Zeolite‐Supported One‐Pot Synthesis of Bis‐azetidinones under Microwave Irradiation

In an attempt to synthesize antibacterial agents effective against gram‐positive and gram‐negative bacteria, the efficient synthesis of novel bis‐azetidinones ( 3a–j ) has been established. Thus, cycloaddition reaction of substituted bis‐imines with chloroacetylchloride under microwave irradiation in the presence of zeolite yielded bis‐azetidinones ( 3a–j ). Structures of the synthesized compounds have been elucidated on the basis of their elemental analysis and spectral data (IR, ¹H‐NMR, ¹³C‐NMR, and mass spectra). The synthesized bis‐azetidinones were screened for their antibacterial activity against five microorganisms: Bacillus subtilis, Proteus vulgaris, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. They were found to exhibit good to moderate antibacterial activity.     

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.     

Seed‐Assisted,One‐Pot Synthesis of Hollow Zeolite Beta without Using Organic Structure‐Directing Agents

Hollow aluminosilicate zeolite beta was successfully synthesized by adding CIT‐6, that is, zincosilicate zeolite, which has the same topology as beta, as seeds to the Na‐aluminosilicate gel without the need for organic structure‐directing agents. One important factor in the successful organic structure‐directing agent (OSDA)‐free synthesis of hollow beta crystals is the solubility of the seed crystals in alkaline media. CIT‐6 was less stable than aluminosilicate zeolite beta in alkaline media and the solubility changed depending on whether the crystals were calcined or not. The hollow beta could be obtained by using the uncalcined CIT‐6 seed crystals. The volumes of intra‐crystalline voids were tuned by changing the reaction time and the initial gel compositions, such as the SiO₂/Al₂O₃ and Na₂O/SiO₂ ratios. We estimated that the intra‐crystalline voids were formed through the dissolution of the seed crystals, just after the crystal growth of new beta on the outer surface of the seeds. In addition, new crystal growth toward inside of the void was also observed by TEM. On the basis of the characterization data, such as chemical analysis, N₂‐adsorption/desorption measurements, and TEM observation, a formation mechanism of the intra‐crystalline voids is proposed and discussed.     

Ultrasound Assisted Synthesis of Some Novel Bis‐Pyridazine Derivatives

Bis‐enaminone 3 was coupled with aryldiazonium chlorides 4a , 4b to afford the bis‐arylhydrazonopropanals 6a , 6b . Compounds 6a , 6b could be utilized for the synthesis of a variety of bis‐(dimethyl 2,3‐dihydropyridazine‐3,4‐dicarboxylate), bis‐(pyridazin‐3(2H)‐one), bis‐(2,3‐dihydropyridazine‐4‐carbonitrile) and bis‐(3‐imino‐2,3‐dihydropyridazine) derivatives, under ultrasonic irradiation. A comparative study of aforementioned reactions was carried out under conventional method as well as under ultrasonic irradiation conditions.     

Metal‐Assisted One‐Pot Synthesis of Isoporphyrin Complexes

Zinc and cadmium complexes of meso‐arylisoporphyrins carrying a pyrrolyl or dipyrrinyl substituent at the sp³ carbon atom were obtained through a simple one‐pot variation of the Alder–Longo porphyrin synthesis. Key to the formation and stabilization of isoporphyrins is the presence of metal acetates during the oxidative macrocyclization step. The characteristic Q‐bands of isoporphyrins are found in the NIR region between 750 nm and 880 nm. All of the isolated pyrrolyl‐ and dipyrrinyl‐appended isoporphyrins are stable under typical laboratory conditions and allow chemical transformations like BF₂ coordination, transmetalation, and ligand exchange.     

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.     

Tandem One‐pot Synthesis of Polysubstituted 1,3‐Thiazine Derivatives

A tandem one‐pot synthesis of polysubstituted 1,3‐thiazines has been developed by reacting with cyanoacetamide and isothiocyanate derivatives to give rise to 2‐cyano‐3‐mercaptoacrylamides, which are trapped in situ by various aldehydes or diversely substituted ketones through intermolecular cyclization, providing polysubstituted 1,3‐thiazine derivatives in short reaction times with good to excellent yields. The salient features of this novel protocol are operational simplicity, accessing the desired products from the readily available starting materials and easy of product isolation and may find wide spread applications in medicinal chemistry.     

