Alkyl Phenyl Research Articles

A Facile Method for Synthesis of Alkyl Phenyl Selenides. The Reaction of Diphenyl Diselenide with Oxygen-containing Compounds Using La/Me3SiCl/cat.I2/cat.CuI System

Abstract Alcohols, ethers, and esters were directly converted to the corresponding alkyl phenyl selenides by the reaction of diphenyl diselenide and the La/Me3SiCl/cat.I2/cat.CuI. It was suggested that alkyl phenyl selenides were formed by the SH2 type reaction of diphenyl diselenide with alkyl radicals generated from alcohols, ethers or esters.

Kinetics and mechanism of (salen)MnIII‐catalysed oxidation of organic sulfides with sodium hypochlorite

AbstractThe oxidation of organic sulfides with several substituted oxo(salen)manganese(V) complexes was investigated in 90% acetonitrile–10% water and the reaction is second‐order overall, first‐order each in sulfide and complex. Electron‐releasing substituents in sulfides and electron‐withdrawing substituents in oxo(salen)manganese(V) complexes accelerate the rate of oxidation. The second‐order rate constants for the oxidation of p‐substituted phenyl methyl sulfides follow a linear Hammett relationship with ρ = −1.85. However, correlation between log k2 and 2σ is excellent with ρ = 0.48 for the oxidation of thioanisole by substituted oxomanganese(V) complexes. The rate of oxidation of alkyl phenyl sulfides and dialkyl sulfides with oxo complexes was also examined and the reactions show a moderate steric effect. Substituent, acid and solvent effect studies reveal the operation of an SN2 mechanism. Copyright © 2003 John Wiley & Sons, Ltd.

Efficient Method for the Preparation of Carboxylic Acid Alkyl Esters or Alkyl Phenyl Ethers by a New-Type of Oxidation–Reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone and Alkoxydiphenylphosphines

Abstract A new-type of oxidation–reduction condensation proceeded smoothly to afford carboxylic acid alkyl esters or alkyl phenyl ethers in good to high yields by combined use of alkoxydiphenylphosphines (1) having primary, bulky secondary or tertiary alkoxy groups, a mild quinone-type oxidant such as 2,6-dimethyl-1,4-benzoquinone (DMBQ) and carboxylic acids or phenols. Generally, alkoxydiphenylphosphines were prepared easily from chlorodiphenylphosphine (2) and alcohols in the presence of pyridine, and were isolated by distillation. On the other hand, the phosphines 1 were also prepared in situ from N,N-dimethylaminodiphenylphosphine (3a) and primary or secondary alcohols while primary, bulky secondary or tertiary alkoxydiphenylphosphines were alternatively formed in situ by adding 2 to the nBuLi-treated alcohols in order to perform the above reactions by a one-pot procedure from alcohols and nucleophiles. The reaction of thus formed 1, DMBQ and carboxylic acids or phenols afforded the corresponding alkylated products, including hindered secondary and tertiary alkylated ones, in good to high yields at room temperature. In the case of using chiral secondary alcohols, the corresponding carboxylic acid alkyl esters were obtained as well in high yields with perfect inversion of stereochemistry by SN2 replacement.

Reductive lithiation of alkyl phenyl sulfides in diethyl ether. A ready access to α,α-dialkylbenzyllithiums

Diethyl ether is a convenient solvent for the conversion of benzylic phenyl sulfides to the corresponding organolithiums by an uncatalyzed reductive metalation, while catalysis by naphthalene is required to achieve the same reaction for alkyl phenyl sulfides. The addition of magnesium 2-ethoxyethoxide to solutions of unstable alkyllithiums prepared in this way provides storable reagents.

High-Intensity Ultrasound-Promoted Reformatsky Reactions.

For Abstract see ChemInform Abstract in Full Text.

Alkylation of Phenols by Oxidation‐Reduction Condensation Using 2,6‐Dimethyl‐1,4‐benzoquinone and Alkoxydiphenylphosphine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Unexpected Differences in the α‐Halogenation and Related Reactivity of Sulfones with Perhaloalkanes in KOH‐t‐BuOH.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Conversion of Pollutants in Dilute Aqueous Waste Streams to Useful Products: a Potential Method Based on Phase-Transfer Catalysis

Many waste streams contain anions at low concentration in water. This paper describes results obtained when aqueous solutions of various anions at 1 wt % were subjected to reactions with alkyl and acyl halides without solvent. High yields of valuable products such as phenylacetonitrile, alkyl phenyl ethers, alkyl acrylate, and benzoyl cyanide were obtained at moderate temperatures and reaction times. The formation of byproducts deriving from reactions with large amounts of water was easily controlled. The method was successfully applied to selectively react and extract a target anion out of a mixture of anions.

