Alkyl Carbonyl Research Articles

English

The present study assessed the antifungal properties of extracts of Coriolopsis polyzona against fungi isolated from remnant foods and wastewater that are discharged into the environment without treatment. Species of fungi isolated from remnant foods and wastewater in Akure metropolis are Aspergillus fumigatus, Aspergillus niger, Mucor mucedo, Penicillium chrysogenum, Apsergillus flavus, Fusarium oxysporum, Penicillium italicium, Triscelophorus monosporus and Rhizopous stolonifer. Phytochemical constituents in the extracts of C. polyzona ranged from 0.75 to 14.20 mg/g for saponins, flavonoids, alkaloids, tannins and steroids. The percentage inhibition of fungal mycelia by C. polyzona extracts against isolated fungi at concentration of 50 to150 mg/ml ranged from 2.7 to 37.7%. Purified extracts exhibited better mycelia inhibition of 42.2% on Penicillium chrysogenum and 34.1% on Aspergillus fumigatus that were resistance to fluconazole and ketoconazole respectively. The presence of phytochemicals and functional groups such as hydroxyl (OH), alkyl (C-H) carbonyl (C=O) and aromatic ring (C=C) in the extracts of C. polyzona may be responsible for the antifungal effect of the extracts. Compounds associated with these functional groups if isolated and purified may help in combating the present phenomenon of resistance of fungi to commercial antifungal agents. Key words: Restaurant wastes, Coriolopsis polyzona, mycelia inhibition, functional groups, environment.

Synthesis of intermediate compounds with P-N bond from (thio)carbamates and chlorodioxaphospholanes and -phosphorinanes and their reactivity

A variety of 2-( N -alkoxy(thio)carbonyl alkyl(aryl)amino)-1,3,2-dioxaphospholanes and phosphorinanes were prepared from chlorodioxaphospholanes and phosphorinanes. Their structures were determined by IR, Mass and NMR spectroscopy. These compounds were employed in direct reactions with elemental sulphur and methylester of chloroacetic acid giving potentially physiologically active N -phosphorylated carbamates with P(O)-N and P(S)N bonds.

Synthesis and Herbicidal Activity of 2‐Alkyl(aryl)‐4‐amino‐3‐[alkyl(alkoxy)carbonyl]‐5‐cyano‐6‐[(3‐trifluoromethyl)phenoxy]‐pyridines

To find novel bleaching herbicide lead compounds, a series of novel 2‐alkyl(aryl)‐4‐amino‐3‐[alkyl(alkoxy)carbonyl]‐5‐cyano‐6‐[(3‐trifluoromethyl)phenoxy]‐pyridines was designed and synthesized by the multistep reactions. N,S‐acetal 1 reacted with 2 to obtain multisubstituted pyridines 3 in the presence of zinc nitrate as the catalyst. The target compounds 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l were formed by the oxidation of 3, followed by the substitution with 3‐(trifluoromethyl)phenol in the presence of potassium carbonate. Their structures were confirmed by IR, 1H NMR, EI‐MS, and elemental analyses. The preliminary bioassays indicated that some of them displayed moderate herbicidal activity against dicotyledonous weed Brassica campestris L at the concentration of 100 mg/L.

Pyridinyl- and Furanyl-methylzinc Chloride: Direct Preparation and Coupling Reactions

