Mild and Efficient One-Pot Synthesis of 3,5-Disubstituted 1,2,4-Oxadiazoles from Nitriles Mediated by K3PO4

Potassium phosphate, K₃PO₄, has been proved to be a cheap, strong, and efficient reagent for the one-pot synthesis of 3,5-disubstituted-1,2,4-oxadiazoles from nitriles and acid chlorides under mild conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Pd-Catalyzed Reduction of Aldehydes to Alcohols Using Formic Acid as the Hydrogen Donor

Facile and selective reduction of aromatic aldehydes as well as aliphatic aldehydes to alcohols was achieved using formic acid as the hydrogen donor in the presence of a catalytic amount of Pd(OAc)₂ and Cy₃P. It was found that both hydrogen atoms in the formic acid molecule can serve as the hydride source.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Reexamination of the Bromination of 2-Nitrobenzaldehyde with NBS or NaBr-NaIO4 in Sulfuric Acid

Two literature procedures for selective bromination of 2-nitrobenzaldehyde using N-bromosuccinimide (NBS) or NaBr-NaIO₄ in sulfuric acid were examined. In contrast to the reports that 4-bromo-2-nitrobenzaldehyde is formed as a single product in good yield, reactions using NBS gave a number of isomeric mono- and dibrominated products identified by spectroscopical methods and by sodium borohydride reduction to the corresponding benzyl alcohol, and reactions using NaBr-NaIO₄ did not furnish any product.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Asymmetric Synthesis of Novel Vicinal Amino Alcohols via Intramolecular Ketone-N-sulfinylimine Pinacol-Type Reductive Coupling Promoted by SmI2

A novel intramolecular asymmetric ketone-N-sulfinylimine pinacol-type reductive coupling reaction induced by SmI₂ was reported. A series of 1-amino-1,2,3,4-tetrahydronaphthalen-2-carbinols were obtained in moderate to good yields with excellent ee and high dr.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Highly Stereoselective Cyclopropanation of Olefins Catalyzed by a Novel C 3-Symmetric Arsine

A novel C ₃-symmetric arsine was employed in the one-pot cyclopropanation of olefins with carbonyl-stabilized arsonium ylides formed in situ from phenacyl bromide in the presence of NaHCO₃. This new arsine demonstrates good stereoselectivity and activity in the one-pot cyclopropanation of arylidenemalononitrile.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Palladium-Catalyzed Oxidative Carboacetoxylation of Activated Alkynes with Amino Acids

A palladium-catalyzed intramolecular oxidative carboacetoxylation reaction of alkynes with various amino acids has been demonstrated for the first time, forming pharmaceutically important 3-methyleneindolin-2-one. In the presence of Pd(OAc)₂ and ArI(OAc)₂, N-arylpropiolamides underwent tandem acetoxypalladation/C-H functionalization reactions with various Boc-amino acids to form corresponding methyleneindolin-2-ones bearing amino acid motifs in moderate to excellent yields.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

CuFe2O4 Nanoparticles: A Magnetically Recoverable and Reusable Catalyst for the Synthesis of Coumarins via Pechmann Reaction in Water

The synthesis of coumarins by hydroxyalkylation of phenols with ethyl acetoacetate (via Pechmann reaction) is attempted using magnetically separable and reusable CuFe₂O₄ nanoparticles in water.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications ^® for the following free supplemental resource(s): Full experimental and spectral details.]     

A novel self-assembly based on double-layer zinc porphyrin sensitizers in supramolecular solar cell

Two new self-assemblies based on zinc porphyrin dyes ZnPx-ZnPA (x?=?1, 2) were synthesized and used for dye-sensitized solar cells. Capping layer dyes consist of zinc porphyrin (ZnP) as core unit and carbazole (P1), phenothiazine (P2) as electron-donating group. The dye ZnPA contains carboxylic group as an anchor porphyrin with upper dyes (denoted as ZnP1 and ZnP2) formed dyads by coordination bonds of Zn-to-ligand self-assembled devices. The assembly modes were also verified by transmission electron microscopy (TEM). The influence of the upper porphyrins on molecular structure as well as photovoltaic performance was investigated via photophysical and electrochemical studies and calculations. With addition of the phenothiazine unit, the ZnP2-ZnPA possesses better light-harvesting capability with a significantly red-shifted Q-band. The photoelectrochemical efficiencies for ZnP2-ZnPA are better than those of ZnP1-ZnPA ascribed to larger J_sc and V_oc.

     

Green and Reusable Synthetic Procedure for Pyridine N-Oxides Catalyzed by a Lacunary Polyoxometalate

A lacunary Keggin polyoxometalate of K₈[BW₁₁O₃₉H] · 13H₂O was used as an effective and reusable catalyst for pyridine oxidation. Good yields of pyridine N-oxides were obtained in this catalytic system with hydrogen peroxide in water under mild conditions.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Enantioselectivity Investigation of Short Polar Peptides with Different Positions in the Michael Reaction

This work reports the effectiveness of short polar peptides as asymmetric catalysts in Michael reactions to attain good yields of enantio- and diastereoselective isomers. In a comparison, glutamic acid and histidine produced greater ee and yields when they were applied as the second amino acid in short trimeric peptides. These short polar peptides were found to be efficient organocatalysts for the asymmetric Michael addition reaction in water.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Ultrasound-Assisted,One-Pot,Four-Component Synthesis of 1,4,6,8-Tetrahydroquinolines in Aqueous Medium

