (9) (5470-11-1) 4-Acetyl pyridine oxime Ketone, methyl 4-pyridyl oxime (8) Ethanone, l-(4-pyridinyl)- oxime (9) (1194-99-6)... 

Acetyl pyridine oxime tosylate Ethanone, l-(4-pyridinyl)-0-[(4-methylphenyl)sulfonylloxime (10) (74209-52-2)... 

The model had been substantiated by measuring the potential dependent electrosorption isotherms of all species involved that show that the proto-nated alcaloids are those species that are by far most strongly adsorbed, whereas the acetyl pyridines are least strongly adsorbed, especially at lower pH relative to the electrosynthesis, which is performed at pH 4 to 4.5. The optically inductive reduction of 2- and 4-acetyl pyridine to the optically active carbinols demands the formation of a dense but not too densely packed surface layer of adsorbed protonated alcaloid, which still allows for insertion of the oxo-compound or the ketyl radical, respectively. Performing the reaction with too high alcaloid concentrations leads to compaction on the adsorbate layer, the ketyl radical is squeezed out, and optimal induction is no longer observed. 

Other dicarbonyl components, widely used in the examined syntheses, are 2,6-diformyl(acetyl)pyridines, for instance (3.161) [318] ... 

The strength of the basic compounds pKb in engine oil estimated in glacial acetic acid is from 11 to 12.5 units in water scale (see Fig. 6.6). Also, it has been proved that 2,4,6-trimethylpyridine, pKb(H20) = 6.68, applied as a reference in the ASTM D664 emf technique to obtain the inflection point on the badly developed titration curves, is too strong of a base (Pawlak, 1980) and should be replaced by the base having pKb(H20) about 11, e.g., 2-chloroaniline, pyrazole, or 3-acetyl-pyridine. 

Reaction of [Ru(NH3)4(OH2)2]2+ with L (L = 2-pyridine carboxaldehyde,263 2-pyridine alcohol4763) yields the complexes [RuuL(NH3)4]2+. These products can be interconverted by oxidation of the pyridine alcohol derivative (48) to the acetyl pyridine complex (49) (Scheme 18) 4763 The complexes [Ru(NH3) L]+ (n = 4,5 LH = pyrazinecarboxylic acid) have been generated in which L can be mono- or bi-dentate.476b... 

A series of 4-aryl-6-(l//-indol-3-yl)-2,2-bipyridine-5-carbonitriles 9 was synthesized by Perumal and co-workers [60] via a one-pot MCR of an aromatic aldehyde, a 3-(cyanoacetyl)indole, 2-acetyl pyridine and ammonium acetate by microwave irradiation under solvent-free conditions. The compounds were obtained in high yields and in a very short period of time as compared to conventional heating. Remarkably, when 2,4-dichlorobenzaldehyde was used in this reaction, only the Hantzsch 1,4-dihydropyridine was isolated which had to be separately dehydrogenated to get the targeted pyridine (Scheme 9). 

They utilized the reaction between indole Grignard reagents and either 3-acetyl-pyridine or nicotinoyl chloride to give the target structures 54 and 365, after the appropriate reduction. None of these compounds displayed antitumor activity anywhere comparable to that of ellipticine. 

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