One‐Pot Synthetic Method of Unsymmetrical Diorganyl Selenides: Reaction of Diphenyl Diselenide with Alkyl Halides in the Presence of Lanthanum Metal.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and Anti-histaminic Evaluation of N-Phenyl-(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines

New N- phenyl(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines, 5a–e, have been synthesized from the corresponding 3-phenyl(alkyl)carbamoyl-2-iminooxazolidines 2. A two-stage hydrolysis reaction led finally to the corresponding ring-opened N-phenyl(alkyl)-N′-[1-{3-(dialkylamino)-propan-2-ol}]ureas 4. The oxazoline ring was regenerated through an intramolecular nucleophilic substitution involving an halogen atom introduced by the reaction of thionyl chloride on 4. Pharmacological properties of 5a–e were evaluated on histaminic and adrenergic receptors in guinea-pig trachea and rat aorta. Compounds 5b and 5e showed a selective anti-histaminic effect on guinea-pig airways, but a significant response was obtained for a concentration >10-6 M. No pharmacological activity was obtained with oxazoline 5c whereas oxazolines 5a and 5d seemed to present a non-selective effect on the contractile mechanism of the smooth muscle cell.

Selective Synthesis of Carbamate‐Protected Polyamines Using Alkyl Phenyl Carbonates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Tin‐Free Radical Cyanation of Alkyl Iodides and Alkyl Phenyl Tellurides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cloning, expression and tissue distribution of a tetrameric form of pig carbonyl reductase

In this study, we isolated a cDNA for tetrameric carbonyl reductase (CR) from pig heart. The pig CR showed high amino acid sequence identity (81%) with rabbit NADP +-dependent retinol dehydrogenase (NDRD). The purified recombinant pig CR and NDRD were about 100-kDa homotetramers and exhibited high reductase activity towards alkyl phenyl ketones, α-dicarbonyl compounds and all- trans-retinal. The identity of NDRD with the tetrameric CR was verified by protein sequencing of CR purified from rabbit heart. Both tetrameric CR and its mRNA were ubiquitously expressed in pig and rabbit tissues. The pig and rabbit enzymes belonged to the short-chain dehydrogenase/reductase family, and their sequences comprise a C-terminal SRL tripeptide, which is a variant of the type 1 peroxisomal targeting signal, SKL. Transfection of HeLa cells with vectors expressing pig CR demonstrated that the enzyme is localized in the peroxisomes. Thus, the tetrameric form of CR represents the first mammalian peroxisomal enzyme that reduces all- trans-retinal as the endogenous substrate.

Comparative studies of the physical and hydrophobic properties of TEOS based silica aerogels using different co-precursors

In the present paper, the experimental results on the physical and hydrophobic properties of tetraethoxysilane (TEOS) based silica aerogels using six different organosilane co-precursors (C.P) of the type RnSiX4-n as synthesis components, are reported and discussed. The aerogels have been produced by sol-gel processing followed by supercritical drying using methanol solvent extraction. The molar ratio of TEOS, ethanol (EtOH), water (0.001M oxalic acid (H2C2O4) catalyst) was kept constant at 1:5:7, respectively, and the molar ratio of C.P/TEOS (A) was varied from 0.1 to 0.6 and compared the aerogel properties. The hydrophobicity of the aerogels has been tested by the contact angle measurements. The contact angle (θ) has been found to be the highest (θ =136˚) for the trimethylethoxysilane (TMES) co-precursor, while for the other co-precursors it is in between 12˚8 and 13˚8. The surface chemical modification of the hydrophobic aerogels has been studied using Fourier Transform Infrared Spectroscopy (FTIR). As the C.P/TEOS molar ratio increased, the intensity of the C–H and Si–C peaks in the FTIR spectra increased, clearly indicating the organic modification of the aerogels. The aerogels based on mono-alkyl (CH3) trialkoxysilane co-precursor have shown higher optical transmission (≈65%) compared to the phenyl, di or tri alkyl alkoxysilanes (5–50%). The trialkyl modified aerogels showed the lowest bulk density (118.3 kg/m3) and volume shrinkage (<2%). The alkyl alkoxy/chloro–silane modified aerogels have been found to be thermally stable up to a maximum temperature of 573 K, whereas the phenyl trialkoxysilane modified aerogels are stable up to a temperature as high as 823 K. The aerogels have been characterized by scanning electron microscopy, thermogravimetric and differential thermal analyses.

Investigation of the configuration of alkyl phenyl ketone phenylhydrazones from ab initio 1H NMR chemical shiftsElectronic supplementary information (ESI) available: Full geometry optimization at the B3LYP/6-31G(d) level of approximation. See http://www.rsc.org/suppdata/ob/b3/b307528a/

Using ab initio GIAO calculations the experimental 1H NMR spectra of the E and Z isomers of alkyl phenyl ketone phenylhydrazones R1-C(Ph) = N-NH-Ph (R1 = Me, Et, iPr, and tBu) have been re-interpreted and deviations from Karabatsos' rule or from the assignment of Bellamy and Hunter have been discussed in the light of the optimized geometrical structures.

Tandem Enzyme‐Catalyzed Oxidations of Alkyl Phenyl Sulfides and Alkyl Benzenes: Enantiocomplementary Routes to Chiral Phenols.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Alkylation of Phenols by Oxidation-Reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone and Alkoxydiphenylphosphine

Abstract Various alkyl phenyl ethers were obtained in high yields by way of oxidation-reduction condensation where alkoxydiphenylphosphine, prepared easily from chlorodiphenylphosphine and corresponding alcohols, was treated with various phenols in the co-existence of 2,6-dimethyl-1,4-benzoquinone(DMBQ) under mild conditions.