A series of 2-amino-3-cyano-4-aryl-5-oxo-7,7-dimethyl-1,4,6,8-tetrahydroquinolines were prepared by a one-pot, four-component condensation of aromatic aldehydes, dimedone, malononitrile, and ammonium acetate using K₂CO₃ as a catalyst in aqueous medium under sonic conditions. This protocol, being a single-step reaction, has the advantages of operational simplicity and minimal environmental impact. The synthesized compounds were confirmed through spectral characterization using infrared, ¹H NMR, ¹³C NMR, and CHN analysis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis and Characterization of Some Novel Multisubstituted 6,7-Dihydro-5H-cyclopenta[b]pyridine Derivatives

In this study, we describe systematic preparation of a series of aryl-substituted pyridine derivatives. The 1,5-dicarbonyls (3a–i) were prepared in the solvent-free conditions starting from chalcone derivatives (1a–i). The target compounds, 4-aryl-2-(thiophen-3-yl)-6,7-dihydro-5H-cyclopenta[b]-pyridine derivatives (5a–i), were synthesized by a cyclization reaction of the 1,5-dicarbonyls (3a–i) with ammonium acetate (NH₄OAc) in acetic acid. The characterization of synthesized compounds was proved by elemental analyses, infrared, mass spectrometry, and ¹H and ¹³C NMR spectroscopy.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of Biaryls via Pd-Catalyzed Decarboxylative Coupling of Substituted Benzoic Acids with Phenylboronic Acids

A Pd-catalyzed decarboxylative coupling of substituted benzoic acids with phenylboronic acid has been developed. Under the optimized conditions, a variety of substituted benzoic acids were found to undergo decarboxylative coupling with various phenylboronic acids to give the desired unsymmetrical biaryls in good yields.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of β-Aryl-β-sulfanyl Ketones by a Sequential One-Pot Reaction Using KF/Al2O3 in Glycerol

The title compounds were synthesized by a sequential one-pot reaction of aryl aldehydes, aryl-methyl ketones, and thiols promoted by KF/Al₂O₃. This methodology affords a large number of β-aryl-β-sulfanyl ketone derivatives from aliphatic and aromatic thiols in good yields and is also applicable for solid substrates.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

C-S Bond-Forming Reactions of Barbiturylbromide with Isothiocarbamides in Aqueous Media

The C-S cross coupling of pharmaceutically active barbituric acid derivatives has been achieved by the interaction of selective monobromobarbituric acid with thioureas in an aqueous medium. This method is applicable for simple thiourea as well as monosubstituted thioureas, and corresponding products are obtained in good yield.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Surface Property Characterization of Plasma-Polymerized Tetraf luoroethylene Deposits

Plasma-polymerized tetrafluoroethylene (PPTFE) deposits were characterized by contact angle measurements and critical surface tension γ_Cmeasurements.

The measurements showed surface property changes of the deposits as a function of time and treatments: helium and nitrogen in the feed gas, plasma degradation of the films, and of vacuum/temperature posttreatments. The process was a flow rf plasma vapor deposition process, inductively-coupled, using tetrafluoroethylene as the monomer gas.

The study aimed toward effecting variable surface properties of the film deposits via plasma process parameters and gas feed admixtures. In addition, the nature and structure of the fluorocarbon deposits were elucidated using surface property characterization and ESCA techniques.     

Solvent-Free Synthesis of Dihydropyridines and Acridinediones via a Salicylic Acid–Catalyzed Hantzsch Multicomponent Reaction

A multicomponent Hantzsch synthesis of 1,4-dihydropyridines and acridinediones from commercially available aldehydes, ammonium acetate, and ethyl acetoacetate or dimedone, in the presence of salicylic acid as an efficient catalyst, in good yield and short reaction time is reported.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

First Synthesis of Dopamine and Rotigotin Analogue 2-Amino-6,8-dimethoxy-1,2,3,4-tetrahydronaphthalene

The title compound was synthesized starting from 3-(3,5-dimethoxyphenyl)acrylic acid in 11 steps with 30% total yield. The reaction sequence hydrogenation of acrylic acid, reduction of acid to alcohol derivative with LiAlH₄, reaction of alcohol with CBr₄/PPh₃, substitution reaction of alkyl halide to nitrile derivative with NaCN, hydrolysis of nitrile with NaOH, cyclization reaction of acid with PPA to give 1-tetralone, α-carboxylation of tetralone with Me₂CO₃ in the presence of NaH, reduction of ketone group with Et₃SiH, hydrolysis of ester, Curtius rearrangement of acid with diphenylphosphoryl azide followed by conversion to carbamate, and finally hydrogenolysis of carbamate afforded 2-amino-6,8-dimethoxy-1,2,3,4-tetrahydronaphthalene hydrogen chloride salt.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of a Series of Hydroxycarboxylic Acids as Standards for Oxidation of Nonanoic Acid

The synthesis of a series of nonanoic acids hydroxylated in terminal,ω-1,ω-2,ω-3 positions is described. These compounds will be employed as useful standards for the study of enzymatic and microbiological oxidation of nonanoic acid.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

An Expedient Approach for the Synthesis of 1-Alkyl-4-propionylpyrrolidin-2-ones

A simple and useful tandem addition–cyclization reaction of primary amines on a prepared α-functionalized propylvinyl ketone 3 in methanol at reflux is a promising route for the synthesis of a new family of 1-alkyl-4-propionylpyrrolidin-2-ones 4.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]