A One‐pot Green Synthesis of Alkylidenesuccinimides

A mild and facile Wittig reaction between N‐substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one‐pot reaction in high yields (up to 99%). The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment‐benign solvent, was found to be a suitable reaction medium.     

Catalyst‐free,Knoevenagel–Michael Addition Reaction of Dimedone under Microwave Irradiation: An Efficient One‐pot Synthesis of Polyhydroquinoline Derivatives

Present investigation reports a concise and efficient protocol for the synthesis of polyhydroquinoline derivatives through coupling of four different components viz. aromatic aldehydes, dimedone, ethyl acetoacetate or ethyl cyanoacetate, and ammonium acetate. The same phenomenon can be observed using arylmethylene bis(3‐hydroxy‐2‐cyclohexene‐1‐ones), ethyl acetoacetate, and ammonium acetate in one pot under microwave irradiation. The key advantages of the given protocol include short reaction time, high yields, and simple work‐up and purification procedure. The present method also allows us to synthesize highly functionalized title compounds from simple and readily available starting materials.     

Synthesis of Novel Chromene,Pyridine, Pyrazole,Pyrimidine, and Imidazole Derivatives via One‐pot Multicomponent Reaction

New series of chromenes 2 – 4 , pyridines 5 – 8 , and pyranopyrazoles 9a,b were synthesized via one‐pot multicomponent reaction of 4‐tosyloxybenzaldehyde ( 1 ) and malononitrile with phenols, amines or hydrazines, and ethyl acetoacetate, respectively. Compound 9a was reacted with acetic anhydride, formic acid, or formamide to afford N ‐acetyl derivative 10 and pyrazolopyranopyrimidines 11 – 13 , respectively. Imidazole derivatives 14 and 15a – d were obtained by multicomponent reaction between compound 1 with ammonium acetate and benzil or aromatic amines in (1:2:1) or (1:1:1:1) ratio, respectively. The structures of new compounds were elucidated by elemental and spectral analyses.     

One‐pot Synthesis of Fused Dipyranocoumarins from Dihydroxycoumarins and Propargyl Chlorides under Microwave Irradiation

Dipetalolactone and 4‐methyldipetalolactone are prepared in excellent yield by a one‐pot tandem propargylation/Claisen rearrangement/cyclization reaction of the corresponding 5,7‐dihydroxycoumarins with 3‐chloro‐3‐methylbut‐1‐yne in the presence of Cs₂CO₃ under microwave irradiation. The analogous reactions of propargyl chloride with esculetins or 5,7‐dihydroxycoumarins led to dipropargyloxy derivatives. The later by treatment with gold nanoparticles supported on TiO₂ or BF₃.Et₂O in N,N‐dimethylformamide (DMF) under microwave irradiation resulted in very good to excellent yield to the corresponding fused dipyranocoumarins. The reactions of esculetins with 3‐chloro‐3‐methylbut‐1‐yne gave mainly exomethylene fused dioxino[g]coumarins.     

A Facile Synthesis of New L‐Proline‐Based Trifluoromethyl Oxazole Derivatives Using Microwave Irradiation and Conventional Method

Cyclization reaction of l ‐proline with trifluoroacetimidoyl chlorides has been developed as an efficient strategy for the synthesis of trifluoromethyl oxazole derivatives by two methods: (a) in the presence of K₂CO₃ as a base in acetonitrile at room temperature and (b) in the presence of K₂CO₃ as a base in acetonitrile using microwave irradiation, in one pot reaction. The microwave irradiation has been found to be the most efficient method. High yields and short reaction times were obtained for both electron‐releasing and electron‐withdrawing substituted N‐aryltrifluoroacetimidoyl chloride derivatives by microwave irradiation.     

A Novel Method for One‐pot Synthesis of Furo[3,2‐c]coumarin Derivatives from 4‐Hydroxycoumarin and Arylglyoxal under Microwave Irradiation

A novel one‐pot synthesis of furo[3,2‐c]coumarins has been developed from readily available starting materials 4‐hydroxycoumarin and arylglyoxal. This method is simple, rapid and good yielding.     

