2-pyridyl Ketone Research Articles

ChemInform Abstract: Synthesis of Isopropyl and tert‐Butyl Pyridyl Ketones by Alkylation of Acetylpyridines with Methyl Iodide Using Phase‐Transfer Catalysis.

AbstractThe methyl pyridyl ketones (I) are treated with excess methyl iodide (II) and potassium hydroxide in the presence of a crown ether to produce the isopropyl ketones (III).

A short tetraponerine synthesis

A short synthesis of (±) tetraponerine T4 7 and its “unnatural” isomer 6 from the appropriate pyridyl ketone 1 is described. This synthesis includes an investigation of the stereoselectivity of pyridine reduction in the conversion of the amine 4 to 6 and 7.

ChemInform Abstract: Intramolecular Alkylation of Aromatic Compounds. Part 25. Synthesis of Hexahydro‐7H‐naphtho(1,8‐fg)quinolines and ‐isoquinolines.

AbstractThe pyridyl ketones (IV) and (X), prepared as outlined in the reaction scheme, are subjected to Wolff‐Kishner reduction to give the pyridines (V) and (XI).

Synthesis of Isopropyl and Tert-butyl Pyridyl Ketones by Alkylation of Acetylpyridines with Methyl Iodide Using Phase Transfer Catalysis

Abstract Isomeric acetylpyridines undergo regiospecific alkylation with methyl iodide under solid/liquid phase transfer conditions (aromatic solvent/KOH/18-crown-6) to give the corresponding isopropyl and/or tert-butyl pyridyl ketones, depending on reaction conditions.

ChemInform Abstract: Design and Synthesis of the Chiral Ligands for the Highly Enantioselective Asymmetric Reactions of Carbonyl Compounds

Several chiral ligands were designed and synthesized which perform highly enantioselective asymmetric reactions of carbonyl compounds. Enantioselective reduction of ketones with lithium borohydride modified with N, N'-dibenzoylcystine (or N-benzoylcystein) and tent-butyl alcohol (or ethanol) provided optically active sec.-alcohols in up to 9293% e.e. Functionalized ketones such as α-, β- haloketones, α- and β-aminoketones, pyridyl ketones, and fl-ketoesters were also reduced enantioselectively to afford opticall active epoxides, oxetanes, aminoalcohols, pyridyl alcohols, and β-hydroxyesters in high e.e.'s. Chiral pyrrolidinylmethanols, N, N-dibutylnorephedrine (DBNE), chiral piperazine, and polymer bound N-alkylnorephedrine were efficient chiral catalysts of the enantioselective addition of dialkyl zincs to aldehydes. Alkylation of both aliphatic and aryl aldehydes afforded optically active sec-alcohols in high e.e.'s. Formylesters afforded optically active lactones. Enantioselective conjugate addition of dialkyl zincs to enones was catalyzed by chiral complex prepared from DBNE and Ni (acac) 2 or NiBr2.

ChemInform Abstract: Convenient Synthesis of 3‐Methyl‐1‐(4‐pyridinyl)‐2‐butanone Using Phenyllithium as a Metalating Agent.

3-Methyl-1-(4-pyridinyl)-2-butanone has been synthesized via a short and convenient method based upon acylation of 4-picoline by phenyllithium followed by reaction with ethyl isobutyrate. This procedure can be extended to the preparation of various alkyl pyridyl ketones, intermediates in the synthesis of potential anti-tumor 6-substituted 7H-pyridocarbazole dimers.

