Efficient Synthesis of 1,3,5-Benzotriazocines from Tetrachloro-2-aza-1,3-dienes

Easily accessible 1-aryl-2-aza-1,3-butadienes undergo a regioselective cyclocondensation with 2-(aminomethyl)aniline, giving rise to 1,3,5-benzotriazocines in good yields. The structure of the title compounds was proved with the aid of ¹H and ¹³C NMR spectra and, in one case, single-crystal x-ray 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 and Insecticidal Activities of Tetrahydroimidazo[1,2-a]pyridinones: Further Exploration on cis-Neonicotinoids

cis-Neonicotinoid, in which the nitro and cyano pharmacophore point to the same position relative to the heteroaromatic moiety, is a further extension of the neonicotinoid library. While seeking new cis-neonicotinoid candidates, a series of tetrahydroimidazo[1,2-a]pyridinone derivatives were synthesized by reactions of nitromethylene analogs with itaconic anhydride. All the compounds were confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectroscopy. The target compounds had excellent insecticidal activities against cowpea aphids (Aphis craccivora) and brown planthopper (Nilaparvata lugens). Against armyworm, most of the compounds showed moderate activities. Interestingly, compound 12p was active against Tetranychus cinnabarinus. The synthesized compounds displayed good insecticidal activities against different insect species, which might provide useful guidance for further design of cis-neonicotinoid candidates.

[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.]     

Efficient Synthesis of Some New 2,3-Dimethylquinoxaline-1-oxides Using Bis(acetoxy)phenyl-λ 3-iodane as an Oxidant

A series of 2-(arylimino)-3-(hydroxyimino)butanes 3a–g, easily accessed by the condensation of variously substituted anilines 1a–g with biacetyl monoxime 2, were efficiently cyclized to afford 2,3-dimethylquinoxaline-1-oxides 4a–g using bis(acetoxy)phenyl-λ ³-iodane as an oxidant. This methodology utilizes a commercially available and environmental benign oxidant to achieve the title compounds in excellent yields 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.]     

Synthesis and Spectral and Electrochemical Characterization of Novel Substituted 1,4-Naphthoquinone Derivatives

The novel substituted 2,3-dichloro-1,4-naphthoquinone derivatives were synthesized from the reactions of (1) and related nucleophilles in sodium carbonate (Na₂CO₃) solution of ethanol, chloroform with Et₃N, or potassium carbonate (K₂CO₃) solution of acetonitrile. The structures of novel compounds were characterized by using microanalysis, Fourier transform–infrared, ¹H NMR, ¹³C NMR, mass spectrometry, and cyclic voltammetry (CV).

[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 3-(2-(4,5-Dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one Derivatives via Multicomponent Approach

An efficient synthesis of 3-(2-(4,5-dihydro-3,5-diphenylpyrazol-1-yl)thiazol-4-yl)-2H-chromen-2-one derivatives by a simple, atom-economical, and multicomponent reaction of chalcones, thiosemicarbazide, and 3-(2-bromoacetyl) coumarins in the presence of aqueous sodium hydroxide in refluxing ethanol is reported. The structures of newly prepared compounds have been confirmed by their analytical and spectral (IR, ¹HNMR, ¹³CNMR and mass) data.

[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.]     

Efficient Synthesis of Readily Water-Soluble Amides Containing Sulfonic Groups

A series of various readily water-soluble amides were synthesized by different procedures. These compounds are useful chemical tracers for assessing the cooling progress in a georeservoir during geothermal power plant operation. Acylation of primary amines was carried out by basically employing the Schotten–Baumann method. As a second method a single-phase solvent system consisting of ethyl acetate as an organic solvent and triethylamine as a catalyst was used. Products were characterized by ¹H NMR and ¹³C NMR.

[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,Antibacterial, and Antifungal Activities of Imidazo[2,1-c][1,2,4]triazoles and 1,2,4-Triazolo[4,3-a]pyrimidinones

A straightforward method has been developed for the synthesis of 1-phenyl-imidazo [2,1-c][1,2,4]triazole derivatives 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones derivatives 6a–g starting from 5-amino-1-phenyl[1,2,4]triazole and p-toluenesulfonic acid (PTSA). This methodology affords a number of 1-phenyl-imidazo [2,1-c][1,2,4]triazoles 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones 6a–g in reasonable yields and short reaction times. The structures of all new compounds were elucidated using infrared, ¹H and ¹³C NMR, and high-resolution mass spectrometry. Some of the newly synthesized compounds were screened for their antimicrobial activity.

[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.]     

Three-Component Synthesis and 1,3-Dipolar Cycloaddition of Highly Functionalized Pyrans with Nitrile Oxides: Easy Access to 1,2,4-Oxadiazoles

Three-component reaction of 1-[(4-chlorophenyl)sulfanyl]acetone, malononitrile, and substituted aromatic aldehydes in the presence of sodium ethoxide under simple mixing at ambient temperature for 5–8 min afforded highly functionalized 4H-pyrans in good to excellent yields. 1,3-Dipolar cycloaddition of nitrile oxides over the nitrile functionality of the 4H-pyrans furnished 1,2,4-oxadiazoles in moderate yields.

Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for full experimental and spectral details.     

