An efficient multicomponent protocol for the stereoselective synthesis of oxazinobenzothiazole derivatives

An easy and efficient protocol for the stereoselective one-pot synthesis of oxazinobenzothiazole derivatives is described.     

An efficient one-pot synthesis of indolyl-4H-chromene derivatives

Chemistry of Heterocyclic Compounds - A new one-pot three-component reaction for the synthesis of indolyl-4H-chromene derivatives has been developed. The synthesis was achieved by reacting...     

An efficient protocol for the one-pot multicomponent synthesis of polysubstituted pyridines by using a biopolymer-based magnetic nanocomposite

A biopolymer cellulose-based magnetic composite nanocatalyst was prepared and characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Then, it was used efficiently in the multicomponent synthesis of polysubstituted pyridines under mild reaction conditions and using an easy work-up procedure at room temperature in ethanol. The nanocatalyst can be recovered easily and reused several times without significant loss of catalytic activity.     

A multicomponent reaction for the one-pot synthesis of 4-aza-2,3-didehydropodophyllotoxin and derivatives

[reaction: see text] A convergent method has been found to prepare 4-aza-2,3-didehydropodophyllotoxin and derivatives in a one-pot procedure. The mechanism of the reaction between tetronic acid, anilines, and benzaldehydes is discussed.     

A DMAP-catalyzed mild and efficient synthesis of 1,2-dihydroquinazolines via a one-pot three-component protocol

An efficient and simple method for the synthesis of 1,2-dihydroquinazolines catalyzed by 4-(N,N-dimethylamino)pyridine (DMAP) from readily available aromatic or heteroaromatic aldehydes, 2-aminobenzophenone, and ammonium acetate under mild conditions is described. The scope and limitations of the method are discussed.     

Convenient synthesis of fluorinated quinoline, 1,2-dihydroquinoline, and 1,2,3,4-tetrahydroquinoline derivatives

A convenient synthetic method for 2-polyfluoroalkylated quinoline systems through the efficient generation of perfluoroalkylated imine from o-vinylanilines with perfluorinated hemiacetals or aldehyde hydrates was developed. In most cases, the major products are 2-polyfluoroalkyl-1,2-dihydroquinoline derivatives 3, which can be converted to either quinolines or 1,2,3,4-tetrahydroquinolines.     

Efficient atom economical one-pot multicomponent synthesis of densely functionalized 4H-chromene derivatives

A sequential one-pot, atom economical three component reaction yielding medicinally promising ethyl 2-amino-3-cyano-4-(2-ethoxy-2-oxoethyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-4-carboxylate derivatives (4a-f) through a tandem Michael addition-cyclization reaction starting with structurally diverse cyclohexane-1,3-dione, diethyl acetylene dicarboxylate, and malononitrile has been carried out in different organic bases under solvent free condition for the optimization of maximum yield. All the formed 4H-chromenes were characterized by spectral and X-ray methods.     

Resin-bound 4-phenyl-1,2-dihydroquinoline (DHQ): a new safety-catch linker for solid-phase organic synthesis (SPOS)

A new safety-catch linker has been developed for combinatorial solid-phase chemistry. Azidomethyl-polystyrene, obtained by nucleophilic substitution of chloromethyl-polystyrene, undergoes an acid promoted Schmidt rearrangement. The resulting polymer-bound iminium participates in an aza Diels-Alder cycloaddition, which leads to a supported dihydroquinoline (DHQ resin). The acylated form of the DHQ resin is stable under basic, acidic and mild reducing agents. The cleavage proceeds in two steps (i) oxidative aromatization leading to an activated quinolinium and (ii) nucleophilic displacement of the quinoline resin. The overall process is high yielding and efficient.     

4-Hydroxy-2-quinolones. 152*. 3-acetyl-4-hydroxy-2-oxo-1,2-dihydroquinoline and its biologically active derivatives

A synthesis and study of the spatial structure of 3-acetyl-4-hydroxy-2-oxo-1,2-dihydroquinoline have been carried. 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids [1-(4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)ethylidene]hydrazides were prepared from this compound by two routes. A comparative analysis of the antitubercular properties of the synthesized compounds and of the closely structurally related N,N′-di(1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carbonyl)hydrazines has been performed. *For Communication 151 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 214–222, February, 2009.     