Benzylic organometal reagents are highly relevant for the synthesis of organic complex molecules, especially for the homologation of organometallics. By utilizing these benzylmetallic reagents, the introduction of a diarylmethanemoiety presented in many natural compounds and biologically active materials has been successfully accomplished. To perform this strategy, a wide range of benzylic metal reagents have been used. Along with the presence of a simple benzylic moiety in many natural materials, a nonfunctionalized or functionalized heterobenzylic moiety is also found and considered as an important class in biologically active pharmaceutical products. For the synthesis of these active compounds, heterobenzylic halides were used mostly as a coupling partner of the corresponding organometallic reagents in the Stille, Suzuki and Negishi couplings. However, some of the heterobenzylic halides are very unstable in the transition metal-catalyzed coupling reactions. To alleviate this difficulty, heterobenzylic sulfonium salts have also been participated in Pd-catalyzed coupling reactions of organometalllics. As described above, each heterobenzylic compound was used as a very efficient coupling partner in the cross-coupling reactions. In addition to this approach for the preparation of compounds containing a heterobenzylic moiety, utilizing the corresponding heterobenzylic organometal reagents would be another way to synthesize various different types of heterobenzyl-moiety-containing derivatives. Nevertheless, to the best of our knowledge, there is no report on the direct preparation of the heterobenzylic organometal reagent and its application in organic synthesis. In our continuing effort to explore the utility of organozinc reagents, it was found that several heterobenzylzinc reagents were easily prepared and their subsequent cross-coupling reactions were also carried out under mild conditions with some limitations. We herein report our first results of utilizing heterobenzylic zinc reagents. For the preparation of heterobenzylzinc halides, readily available heterobenzyl halides such as 2-chloro-5-(chloromethyl)pyridine, 2-chloromethylpyridine, and 2-ethoxycarbonyl5-(chloromethyl)furan were chosen. The oxidative addition of active zinc was generally carried out in THF at room temperature. First attempt for the preparation of heterobenzylzinc was executed with 2-chloro-5-(chloromethyl)pyridine. In the presence of 2.0 equivalent of active zinc, the oxidative addition into the C-Cl bond of the benzylic position was completed in 4.0 h at room temperature to afford the corresponding organozinc reagent, (6-chloropyridin-3-yl)methylzinc chloride (A) without forming of any homocoupling product (Scheme 1). To investigate the applicability of the resulting organozinc reagent, we first examined the palladium-catalyzed crosscoupling reaction with a variety of acid chlorides. The results are summarized in Table 1. The reaction of A with benzoyl chloride was carried out in the presence of 1 mol % of Pd(PPh3)2Cl2 at room temperature within 30 min providing the ketone 1a in 65% isolated yield (entry 1, Table 1). During the coupling reaction, no detectable amount of homocoupling product of organozinc was observed. In addition, as we have developed a new catalytic system for the cross-coupling reaction of organozincs with acid chlorides, coupling reaction has also been tried with 2 mol % of Ni(acac)2-catalyst. Similar results were obtained in terms of yield and purity. Therefore, the rest of the reactions in this study were conducted using a Pd(II)-catalyst system. Not only bromobenzoyl chlorides (entries 2 and 3, Table 1) but chlorobenzoyl chloride (entry 4, Table 1) was successfully coupled with A under the Pd-catalyst system resulting in the formation of the ketones (1b, 1c, and 1d, Table 1) in moderate yields. Even higher yields were obtained from using benzoyl chlorides containing an electron-donating group. As depicted in Table 1, both 4-methyland 4-methoxybenzoyl chlorides reacted with A leading to ketones (1f and 1g, Table 1) in 76% and 82% isolated yields, respectively. The reaction of A with 4-chloromethylbenzoyl chloride gave the expected product 1h in 54% yield leaving benzyl chloride intact (entry 7, Table 1). By using heteroaromatic acid chlorides such as 2-furancarbonyl chloride and 2-thiophenecarbonyl chloride, the cross-coupling products (1i and 1j, Table 1) were obtained in moderate yield (entries 8 and 9). The alkyl carbonyl chlorides (entries 10 and 11) were also suitable for the Pd-catalyzed coupling reaction, furnishing the

Combining Zn Ion Catalysis with Homogeneous Gold Catalysis: An Efficient Annulation Approach to N-Protected Indoles.

The Fischer indole synthesis is perhaps the most powerful method for indole preparation, but it often suffers from low regioselectivities with unsymmetric aliphatic ketone substrates and strong acidic conditions and is not suitable for α,β-unsaturated ketones. In this article, we disclose an efficient synthesis of N-protected indoles from N-arylhydroxamic acids/N-aryl-N-hydroxycarbamates and a variety of alkynes via a cooperative gold and zinc catalysis. The zinc catalysis is similar to the related zinc ion catalysis in metalloenzymes such as human carbonic anhydrase II and substantially enhances the O-nucleophilicity of N-acylated hydroxamines by forming the corresponding Zn chelates. The Zn chelates can attack gold-activated alkynes to form O-alkenyl-N-arylhydroxamates, which can undergo facile 3,3-sigmatropic rearrangements and subsequent cyclodehydrations to yield N-protected indole products. This new chemistry offers several important improvements over the Fischer indole synthesis: a) the reaction conditions are mildly acidic and can tolerate sensitive groups such as Boc; b) broader substrate scopes including substrates with pendant carbonyl groups (reactive in the Fischer chemistry) and alkyl chlorides (e.g., 3f); c) better regioselectivities for the formation of 2-substituted indoles under much milder conditions; d) 2-alkenylindoles can be prepared readily in good to excellent yields, but the Fischer chemistry could not; e) with internal alkynes both steric and electronic controls are available for achieving good regioselectivities, while the Fischer chemistry is in general problematic.