An Efficient One‐Pot,Multicomponent, and Green Solvent Protocol for the Synthesis of Dihydropyridine Derivatives

Highly prominent dihydropyridine analogs have been developed and screened for their yields by using different catalysts under eco‐friendly ethanol solvent condition. Triethylamine catalyst was identified as ro bust catalyst for this synthetic path. The key benefits of this procedure are environmentally benign procedure, mild reaction conditions, simplicity of operation, high yields, mild reaction period, and decent substrate generality.     

An Efficient One‐Pot Synthesis of New Coumarin Derivatives as Potent Anticancer Agents under Microwave Irradiation

An efficient and rapid synthesis of coumarin derivatives was accomplished via reactions of 3‐(3‐(4‐methoxyphenyl)acryloyl)‐2H ‐chromen‐2‐one ( 3 ) with different carbon nucleophiles such as ethyl acetoacetate, ethyl cyanoacetate, malononitrile, and ethyl benzoylacetate via conventional heating and microwave irradiation conditions and were used as source of pyran and pyridine derivatives bearing coumarin moiety 4 – 11 . Compound 9a was condensed with different carbon electrophiles triethylorthoformate, phenylisothiocyanate, carbon disulfide, benzoylchloride, and acetylchloride that afforded the corresponding chromen derivatives 12 – 16 . All the newly synthesized compounds were characterized by elemental and spectroscopic evidences. All of synthesized compounds were tested for in vitro cytotoxicity. The preliminary screening results showed that most of the compounds had moderate cytotoxic activity against HCT‐116 and MCF‐7 cell lines. Nevertheless, compound 10 exhibited potent activity against the two cell lines, which was comparable with the standard drug 5‐fluorouracil.     

Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation

One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO₃ have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism.     

Synthesis,Characterization, and Antibacterial Activity of Some Novel Substituted Imidazole Derivatives via One‐pot Three‐Component

A simple and highly efficient one‐pot, three‐component synthesis of novel substituted imidazole derivatives has been reported by the reaction of 3‐(2‐bromoacetyl)‐2H‐chromen‐2‐one, ammonium thiocyanate, and phenacyl aniline in the presence of acetic acid as a solvent under reflux condition with good yields. The structures of newly synthesized compounds were characterized by their analytical and spectral data. One of these compounds 4a showed good antibacterial activity against Escherichia coli gram‐negative strains.     

Green Synthesis of 1,2,4,5‐Tetrasubstituted and 2,4,5‐Trisubstituted Imidazole Derivatives Involving One‐pot Multicomponent Reaction

Sodium lauryl sulfate has been found convenient, versatile, and eco‐friendly catalyst for the synthesis of 1,2,4,5‐tetrasubstituted and 2,4,5‐trisubstituted imidazole derivatives by one‐pot multicomponent reactions at 80°C using water as solvent. This protocol afforded advantages, that is, the metal‐free reaction, purification of products by non‐chromatographic method, and excellent yields.     

One‐pot Synthesis and Characterization of Gold‐nickel Bimetallic Nanorods

This report focuses on the synthesis of gold‐nickel bimetallic nanostructures. In the presence of amine as the capping agent, thermal decomposition of organometallic precursors CH₃AuPPh₃ and Ni(PPh₃)₄ in o‐xylene offered AuNi nanorods. Several preparative parameters possible influencing the morphology of the structure were carefully studied by varying the reaction conditions with respect to the standard procedure. The morphology and composition of the AuNi nanorods were principally characterized by transmission electron microscopy, energy dispersive spectroscopy, and powder X‐ray diffraction. The distribution of the Au as well as Ni atoms was examined by EDS mapping analysis. The mechanism of the formation of the AuNi bimetallic nanorods is proposed on the base of observation of the morphologies of nanostructures at various reaction time intervals.     