Effect of pH on the absorption and emission characteristics of di(3-pyridyl)ketone

The absorption and emission properties of di(3-pyridyl)ketone have been studied in aqueous solution as a function of pH and the p Ks of the nitrogen protonated mono- and di-cations have been spectrophotometrically determined. This molecule exhibits room temperature and low temperature phosphorescence emission of n, π* character in the whole acidity range explored [pH 9/(H 0 − 9)]; triplet lifetime has been measured from the phosphorescence intensity decay. An unusual trend of phosphorescence intensity and lifetime as a function of pH was found and was interpreted as due to hydrogen bond formation with the solvent, whose entity is influenced by both structure breaking of water and protonation of the nitrogen atoms caused by decreasing pH. Experiments carried out in the presence of sodium acetate are described which support this hypothesis. Comparison of the results obtained with those for benzophenone and phenyl(3-pyridyl)ketone allows some generalizations to be drawn about the influence of the heteroatom on the photophysics of ketones.

カルボニル化合物の高エナンチオ選択的不斉反応を目的とする不斉配位子の設計と合成

Several chiral ligands were designed and synthesized which perform highly enantioselective asymmetric reactions of carbonyl compounds. Enantioselective reduction of ketones with lithium borohydride modified with N, N'-dibenzoylcystine (or N-benzoylcystein) and tent-butyl alcohol (or ethanol) provided optically active sec.-alcohols in up to 9293% e.e. Functionalized ketones such as α-, β- haloketones, α- and β-aminoketones, pyridyl ketones, and fl-ketoesters were also reduced enantioselectively to afford opticall active epoxides, oxetanes, aminoalcohols, pyridyl alcohols, and β-hydroxyesters in high e.e.'s. Chiral pyrrolidinylmethanols, N, N-dibutylnorephedrine (DBNE), chiral piperazine, and polymer bound N-alkylnorephedrine were efficient chiral catalysts of the enantioselective addition of dialkyl zincs to aldehydes. Alkylation of both aliphatic and aryl aldehydes afforded optically active sec-alcohols in high e.e.'s. Formylesters afforded optically active lactones. Enantioselective conjugate addition of dialkyl zincs to enones was catalyzed by chiral complex prepared from DBNE and Ni (acac) 2 or NiBr2.

Photometric and fluorimetric methods for the determination of bromate in bread

Kinetic methods for the determination of bromate based on the oxidation of benzyl 2-pyridyl ketone 2-quinolylhydrazone are described. The initial reaction rate is linearly related to the bromate concentration with detection limits of 0.25–6.50 µg ml–1 for photometric monitoring and 0.08–5.20 µg ml–1 when the change in the fluorescence signal is measured. Under appropriate working conditions, the photometric method was applied satisfactorily to the determination of bromate in bread.

Alkylation of 2-azaallyl anions; a versatile primary amine synthesis

Imines from primary amines and mesityl 2-pyridyl ketone react with LDA followed by treatment with an alkyl halide and hydrolysis to give the original amine alkylated at the alpha-position.

Fungicidal activity of a series of phenyl pyridyl ketoximes and their O‐acetyl derivatives

AbstractThe free oximes and acetyl derivatives of a series of 4‐substituted phenyl pyridyl ketones were prepared and tested in vitro and in vivo against fungal plant pathogens of different taxonomic classes.All compounds exhibited an interesting activity against some or all of the test fungi. The best results were given by the acetyl derivatives.

Fungizide Pyridinderivate I: α-Trichlormethyl-3-pyridinmethanole

The title substances, a new type of compounds with fungicidal activity, were synthesized by addition of trichloromethyllithium (and tribromomethyllithium resp.) to various 3-pyridyl ketones at −100°C.

Convenient synthesis of 3‐methyl‐1‐(4‐pyridinyl)‐2‐butanone using phenyllithium as a metalating agent

Abstract3‐Methyl‐1‐(4‐pyridinyl)‐2‐butanone has been synthesized via a short and convenient method based upon acylation of 4‐picoline by phenyllithium followed by reaction with ethyl isobutyrate. This procedure can be extended to the preparation of various alkyl pyridyl ketones, intermediates in the synthesis of potential anti‐tumor 6‐substituted 7H‐pyridocarbazole dimers.