Unexpected observation of carbonyl oxide radical cations from peroxy radical cations. A new isomerism of oxygen‐containing radical cations

DFT computational studies with B3LYP/6‐31G(d) level theory has been carried out for peroxy radical cations which are formed by the reaction of molecular oxygen with aliphatic and aromatic olefin radical cations. The calculations have led us to find rearrangement reactions of the peroxy radical cations to the isomeric carbonyl oxide radical cations. The results show that the peroxy radical cations in which their positive charges at the olefinic carbons cannot be stabilized due to the structural requirements have a great tendency to undergo the rearrangement. Thus, 2‐methylpropene radical cation does not afford a peroxy radical cation formed by the addition of molecular oxygen at 2‐position of the olefinic carbon, and DFT calculations to locate the structure were found to give a rearranged ethyl methyl carbonyl oxide radical cation, which is significantly more stable than the peroxy radical cation. It was also found that carbonyl oxide radical cations, depending on the structures, are as stable as, or even more stable than, the isomeric peroxy radical cations which are formed by the addition of molecular oxygen to the aromatic olefin radical cations derived from trans‐stilbene and β‐methylstyrene. The results also indicate that the C–O bonds are shorter than the O–O bonds in the alkyl carbonyl oxide radical cations examined, which suggests that oxygen lone pair delocalization to the carbonyl carbon play an important role for the determinaton of the structures and their stability. Copyright © 2012 John Wiley & Sons, Ltd.

LANTHANUM TITANATE NANOPARTICLES ER FLUIDS WITH HIGH PERFORMANCE

A new type of electrorheological (ER) fluid consisting of lanthanum titanate (LTO) nanoparticles is developed. The ER fluids were prepared by suspending LTO powder in silicone oil and the particles were fabricated by wet chemical method. This ER fluid shows excellent ER properties: The static yield stress reaches over 150 kPa under 5 kV/mm with linear dependence on the applied DC electric field, and the current density is below 10 μA/cm2. In order to investigate the affect factor on the ER behavior, the LTO powder were heated under different temperatures. The ER performances of two particles treated under different temperatures were compared and the composition changes for those particles were analyzed with TG-FTIR technique. It was found that the static yield stress of the suspensions fell from over 150 kPa to about 40 kPa and the current densities decreased prominently as the rise of the heating temperature. TG-FTIR analysis indicated that polar groups remained in the particles such as alkyl group, hydroxyl group and carbonyl group etc., contribute to the ER effect significantly. The experimental results are helpful to understand the mechanism of the high ER effect and to synthesize better ER materials.

An efficient synthesis of dithiocarbamates under ultrasound irradiation in water

Multicomponent reactions with ultrasonic activation have been used as a simple, rapid, atom economic, and green method for the synthesis of dithiocarbamate derivatives in water. The one-pot, three-component condensation of primary and secondary amines with carbon disulfide and unsaturated carbonyl compounds or alkyl halides under ultrasonic irradiation was developed as a green and fast protocol for the rapid high-yielding preparation of dithiocarbamates in water.

A novel l-amino acid ionic liquid for quick and highly efficient synthesis of oxime derivatives – An environmental benign approach

A mild, efficient, and eco-friendly procedure for the conversion of aliphatic, alicyclic and aromatic carbonyl compounds into the corresponding oximes, was catalyzed by a novel imidazolium based ionic liquid coupled with amino acid (asparagine) (l-AAIL, l-Amino acid functionalized ionic liquid) catalytic system. The quantitative conversion of aryl and alkyl carbonyl compounds into the corresponding oximes was achieved by simply grinding at ambient temperature using 0.05mmol of catalyst in 50s. In addition, this L-AAIL catalyst exhibited good reusability for five consecutive trials without significant loss of its catalytic activity.

