New chromogens of the ferroin-type-IV Oximes of substituted methyl and phenyl 2-pyridyl ketones

The spectral characteristics, and solution conditions requisite for formation, of the iron(II), cobalt(II), and copper(I) chelates of some newly synthesized oximes containing the ferroin functional grouping have been determined. For some of the oximes, both syn- and anti-isomers were available for study. NMR spectra of the isomers differed, enabling structural distinctions to be made. None of the anti-isomers formed coloured metal chelates. A practical method for distinguishing between the isomers can be based on these findings. Two of the compounds proved very promising as highly sensitive chromogens for determining iron in strongly alkaline materials.     

Synthesis of functionalized 3-hydroxypiperidines

The synthetic versatility of three chemoenzymatically prepared hydroxypiperidine building blocks has been explored, resulting in a library of enantiopure functionalized piperidines. Key steps involved N-acyliminium ion-mediated CC-bond formation and cross-metathesis reactions, after which full deprotection led to the set of free 3-hydroxypiperidines.     

Synthesis of functionalized dialkyl ketones from carboxylic acid derivatives and alkyl halides

Unsymmetrical dialkyl ketones can be directly prepared by the nickel-catalyzed reductive coupling of carboxylic acid chlorides or (2-pyridyl)thioesters with alkyl iodides or benzylic chlorides. A wide variety of functional groups are tolerated by this process, including common nitrogen protecting groups and C-B bonds. Even hindered ketones flanked by tertiary and secondary centers can be formed. The mechanism is proposed to involve the reaction of a (L)Ni(alkyl)(2) intermediate with the carboxylic acid derivative.     

Palladium-catalyzed asymmetric hydrogenation of functionalized ketones

[reaction: see text]. A novel catalytic system for asymmetric hydrogenation of functionalized ketones has been developed using a Pd/bisphosphine complex as the catalyst in 2,2,2-trifluoroethanol. The reaction exhibits high enantioselectivity, and up to 92.2% ee was obtained.     

Synthesis of 3-fluoroalkyl-2-aziridinyl ketones

Simple and efficient methods for the synthesis oftrans-3-fluoroalkyl-2-aziridinyl ketones from polyfluorinated α,β-enones have been developed.     

Synthesis and properties of bis(heteroazulen-3-yl)methyl cations and bis(heteroazulen-3-yl)ketones

The synthesis and properties of a novel type of bis(heteroazulen-3-yl)methyl cations, bis(2-oxo-2H-cyclohepta[b]furan-3-yl)methyl cation salt and nitrogen analogues, (9a-c·PF₆⁻) and (9a-c·BF₄⁻), as well as bis(heteroazulen-3-yl)ketones (12a-d) are studied. The synthetic method was based on a TFA-catalyzed electrophilic aromatic substitution on the heteroazulenes (6a-d) with paraformaldehyde to afford the corresponding disubstituted methane derivatives 7a-d, followed by oxidative hydrogen abstraction with DDQ, and subsequent exchange of the counter-anion by using aq. HPF₆ or aq. HBF₄. In addition, the reaction of 7a-d with 2.2 equiv. amounts of DDQ afforded carbonyl compounds 12a-d. The delocalization of the positive charge of 9a-c was evaluated by the ¹H and ¹³C NMR spectral data. The thermodynamic stability of cations 9a-c was evaluated to be in the order 9a<9b<9c on the basis of their reduction potentials measured by cyclic voltammetry (CV) and pK_R+ values (2.6-10.3) obtained spectrophotometrically. The reduction waves of cations 9a-c were irreversible, suggesting the dimerization of the radical species generated by one-electron reduction. This was demonstrated by the reduction of 9a·BF₄⁻ with Zn powder to give dimerized product 14a. In addition, the quenching of 9a·BF₄⁻ with MeOH/NaHCO₃ gives ether derivative 15a, which is proposed for the precursor for synthesizing tris(heteroazulene)-substituted methyl cations bearing two different heteroazulene-units.     

Synthesis of functionalized fluorine-containing hyperbranched poly(aryl ether ketones) for optical applications

Hyperbranched poly(aryl ether ketones) with terminal fluorine atoms (OH: F = 0.48: 1.00) or hydroxyl groups (OH: F = 2.02: 1.00) have been obtained through the polycondensation of bis(4,4′-dihydroxydiphenyl-2,2-hexafluoropropane) with 1,3,5-tris[4-(4-fluorobenzoyl)phenoxy]benzene in tetramethylene sulfone. Both polymers have M _n = (7.1?7.3) × 10³ and M _w = (8.4?8.8) × 10³ and are transparent in the near-IR region, in particular, at 1.30 and 1.55 μm.     