Water-acetic acid mediated an efficient one-pot eco-friendly synthesis of novel bis-isoxazolopyrroloquinoline derivatives

An efficient, cost-effective and environmentally benign synthesis of novel tetracyclic bis-isoxazolopyrroloquinoline derivatives has been developed via one-pot four-component reaction of 4-amino-3-methyl-5-styrylisoxazoles, dimedone, aryl glyoxal monohydrates and 5-amino-3-methylisoxazole by employing water as a reaction medium and acetic acid (AcOH) as a green promoter. The advantages of this protocol are environmentally friendly, metal-free, less reaction time, operational simplicity, high yields, broad substrate scope and easy purification. Most significant of all, this method is green.     

Highly efficient one-pot,three-component synthesis of 1, 5-benzodiazepine derivatives

A general, mild and efficient protocol for the synthesis of ethyl 4-methyl-2-（thiophen）-2,5-dihydro-1,5- benzodiazepine-3-carboxylate is achieved for first time using H3PMo12O40 in ethanol at 0 ℃ by a one- pot, three-component condensation of various thiophene aldehydes, substituted o-phenylenediamines and ethyl acetoacetate. Compared with the conventional synthesis method, this procedure has the advantages of convenient operation, excellent yields, and environmentally benign. A plausible formation mechanism has been proposed. The structure of the products is characterized by1H NMR, IR, MS and elemental analysis.     

4-Hydroxy-2-quinolones 131. Bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline

The bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline by molecular bromine is accompanied by the closure of a five membered furan ring and gives the corresponding 2-bromomethyl-3,9-dihydro-2H-furo[2,3-b]quinolin-4-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1677–1686, November, 2007.     

Fe3O4/SiO2 nanoparticles: an efficient and magnetically recoverable nanocatalyst for the one-pot multicomponent synthesis of diazepines

In this research, a new protocol for the one-pot multicomponent synthesis of diazepine derivatives using a 1,2-diamine, a linear or cyclic ketone, and an isocyanide in the presence of a catalytic amount of silica-supported iron oxide (Fe₃O₄/SiO₂) nanoparticles at ambient temperature in excellent yields is described.     

An efficient ZrCl4 catalyzed one-pot solvent free protocol for the synthesis of 4-substituted coumarins

A versatile and efficient route to 4-substituted coumarins via a Pechmann reaction using ZrCl₄ as the catalyst (10 mol %) is described. This method provides several advantages over alternative procedures such as mild, solvent-free conditions at ambient temperature, and direct isolation of the products in high yields.     

Convenient one-pot synthesis of thiobarbituro-quinoline derivatives via catalyst-free multicomponent reactions in water

A one-pot, three-component condensation reaction of 8-quinolinol, 2-thiobarbituric acid and isatins or aldehydes in water to give novel barbituroquinoline derivatives for the first time, is described. The reaction is free of catalysts and toxic solvents, operating under mild conditions and allows for ease of product isolation, making it more environmentally friendly and suitable for large-scale operations.     

A convenient and efficient one-pot method for the synthesis of novel acridine-calix[4]arene derivatives as new DNA binding agents via multicomponent reaction

A new approach is applied for the synthesis of novel acridine-calix[4]arene derivatives via a multicomponent reaction. These compounds have been characterised by ¹H NMR, ¹³C NMR and HR-MS. Our binding studies between acridine-functionalised calix[4]arenes and calf thymus DNA (CT-DNA) via fluorescence titration show that these compounds have a good affinity to CT-DNA.     

Facile,eco-friendly,one-pot protocol for the synthesis of indole-imidazole derivatives catalyzed by amino acids

An efficient, convenient green approach for the synthesis of indole-based 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by multicomponent reaction of substituted 2-arylindole-3-carbaldehydes, benzil, substituted anilines, and ammonium acetate using catalytic amino acid (glycine) in ethanol is described. Several amino acids have also been evaluated as organic catalysts for these reactions. The structures of the compounds have been established on the basis of infrared, mass, and ¹H NMR spectral data. The mild reaction conditions, inexpensive/economical reagents, and good yield show the usefulness of this approach.     

(Bromodimethyl)sulfonium bromide catalyzed efficient multicomponent one-pot synthesis of homoallylic amines

Three-component reactions of aldehydes, amines and allyltributylstannane in the presence of a catalytic amount of (bromodimethyl)sulfonium bromide have been accomplished in short reaction times to afford the corresponding homoallylic amines in excellent yields.     

Concentrated solar radiation-assisted one-pot/multicomponent synthesis of pyranopyrazole derivatives under neat condition

Research on Chemical Intermediates - Concentrated solar radiation (CSR)-assisted synthesis of pyranopyrazole derivatives under solvent and catalyst-free condition has been reported in the present...