Characterization of Tribofilm from Sulfurized Mohwa Oil

The reaction products of sulfurized Mohwa oil with iron powder in hydrocarbon medium at 150°C for 8 h were studied to investigate the type of lubricant films formed during their application as antiwear and extreme pressure additives. The main reaction product was isolated on the basis of its solubility in mixed solvent. Surface characterization was carried out using ultraviolet-visible spectroscopy (UV), fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), and high frequency reciprocal rig (HFRR). An examination of their elemental analysis and instrumental analysis data reveals that there is reduction in the length of the alkyl chains and carbonyl ester groups with formation of inorganic iron sulfides. Polymerized product with a number of ketonic and aldehydic groups containing iron and sulfur in the polymeric films in the form of unsaturated cyclic rings was also formed. The films are organo-inorganic in nature, unlike the purely inorganic iron sulfide type. The load-carrying characteristic of this product is strongly influenced by the type of the film formed on the iron surfaces.

ChemInform Abstract: Radical-Mediated Vicinal Dialkylation of α,β-Unsaturated Carbonyl Compounds.

Abstract The three-component coupling reaction have been achieved by irradiation of a mixture of α, β-unsaturated carbonyl compounds, alkyl halides, and allylplumbanes in high yields.

ChemInform Abstract: General Synthesis of Cyclopropenones and Their Acetals.

Abstract Metalated cyclopropenone acetals 5 react with a variety of electrophiles, including alkyl halides, carbonyl compounds, vinyl iodides, vinyl triflates, and aryl iodides, to give substituted cyclopropenone acetals in high yield. Hydrolysis of the acetal under acidic conditions gives the corresponding cyclopropenone. The reaction sequence has realized an efficient synthesis of an antibiotic penitricin ( 1 ).

ChemInform Abstract: Reactions of Oxathio-Substituted Crotyl Lithium with Alkyl Halides and Carbonyl Compounds. An Example of an Ambident Nucleophile.

ChemInform Abstract: Reactions of Oxathio-Substituted Crotyl Lithium with Alkyl Halides and Carbonyl Compounds. An Example of an Ambident Nucleophile.

Enantioselective Aza‐Morita–Baylis–Hillman Reaction Using Aliphatic α‐Amidosulfones as Imine Surrogates

AbstractThe bifunctional catalyst 6′‐deoxy‐6′‐acylamino‐β‐isocupreidine (1) served both as a base to trigger the in situ generation of N‐sulfonylimine from readily available α‐amidosulfones and as a chiral nucleophile to initiate the enantioselective aza‐Morita–Baylis–Hillman (aza‐MBH) reaction. α‐Methylene‐β‐amino‐β‐alkyl carbonyl compounds, difficultly accessible previously, can now be synthesized in excellent yields and enantioselectivities.

Synthesis and Bioactivity of Some New 2‐(Alkoxy carbonyl alkyl)‐6‐bromo‐3,4‐dihydro‐3‐(α‐methyl benzyl)‐2‐oxo‐benzo[e] [2H‐1,3,2‐oxazaphosphinine] Derivatives

AbstractSynthesis of some new 2‐(alkoxy carbonyl alkyl)‐6‐bromo‐3,4‐dihydro‐3‐(α‐methyl benzyl)‐2‐oxo‐3‐benzo‐ [e][2H‐1,3,2‐oxazaphosphinine] derivatives was accomplished through a two step process, which involves the condensation of 2‐[(α‐methylbenzyl amino)methyl]‐4‐bromophenol (1) with phosphorus oxychloride in equimolar quantities in the presence of triethylamine in dry toluene in 50–55 °C producing the corresponding intermediate (2), and subsequent reaction with the amino acid alkyl ester in dry tetrahydrofuran in the presence of triethylamine at different temperatures. They exhibited significant antibacterial and fungal activity.

