Simple,Multicomponent, Ecofriendly,Microwave-Mediated Route for the Synthesis of Antimicrobial 2-Amino-6-aryl-4-(3H)-pyrimidinones

In this work, we describe a multicomponent microwave-mediated synthesis of 10 2-amino-6-aryl-4-oxo-1,6-dihydro-pyrimidine-5-carbonitriles in good chemical yields (44–67%), four of them not related in earlier literature. All pyrimidinones synthesized herein had their antimicrobial activity evaluated against the following microorganisms: Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Two of the synthesized substances displayed good antimicrobial activity against P. aeruginosa and S. aureus, two bacteria responsible for nosocomial infections.

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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.

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Vilsmeier Reagent: An Efficient Reagent for the Transformation of 2-Aminobenzamides into Quinazolin-4(3H)-one Derivatives

Clean and easy preparation of quinazolin-4(3H)-one derivatives using 2-aminobenzamides and Vilsmeier reagent is described. 2-Aminobenzamides were converted into the corresponding quinazolinones under mild and efficient conditions, in good yields without undesirable by-products.

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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.]     

Simple and Efficient Method for the Synthesis of 1-((Aryl)(2-oxoindolin-3-yl-)methyl)urea and 1-((Aryl)(2-oxoindolin-3-yl-)methyl)thiourea Derivatives

A number of new1-((aryl)(2-oxoindolin-3-yl)methyl)urea and 1-((aryl)(2-oxoindolin-3-yl)methyl)thiourea derivatives have been prepared by simply combining 2-indolinone, aromatic aldehyde, and urea or thiourea in the presence of p-TsOH in EtOH. This new methodology affords the title compounds in good yields and without the use of chromatography.

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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.

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Solvent-Free Microwave-Assisted Preparation of N-(2-(Pyridin-2-yl)-ethyl)sulfonamides

Although nitrogen-containing heterocycles and sulfonamides both play crucial roles in the chemical and pharmaceutical industries, surprisingly little research exists that examines the bifunctional N-(2-(pyridin-2-yl)ethyl)sulfonamide scaffold for any potential applications. Retrosynthetic analysis indicates that this skeleton would be well suited for a conjugate addition reaction. However, the ability of 2-vinylpyridine to behave as an acceptor, and of sulfonamides to behave as donors, has very limited literature precedent, and thus required some preliminary investigations into their mutual reactivity. Herein outlines our laboratory's discovery of a novel and efficient solvent-free 1,4-aza-conjugate addition reaction between sulfonamides and 2-vinylpyridines that provides expedient access to various N-(2-(pyridin-2-yl)ethyl)sulfonamide derivatives. The products, possessing multiple sites of Brønsted acidity and basicity in close proximity, could display a wide array of valuable host–guest properties and should thus be investigated for potent pharmaceutical or agrochemical properties.

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Improved Synthesis of 10-(2-Alkylamino-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic Acid Derivatives Bearing Acid-Sensitive Linkers

Alkylation of the hydrobromide salts of 1,4,7-tris(methoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane and 1,4,7-tris(ethoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane with appropriate α-bromoacetamides, followed by hydrolysis, provides convenient access to 10-(2-alkylamino-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid derivatives that contain acid-sensitive functional groups. The utility of the method is demonstrated by improved syntheses of two known 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid monoamides bearing acid-sensitive ω-tritylthio alkyl chains in much greater yields based on cyclen as the starting material.

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Orthogonally Positioned Diamino Pyrrole- and Imidazole-Containing Polyamides: Synthesis of 1-(3-Substituted-propyl)-4-nitropyrrole-2-carboxylic Acid and 1-(3-Chloropropyl)-4-nitroimidazole-2-carboxylic Acid

Pyrrole- and imidazole-containing polyamides can be tailored to recognize the DNA 6–8 base pair sequence. We found that adding a second amino group via the N1-position of pyrrole or imidazole in polyamides could enhance their DNA binding affinity and water solubility while retaining sequence specificity. Synthesis of the key 1-substituted-4-nitropyrrole (and imidazole)-2-carboxylic acid building blocks are described.

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Novel,Recyclable, and Thermally Stable Task-Specific Ionic Liquid (TBA Acetate) Medium/Catalyst for the Synthesis of Indolylidinecyclic-1,3- and -1,4-diketones

A simple and efficient synthesis of indolylidinethiazolidnediones (3) and indolylidinecyclic-1,3-diketones (5) has been developed by reaction of indole-3-aldehyde (1) with thiazolidinedione (2) or cyclic-1,3-diketones (4) using tetra butyl ammonium acetate (TBAA) melt as novel, cost-effective, and recyclable ionic liquid under solvent-free green conditions at 100 °C for 15–20 min without additional use of catalyst.

[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).

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Evaluation of Baylis–Hillman Routes to 3-(Aminomethyl)coumarin Derivatives

The relative merits of two different Baylis–Hillman approaches toward the preparation of coumarin derivatives, containing peptide-like side chains, have been explored. In one approach, use of methyl acrylate as the activated alkene requires a protecting group strategy, an approach that is not necessary when using tert-butyl acrylate.

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Efficient Mo(VI)-Catalyzed Hydration of Nitrile with Acetaldoxime

A method for the selective hydration of nitrile to amide by employing commercially available acetaldoxime and inexpensive oxometallate such as molybdate, vanadate, and tungstate in environmentally friendly water is described. Under this protocol, nitriles including aromatic nitriles, heterocyclic nitriles, and aliphatic nitriles were converted into the corresponding amides in good to excellent yields.

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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.]     

Novel One-Pot Multicomponent Synthesis of Substituted 2,3-Dihydro-2-(6-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phthalazine-1,4-diones and Substituted 3-[3-(N′-Benzylidene-hydrazino)-7H-[1,2,4] triazolo[3,4-b][1,3,4]thiadiazin-6-yl]-4-hydroxy-6-methyl-pyran-2-ones

A one-pot procedure has been developed for the synthesis of substituted 2,3-dihydro-2-(6-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-7H-[1,2,4]triazolo[3,4-b] [1,3,4]thiadiazin-3-yl)phthalazine-1,4-diones by reaction of 3-(2-bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, 4-amino-5-hydrazino-4H-[1,2,4]triazole-3-thiol, and phthalic anhydrides in acetic acid medium. Similarly, a one-pot, three-component synthetic procedure has been developed for substituted 3-[3-(N¹-benzylidene-hydrazino)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-yl]-4-hydroxy-6-methyl-pyran-2-ones from 3-(2-bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, 4-amino-5-hydrazino-4H-[1,2,4]triazole-3-thiol, and various aromatic aldehydes in absolute ethanol and a few drops of glacial acetic 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.]     

One-Pot Microwave-Assisted Synthesis of 3,4-Disubstituted 2-Quinolinones

An improved one-pot synthesis of 3,4-disubstituted 2-quinolinones is described. The condensation of substituted 2-aminobenzophenone (or 2-aminophenyl alkyl ketone) with acid chlorides was carried out in the presence of triethylamine (or NaH) under microwave reaction conditions (150oC, 200 psi). The reactions were completed within minutes to produce 2-quinolinones in moderate to excellent yields and good purities.

[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.]