Spectrophotometric determination of hydroxylamine using the DPGH-iron(II)-NH 2OH ternary complex

Iron(II) reacts with di(2-pyridyl)ketone guanylhydrazone in ammonia medium to form a yellow complex. This complex is decolorized by the addition of sodium hydroxide but in the presence of hydroxylamine a stable blue-colored complex is formed. Based on these properties a method was developed for the spectrophotometric determination of hydroxylamine in the presence of other reducing substances.

Allenes. Part 47. Pyrido[1,2-a]pyrimidines and their hydrolysis products from allenic and acetylenic nitriles

The reactions between 2-aminopyridine, C-substituted 2-aminopyridines, and allenic nitriles or phenylpropynenitrile give, initially, 2-amino-2H-pyrido[1,2-a]pyrimidines which are moderately stable under acidic conditions but undergo addition of water with extreme ease under basic conditions to form 4-hydroxypyrido[1,2-a]pyrimidines. These undergo ring cleavage when refluxed in ethanol to pyridyl ketones (5).

The inhibition of bovine herpesvirus-1 by methyl 2-pyridyl ketone thiosemicarbazone and its effects on bovine cells

Methyl 2-pyridyl ketone thiosemicarbazone (MPKT) was found to inhibit bovine herpesvirus-1 (BHV-1) at an ED 50 concentration of approximately 5–10 μM. Several virus strains were shown to have similar sensitivity to the drug and serial passage of virus in the presence of MPKT failed to yield resistant progeny. There was evidence for toxic effects on cells at drug concentrations similar to those required to inhibit virus and passage of cells in low concentrations of MPKT gave results suggesting cumulative toxicity. Pre-incubation of cells in the presence of MPKT produced a residual antiviral effect. Taken together, these observations cast doubt on the selectivity of the drug for BHV-1, at least in the bovine system under test.

Structures of O-palmitoyl benzophenone oxime (I) and (E)-O-palmitoyl phenyl 2-pyridyl ketone oxime (II)

Structures of O-palmitoyl benzophenone oxime (I) and (E)-O-palmitoyl phenyl 2-pyridyl ketone oxime (II)

Ternary complexes of substituted catechols and catecholamines

Stability constants of the ternary complexes [CuAL] whereA = 5-Nitro-1,10-phenanthroline, bis(2-pyridyl) ketone (DPK) orbis(2-pyridyl)amine (DPA) andL is the dianion of catechol, tiron, protocatechic acid, pyrogallol, 1,8-dihydroxynaphthalene, catecholaldehyde, 2,3-dihydroxynaphthalene, dopamine or adrenaline have been determined by potentiometric titration in dioxane water (1:1 v/v) medium using a SCOGS computer programme. The observed trend of stability is explained on the basis of the nature of substitution over the ligands, chelate ring size and also the composition of mixed solvent in case of DPK. Structural changes in DPK have also been discussed as a function of pH, composition of medium and coordinating mode of the secondary ligand in the ternary complexes.

Fluorimetric and absorptiometric determination of dissociation constants and chromogenic reactions of benzyl 2-pyridyl ketone 2-quinolylhydrazone

The dissociation constants in the ground state of benzyl 2-pyridyl ketone 2-quinolylhydrazone (BPKQH) have been determined fluorimetrically and spectrophotometrically in aqueous ethanol medium. The p K a values of this compound in the excited state have also been established. The analytical properties of the reagent and its chromogenic reactions with some metal ions were studied.

METAL-CATALYZED SYNTHESIS OF CARBOXYLIC ESTERS UTILIZING (E)-PHENYL 2-PYRIDYL KETONE O-ACYLOXIMES (PPAO)

Abstract (E)-phenyl 2-pyridyl ketone O-acyloximes (PPAO) could be highly activated by metal ions such as Fe3+, Cu2+, and Zn2+, and the most effective catalyst for the synthesis of carboxylic esters was found to be Zn2+. Furthermore, sterically hindered carboxylic esters were easily obtained utilizing PPAOs and alcoholates in high yields.