Mechanism of the oxidation of aromatic sulfides catalysed by a water soluble iron porphyrin.

The oxygen atom transfer-electron transfer (ET) mechanistic dichotomy has been investigated in the oxidation of a number of aryl sulfides by H2O2 in acidic (pH 3) aqueous medium catalysed by the water soluble iron(III) porphyrin 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p',p",p"'-tetrasulfonic acid iron(III) chloride (FeTPPSCl). Under these reaction conditions, the iron-oxo complex porphyrin radical cation, P+. Fe(IV)=O, should be the active oxidant. When the oxidation of a series of para-X substituted phenyl alkyl sulfides (X = OCH3, CH3, H, Br, CN) was studied the corresponding sulfoxides were the only observed product and the reaction yields as well as the reactivity were little influenced by the nature of X as well as by the bulkiness of the alkyl group. Labelling experiments using H(2)18O or H(2)18O2 clearly indicated that the oxygen atom in the sulfoxides comes exclusively from the oxidant. Moreover, no fragmentation products were observed in the oxidation of a benzyl phenyl sulfide whose radical cation is expected to undergo cleavage of the beta C-H and C-S bonds. These results would seem to suggest a direct oxygen atom transfer from the iron-oxo complex to the sulfide. However, competitive experiments between thioanisole (E degree = 1.49 V vs. NHE in H2O) and N,N-dimethylaniline (E degree = 0.97 V vs. NHE in H2O) resulted in exclusive N-demethylation, whereas the oxidation of N-methylphenothiazine (10, E degree = 0.95 V vs. NHE in CH3CN) and N,N-dimethyl-4-methylthioaniline (11, E degree = 0.65 V vs. NHE in H2O) produced the corresponding sulfoxide with complete oxygen incorporation from the oxidant. Since an ET mechanism must certainly hold in the reactions of 10 and 11, the oxygen incorporation experiments indicate that the intermediate radical cation, once formed, has to react with PFe(IV)=O (the reduced form of the iron-oxo complex which is formed by the ET step) in a fast oxygen rebound. Thus, an ET step followed by a fast oxygen rebound is also suggested for the other sulfides investigated in this work.

Unexpected differences in the alpha-halogenation and related reactivity of sulfones with perhaloalkanes in KOH-t-BuOH.

Most alkyl phenyl sulfones are readily alpha-chlorinated with CCl(4) and alpha-brominated with CBrCl3 in KOH-t-BuOH via radical-anion radical pair (RARP) reactions. While isopropyl mesityl sulfone (4) is easily alpha-chlorinated with CCl(4), it was completely recovered when treated with the more reactive CBrCl3. Subsequent investigations showed the latter result to be due to the poor acidity of 4 together with the rapid depletion of CBrCl3 and KOH by their reaction with each other, and led to a variety of other important results. 4-Hydroxyphenyl isopropyl sulfone (6) is unreactive with either CCl4 or CBrCl3 in KOH-t-BuOH, its phenoxide anion strongly reducing the electronegativity of the sulfonyl group, thereby inhibiting alpha-anion formation. This effect is reversed by the electron-withdrawing influence of two alpha-phenyls, so that benzhydryl 4-hydroxyphenyl sulfone (8) is readily alpha-halogenated in KOH-t-BuOH with CCl4 or CBrCl3. On further contact with KOH-t-BuOH the alpha-halogenated sulfones from 8 are decomposed into benzophenone and phenol. While the alpha-halogenated derivatives of 4-methoxyphenyl benzhydryl sulfone (9) are stable to base, they are decomposed even under mildly acidic conditions into 4-methoxyphenyl 4-methoxybenzenethiolsulfonate (9c), phenol, and benzophenone. Mono-alpha-halogenation of benzyl phenyl sulfone (10) enhances the rate of the subsequent halogenation, so that alpha,alpha-dihalogenation is attained while much substrate is still present and the mono-alpha-halogenated product is not detected. The ease of reductive debromination of alpha-bromo sulfones with Cl3C- was correlated with the stability of the formed alpha-anions, explaining the success with alpha-bromobenzylic sulfones but failure with alpha-bromoalkyl sulfones. In the presence of air and the absence of competing halogenation, formation of the alpha-anions of alkyl aryl sulfones is quickly accompanied by oxidative cleavage by atmospheric O2, leading to the formation of arenesulfonyl alcohols, arenesulfonyl halides, and haloarenes.

High-intensity ultrasound-promoted reformatsky reactions.

Reformatsky reactions of a phenyl ketone, an alpha-bromoester, zinc dust, and a catalytic amount of iodine in dioxane under high-intensity ultrasound (HIU) irradiation from an ultrasonic probe give high yields of beta-hydroxyesters in short reaction times. A series of alkyl phenyl ketones with increasing steric demands of the alkyl group are evaluated as potential electrophiles for the reactions with several alpha-bromoesters, also having increasing steric demands. The Reformatsky reaction under HIU is found to be concentration dependent.