Synthesis of 6-hydroxytetrahydro-1,3-thiazine-2-thiones and methyl esters of 3-oxoalkyldithiocarbamic acids from 1,3-isothiocyanato ketones

Sodium salts of 3-oxoalkyldithiocarbamic acids were obtained by the reaction of 1,3-isothiocyanato ketones with sodum hydrosulfide. These salts were converted by reaction with methyl iodide into the corresponding dithiocarbamates, and with a mineral acid into the 6-hydroxytetrahydro-1,3-thiazine-2-thiones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 416–419, March, 1991.     

Synthesis and derivatization of ethynyl alpha,alpha-dibromomethyl ketones: formation of highly functionalized vinyl triflates

[reaction: see text] We describe the synthesis of alpha,alpha-dibromomethyl ynones (8) and their subsequent derivatization to vinyl acetates (10). These vinyl acetates feature a 1,1-dibromo-olefin moiety, which is readily exploited in palladium-catalyzed Sonogashira, Stille, and Suzuki cross-coupling reactions with alkynes, stannanes, and boronic acids, respectively. A novel one-pot process then directly converts the resulting vinyl acetates 11-13 to the vinyl triflate derivatives 14a-j.     

Synthesis of trisubstituted imidazoles via a convergent reaction network from methyl ketones and benzoins

A novel method for constructing trisubstituted imidazoles has been created using simple and readily available aromatic ketones, benzoins, and ammonium acetate as starting materials. The new synthetic strategy utilized a convergent integration of two self-labor domino sequences, providing a typical example for logical self-organization synthesis.     

Chemistry of oxalyl derivatives of methyl ketones

It was established by IR, UV, and PMR spectroscopy that 2-phenacylidenebenzo-1,4-thiazin-3-ones are formed in the reaction of o-aminothiophenol with aroylpyruvic acids or 5-arylfuran-2,3-diones. 2-Carbomethoxy-2-phenacyl-1,3-benzothiazolines were isolated in the reaction of o-aminothiophenol with aroylpyruvic acid esters.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 755–757, June, 1977.     

Determination of methyl ketones by pH measurement

A rapid and accurate method for the determination of methyl ketones in presence of ethyl alcohol is described; it depends upon the measurement of pH after the liberation of free hydrochloric acid in the hydroxylamine hydrochloride reaction

     

Preparation of functionalized ketones via low temperature grignard reaction

δ-Chloroketones and 5-oxo-9-decenoic acid methyl ester were prepared from 5-chlorovaleryl chloride and methyl 4-(chloroformyl)-butyrate via Grignard reaction in tetrahydrofuran at ?70°.     

Pyrazyl methyl ketones as potential chelating agents

Summary A series of 2-pyrazylmethyl ketones was prepared by the acylation of 2-pyrazylmethylsodium with the esters of various carboxylic acids. The methyl, ethyl,iso-propyl,tent-butyl, and phenyl ketones were prepared.The analytical utility of the 2-pyrazylmethyl ketones was systematically investigated and potentially useful interactions with a number of divalent metal ions were observed.

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Zusammenfassung Eine Reihe von 2-Pyrazylmethylketonen wurde durch Acylierung von 2-Pyrazylmethylnatrium mit Estern verschiedener Carbonsäuren hergestellt; und zwar das Methyl-, Äthyl-, Isopropyl-, tert-Butyl- und das Phenylketon. Die analytische Brauchbarkeit dieser Verbindungen wurde systematisch untersucht und eine Anzahl zweiwertiger Metalle gefunden, die mit diesen Ketonen in geeigneter Weise reagieren.

     

Direct formation of functionalized ketones via the coupling of functionalized organocopper reagents with acid chlorides

Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of a copper(I) iodide/triphenyl-phosphine complex. These copper solutions react rapidly with functionalized alkyl halides to give organocopper reagents which have been effectively trapped with acid chlorides giving functionalized ketones in good yields. Ester, nitrile, chloride, remote epoxide, and, to some degree, ketone groups can be tolerated by this approach.     

Synthesis of rhenium chelated MAG3 functionalized rosette nanotubes

Rosette nanotubes (RNTs) are discrete nanostructures self-assembled from a guanine–cytosine hybrid motif (G∧C) under aqueous conditions. These materials have substantial design flexibility and a range of applications, which are partly attributed to their diverse surface functionalization. Given the potential for interesting properties resulting from a metal-RNT construct, here we describe an oxorhenium-functionalized RNT. More specifically, we present the synthesis of a twin G∧C motif expressing the mercaptoacetyl triglycine (MAG₃) ligand. We then examine the chelation reaction of the MAG₃ with ReOCl₃(PPh₃)₂ and self-assemble the resulting ReO-MAG₃-G∧C conjugate into RNTs under DMSO and aqueous conditions.