An Efficient and Easy Method for the One‐pot Synthesis of Spirooxindoles in the Presence of Na2CO3

An efficient and easy procedure for the one‐pot synthesis of spirooxindoles in the presence of Na₂CO₃ in water : methanol (1:1) is described. The salient features of this method are simple methodology, shorter reaction time, easy product isolation, and no chromatographic purification.     

Ultrasound‐Assisted Synthesis of Hybrid Vanadium Oxide/Polyaniline Nanowires

A single‐step sonochemical procedure to synthesize hybrid vanadium oxide/polyaniline nanowires starting from crystalline V₂O₅ and aniline in aqueous medium is presented. The synthesis explores the effect of high power ultrasounds on heterogeneous solid–aqueous phases, which leads to 30 nm width wires of 5 to 10 µm in length. Monomer intercalation and oxidative polymerization within the inorganic matrix proceed simultaneously with morphological changes. The electronic conductivity of hybrid nanowires reaches 0.8 S · cm⁻¹ at room temperature.

     

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.     

Efficient Microwave‐assisted One‐pot Synthesis of Novel Spironaphthopyrano‐one Derivatives

Rapid and efficient one‐pot three‐component synthesis of new spironaphthopyrano‐one derivatives by cyclocondensation reaction in aqueous media is achieved under microwave irradiation conditions. This protocol has the advantages of higher yield, lower cost, reduced time, environmental impact, and convenient procedure.     

Ultrasound‐Assisted One‐Pot Synthesis of Octahydroquinazolinone Derivatives Catalyzed by Acidic Ionic Liquid [Tbmim]Cl2/AlCl3

Acidic ionic liquid [tbmim]Cl₂/AlCl₃ catalysed an efficient synthesis of octahydroquinazolinone derivatives under ultrasound‐irradiation. This method provides several advantages such as environment benign, high yields and simple work‐up procedure.     

Multicomponent One‐pot Reactions Towards the Synthesis of Stereoisomers of Dipicolylamine Complexes

Reported are multi‐component one‐pot syntheses of chiral complexes [M(L^ROR′)Cl₂] or [M(L^RSR′)Cl₂] from the mixture of an N‐substituted ethylenediamine, pyridine‐2‐carboxaldehyde, a primary alcohol or thiol and MCl₂ utilizing in‐situ formed cyclized Schiff bases where a C?O bond, two stereocenters, and three C?N bonds are formed (M=Zn, Cu, Ni, Cd; R=Et, Ph; R′=Me, Et, nPr, nBu). Tridentate ligands L^ROR′ and L^RSR′ comprise two chiral centers and a hemiaminal ether or hemiaminal thioether moiety on the dipicolylamine skeleton. Syn‐[Zn(L^PhOMe)Cl₂] precipitates out readily from the reaction mixture as a major product whereas anti‐[Zn(L^PhOMe)Cl₂] stays in solution as minor product. Both syn‐[Zn(L^PhOMe)Cl₂] and anti‐[Zn(L^PhOMe)Cl₂] were characterized using NMR spectroscopy and mass spectrometry. Solid‐state structures revealed that syn‐[Zn(L^PhOMe)Cl₂] adopted a square pyramidal geometry while anti‐[Zn(L^PhOMe)Cl₂] possesses a trigonal bipyramidal geometry around the Zn centers. The scope of this method was shown to be wide by varying the components of the dynamic coordination assembly, and the structures of the complexes isolated were confirmed by NMR spectroscopy, mass spectrometry, and X‐ray crystallography. Syn complexes were isolated as major products with Zn^II and Cu^II, and anti complexes were found to be major products with Ni^II and Cd^II. Hemiaminals and hemiaminal ethers are known to be unstable and are seldom observed as part of cyclic organic compounds or as coordinated ligands assembled around metals. It is now shown, with the support of experimental results, that linear hemiaminal ethers or thioethers can be assembled without the assistance of Lewis acidic metals in the multi‐component assembly, and a possible pathway of the formation of hemiaminal ethers has been proposed.     