Synthesis and Reactivity of Functionalized Arylcopper Compounds by Transmetalation of Organosilanes

Reactive organometallics are part and parcel of synthetic chemistry. Organosilanes potentially represent a cheap, robust, and environmentally benign precursor to reactive organometallics, but the nature of the very stable C−Si bond has generally prevented their use as precursors to more reactive organometallics. We present investigations into a copper fluoride complex which activates organosilanes in anhydrous media under mild conditions, effecting transmetalation to produce stable and isolable organocopper species containing sensitive functional groups including carbonyl groups, aryl bromides, benzylic chlorides, and alkyl ketones. This discovery allows us to better understand the fundamental reactivity of presumed intermediates in copper-catalyzed reactions and to develop new catalytic bond-forming processes of organosilane reagents.

Oxidative-substitution reactions of electron-rich aromatic compounds with BF 3-activated iodonium ylides

The treatment of electron-rich aromatic substrates with phenyliodonium bis(carbonyl)methylides in the presence of Et 2O·BF 3 leads to bis(carbonyl)alkylation of the aromatic nucleus.

金属スルホナート触媒による不飽和炭化水素および複素芳香族化合物の活性化を利用した炭素‐炭素結合形成反応に関する研究

Lewis acids have been used as a mediator or a catalyst so far mainly for activation of heteroatom-containing compounds like carbonyl compounds, imines and alkyl halides. In contrast, we have been focusing on developing new carbon-carbon bond forming reactions utilizing activation of hydrocarbons by a metal sulfonate catalyst. In this context, we found that arenes as well as heterocyclic arenes add to alkynes in the presence of indium triflate [In (OTf)3, Tf=SO2CF3] as a catalyst. These findings are followed by development of facile synthesis of aryl-and heteroarylannulated [a] carbazoles by the reaction of propargyl ethers with 2-aryl-and 2-heteroarylindoles. In addition to the above reactions, metal triflates catalyzed dimerization of vinylarenes with the aid of a palladium catalyst (activation of C = C), nucleophilic substitution using a pyrrolyl group as a carbon leaving group (activation of C-C) and oxidative coupling between lactams and heterocyclic arenes (activation of C-H).

Preparation of PEG-grafted silica particles using emulsion method

Low-molecular-weight poly(ethylene glycol) (PEG) was grafted onto the surface of silica particles by a two-step addition process. To prepare PEG-grafted silica particles, PEGME–IPTES monomers were synthesized by the reaction of 3-(triethoxysilyl)propyl isocyanate (IPTES) with poly(ethylene glycol) methyl ether (PEGME) in the presence of dibutyltin dilaurate. To remove PEGME residues, excessive IPTES was added to the solution. The peak for a urethane carbonyl group of PEGME–IPTES was observed at 1722 cm −1 by FT-IR spectroscopy. Through the sequential addition of TEOS and PEGME–IPTES monomers, PEG was introduced onto the surface of silica particles. The introduction of PEG onto the surface was observed by SEM, Brunauer–Emmett–Teller (BET), and FT-IR spectroscopy. When PEG was grafted onto the surface of silica particles, the surface area of silica particles decreased and the average pore diameter increased. The peak for urethane carbonyl group and alkyl group of PEG appeared at 1722 cm −1 and 2920 cm −1.

1,3-Dimethyl-2-phenylbenzimidazoline (DMPBI)-Acetic Acid: An Effective Reagent System for Photoinduced Reductive Transformation of α,β-Epoxy Ketones to β-Hydroxy Ketones

A combination of 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI) and acetic acid has been utilized for photoinduced reductive transformation of α,β-epoxy ketones to β-hydroxy ketones. Study on photoreactions using several proton donors revealed that acetic acid is superior to other proton donors such as HCl, p-TsOH, MeOH, and water. 1,3-Dimethyl-2-phenylbenzimidazolium was produced in the reaction with acetic acid while N-benzoyl-N,N′-dimethyl-o-phenylenediamine was formed in aqueous solvents. When THF solutions containing aryl carbonyl possessing α,β-epoxy ketones and DMPBI and acetic acid were irradiated (λ > 280 nm), β-hydroxy ketones were isolated in good to excellent yields. Photosensitized conditions (λ > 340 nm) were employed for the reactions of alkyl carbonyl possessing α,β-epoxy ketones.