Stereoselective Synthesis of (Z)-1-Benzhydryl-4-cinnamylpiperazines via the Wittig Reaction

A synthetic method of producing (E)- and (Z)-isomers of 1-benzhydryl-4-cinnamylpiperazines in a specific ratio from corresponding benzhydrylpiperazine is described. Of the three compounds synthesized (5a–c), the ratio of E/Z-isomers remained around 15:85. The key intermediates, 1-benzhydryl-4-(2,2-dimethoxyethyl)piperazine derivatives (3a–c), were prepared by nucleophilic substitution reaction of benzhydrylpiperazines (2a–c) with chloroacetaldehyde dimethylacetal in good yield (up to 88%). Hydrolysis of 3a–c gave the corresponding aldehydes 4a–c, which when subjected to the Wittig reaction followed by column purification to afford 1a–c (E-isomers) and 6a–c (Z-isomers) in pure form. The isolated compounds were characterized by NMR and mass spectral 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.]     

Trifluoroacetic Acid–Catalyzed Synthesis of N-(1-(3-Chlorophenyl)-3-aryl-3-oxopropyl)-2-(4-nitrophenyl)acetamides via Dakin–West Reaction

A series of novel N-(1-(3-chlorophenyl)-3-aryl-3-oxopropyl)-2-(4-nitrophenyl) acetamides were synthesized using p-nitrophenylacetonitrile, m-chlorobenzaldehyde, and aryl methyl ketones as starting materials and trifluoroacetic acid (TFA) as catalyst. This realized an improved Dakin–West reaction in which p-nitrophenylacetonitrile was involved. The chemical structures of up to 15 target molecules were characterized by ¹H NMR, ¹³C NMR, and high-resolution mass spectrometry. This method provides a facile synthetic protocol under more moderate reaction conditions, smaller dosage (0.40 mol%) and hence lower cost of catalyst, and simpler posttreatment in comparison to other known methods. A reaction mechanism is proposed in which hydroxyacetophenone is first catalytically converted into the corresponding acetoxyacetophenone prior to be involved in the subsequent Dakin–West reaction that eventually leads to hydroxyl-acetylated target compounds.

[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.]     

Cyclocondensation of Thioamides and Haloacetic Acid Derivatives Provides Only 4-Thiazolidinones; Isomeric 5-Thiazolidinones Were Not observed

Cycloaddition of intermediates formed from the nucleophilic addition of aryl isothiocyanate to acidic cyanomethylenes and α-halocarbonyl compounds gave only 4-thiazolidinones. 5-Thiazolidinones were not observed. Cyano-(4-oxo-3-phenylthiazolidin-2-ylidene)-acetic acid ethyl ester (1) and cyano-[5-(4-methoxybenzylidene)-4-oxo-3-phenylthiazolidin-2-ylidene]-acetic acid ethyl ester (2a) also were shown to exhibit moderate antiviral activity.

[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.]     

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.]     

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.]     

Total Synthesis of (±)-Glabridin

An efficient formal synthesis of (±)-glabridin was accomplished in 10 steps from resorcinol using Raney Ni to reduce carbon–carbon double bonds in α,β-unsaturated carbonyl compound as the key step.

[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.]     

Direct Arylation of Adenine by Fluoro- and Chloronitrobenzenes: Effect of Microwaves

Direct arylation of adenine with fluoro- and chloronitrobenzenes leads to mixtures of N9 and N7 substituted adenines. After separation by column chromatography, the individual isomers can be efficiently hydrogenated on Pd to give the corresponding aminophenyladenines. A significant enhancement of the reaction rate by microwave irradiation was observed. This two-step procedure was found to be a feasible route to otherwise hardly available 7-aminophenyladenines. Correlation between calculated shielding constants and experimental values of chemical shifts in ¹³C and ¹⁵N NMR was used for assignment of the site of substitution.

[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.]     

Selection of Amino Acids and the Biomimetic Synthesis of Amido Bond in the Presence of β-CD

A new method was developed to construct a special amido bond in the presence of β-cyclodextrin. This process is similar to peptide synthesis in organisms. NMR experiments were performed to investigate the possible mechanism. This work has potential application in biomimetic peptide synthesis.

[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.]     

Oxidative Nuclear Bromination of Substituted 4-Pyridones Using Pyridinium Bromochromate

An alternative convenient approach for the bromination of various poly-substituted 4-pyridones has been developed via an oxidative nuclear bromination in the presence of sole pyridinium bromochromate (PBC). The PBC performs the dual role of oxidant and source of Br⁺ during the process.

[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 Diastereoselective Vinylogous Mukaiyama Aldol Reaction of Isatins with 2-(Trimethylsilyloxy)furans Catalyzed by Quinine

The diastereoselective formation of δ-hydroxyalkyl butenolide oxindoles has been achieved via a vinylogous Mukaiyama aldol reaction. The reaction was performed using various (N-alkyl)isatins 1 with 2-(trimethylsilyloxy)furan 2 catalyzed by quinine in tetrahydrofuran (THF). The reaction proceeds rapidly and affords the corresponding 3-hydroxy-(5-oxo-2,5-dihydrofuran-2-yl)indolin-2-ones in good yields with high diastereoselectivities (anti/syn ratio up to 96:4).

[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.]