Retracted: Microwave Assisted Synthesis of Trifluoro Substituted 2‐Aminobenzimidazole Derivatives via Iodoacetic Acid Mediated One‐pot Condensation

Microwave‐assisted efficient one‐pot syntheses of trifluoro substituted 2‐aminobenzimidazole derivative were synthesized using iodoacetic acid mediated cyclodesulfurization of thioureas. This method eliminates need to handle preformed substituted thioureas, requires lesser reaction time and temperature, is facile, and also gives higher yields of the target molecules.     

A Convenient Synthesis of Pyrazole‐imidazoline Derivatives by Microwave Irradiation

A series of 28 hybrids pyrazole‐imidazolines 1a – n and 2a – n were synthesized by a new methodology using microwave irradiation, in short time (20–30 min), in low power (50–70 W), and in 34–92% yield. Among all methodologies evaluated, no side products were obtained. All derivatives were completely characterized by FT–IR, ¹H and ¹³C NMR, GC–MS, and HRMS.     

One‐pot Green Synthesis of Pyrrole Derivatives Catalyzed by Nano Sulfated Zirconia as a Solid Acid Catalyst

A new and efficient method for the preparation of N‐substituted pyrroles from one‐pot Paal‐Knorr condensation has been accomplished using nano‐crystalline sulfated zirconia (SZ) as the catalyst in ethanol at moderate temperature. This new protocol has the advantages of easy availability, stability, reusability and eco‐friendliness of the catalyst, high to excellent yields, simple experimental and work‐up procedure. The synthesized compounds were confirmed through spectral characterization using IR, ¹H NMR, ¹³C NMR and mass spectra.     

A Mild and Simple One‐pot Synthesis of 2‐Substituted Benzimidazole Derivatives Using DDQ as an Efficient Oxidant at Room Temperature

A series of 2‐substituted benzimidazoles were prepared through one‐pot reaction of o‐phenylenediamine with various aryl aldehydes in the presence of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) in acetonitrile as solvent at room temperature. The reactions were smoothly preceded in excellent yields and short reaction times with an easy work‐up. The pure benzimidazoles as products were confirmed and characterized by physical and spectral data.     

A Simple,Efficient One‐Pot Synthesis of 2‐Isoxazoline Derivatives and their Antimicrobial Activity

Synthesis of substituted 2‐isoxazolines derivatives with sulfone functional groups was accomplished by 1,3‐dipolar cycloaddition reaction. The 1,3‐dipolar nitrile oxides generated in situ by reacting α‐formaldoximes with N‐bromosuccinimide in the presence of triethylamine on reaction with activated alkenes in toluene at room temperature afford the corresponding 2‐isoxazolines in high yields. All the 2‐isoxazoline derivatives were assayed for their antibacterial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa and antifungal activities against Aspergillus niger and Candida albicans. Most of the compounds showed good antibacterial and antifungal activities.     

4‐Hydroxy‐1‐phenylquinolin‐2(1H)‐one in One‐pot Synthesis of Pyrimidoquinolines and Related Compounds under Microwave Irradiation and Conventional Conditions

Biginelli condensation reactions of 4‐hydroxy‐1‐phenylquinolin‐2(1H)‐one, aryl aldehydes and urea, or thiourea, 5‐amino‐1H‐1,2,4‐triazole, or 2‐amine‐1H‐benzimidazole ( 9 ) under microwave irradiation afforded the corresponding pyrimido[5,4‐c]quinolin‐5‐one derivatives in high yields. One‐pot synthesis of 2H‐pyrano[3,2‐c]quinolines is also reported.     

A Novel One‐Pot Method for the Synthesis of Pyrimidine Derivatives Using Ketene N,S‐Acetal with Aryl Aldehydes

A very simple and facile one‐pot method for the synthesis of pyrimidine derivatives is presented. In this method, 2‐aryl‐pyrimidine derivatives were prepared by the reaction of ketene N,S‐acetal 1 with commercially available aryl aldehydes by heating under solvent and catalyst‐free conditions. The synthesized pyrimidine derivatives showed blue‐green fluorescence in solid state.