A One‐Pot Chemically Cleavable Bis‐Linker Tether Strategy for the Synthesis of Heterodimeric Peptides

Heterodimeric peptides linked by disulfide bonds are attractive drug targets. However, their chemical assembly can be tedious, time‐consuming, and low yielding. Inspired by the cellular synthesis of pro‐insulin in which the two constituent peptide chains are expressed as a single‐chain precursor separated by a connecting C‐peptide, we have developed a novel chemically cleavable bis‐linker tether which allows the convenient assembly of two peptide chains as a single “pro”‐peptide on the same solid support. Following the peptide cleavage and post‐synthetic modifications, this bis‐linker tether can be removed in one‐step by chemical means. This method was used to synthesize a drug delivery‐cargo conjugate, TAT‐PKCi peptide, and a two‐disulfide bridged heterodimeric peptide, thionin (7‐19)‐(24‐32R), a thionin analogue. To our knowledge, this is the first report of a one‐pot chemically cleavable bis‐linker strategy for the facile synthesis of cross‐bridged two‐chain peptides.     

Microwave‐Assisted One‐Pot Synthesis of Hyperbranched Epoxide‐Amine Adducts

Hyperbranched epoxide‐amine adducts were synthesized by a one‐pot microwave (MW) assisted reaction. 4‐(2,3‐epoxypropyl‐1‐oxy)benzonitrile was hydrogenated using Pd/C under microwave conditions, forming the AB₂ monomer 1‐aminomethyl‐4‐(2,3‐epoxypropyl‐1‐oxy)benzene. Depending on the reaction temperature this monomer immediately reacts to give hyperbranched epoxide‐amine adducts. Mass spectrometric investigations proved the formation of a homologous series of oligomers containing up to six repeating units. Due to the complexing properties of the poly(amino alcohol) moieties in the presence of Cu²⁺ ions, large aggregates were formed.

     

One‐pot Three‐component Synthesis of Furan‐based Heterocycles from Benzyl Halides

An efficient and a novel approach for the synthesis of furochromene and furopyran scaffolds are described. Benzyl halides undergo oxidation in Kornblum conditions to give the corresponding aldehydes, which in turn undergo [4 + 1] cycloaddition reaction with isocyanide to afford the corresponding furan derivatives. The significant attraction of this protocol is simple procedure, mild reaction condition, and good yield.     

One‐pot Synthesis of Novel Spirooxindoles as Antibacterial and Antioxidant Agents

The regioselective spiroindoline derivatives were afforded via multi‐componant reaction. Its process was one of the green chemistry (simplicity, mild conditions, and atomic economy). The electron repelling and attracting groups affected on reactivity of the azomethine ylides (increase E_HOMO value). All compound structures were confirmed by spectroscopic data and elemental analysis. The antibacterial and antioxidant activities for these synthesized compounds could be investigated; the highly antioxidant activity was observed with compounds, which proved to possess high HOMO values, and the highly antibacterial activity was observed against S . aureus , B . cereus , S . marcesens , and P . mirabilis , which proved to possess low HOMO values.     

Silica‐supported Perchloric Acid Catalyzed One‐pot Synthesis of 1,4‐Dihydropyridines

An environmentally friendly and highly efficient procedure for the preparation of 1,4‐dihydropyridines by the reaction between α,β‐unsaturated aldehydes, aromatic amines and β‐keto esters in the presence of silica supported perchloric acid is described.     

Microwave‐Assisted,One‐Pot Multicomponent Synthesis of Some New Cyanopyridines

An efficient and facile synthesis of cyanopyridines via a one‐pot four‐component reaction of aromatic aldehydes, acetophenones, malononitrile, or 2‐aminoprop‐1‐ene‐1,1,3‐tricarbonitrile in presence of sodium alkoxide or ammonium acetate under both microwave and thermal reaction conditions was introduced.     

One‐pot Modification of Terpene's Methylenecyclobutane Derivatives

Cycloalumination of terpene's methylenecyclobutane derivatives (d (+)‐camphor, (+)‐camphene, (?)‐β‐pinene, and l (?)‐menthol) with triethylaluminum catalyzed by Cp₂ZrCl₂ was accomplished for the first time to give previously undescribed spirocyclic organoaluminum compounds in high yields. The latter, without isolation, was converted into spirotetrahydroselenophanes or spirophospholanes.