Neat synthesis of octahydroxanthene-1,8-diones,catalyzed by silicotungstic acid as an efficient reusable inorganic catalyst

In this article, the first use of silicotungstic acid (H₄SiW₁₂O₄₀) as a catalyst for the synthesis of octahydroxanthene-1,8-diones by the reaction of 5,5-dimethylcyclohexane-1,3-dione (dimedone) with various aldehydes under thermal solvent-free conditions is described. The obtained results showed that the catalyst has a high catalytic activity, and the desired products were obtained in high yields. Moreover, the catalyst was found to be reusable, and a considerable catalytic activity still could be achieved after the fifth run. Easy work-up and avoidance of using harmful organic solvents are the other advantages of this simple procedure.     

Nanoparticles tungstophosphoric acid supported on polyamic acid: catalytic synthesis of 1,8-dioxo-decahydroacridines and bulky bis(1,8-dioxo-decahydroacridine)s

Tungstophosphoric acid nanoparticles supported on polyamic acid (TPA NPs/PAA) was prepared and employed as a catalyst for the facile selective synthesis of 1,8-dioxo-decahydroacridines and some bulky bis(1,8-dioxo-decahydroacridine)s via one-pot condensation of 5,5-dimethyl-1,3-cyclohexanedione and various aldehydes with aniline or ammonium acetate in ethanol–water solution. This catalyst was characterized by FT-IR, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), energy-dispersive X-ray analysis (EDAX), and inductively coupled plasma optical emission spectrometry (ICP-OES). The catalyst showed high thermal stability and good reusability. The products were isolated in high purity and the catalyst was easily separated in a simple workup and recycled several times without noticeable loss of activity under the described reaction conditions. The reaction is characterized by short reaction time, high efficiency, and mild reaction conditions.     

Nanorod vanadatesulfuric acid (VSA NRs)-catalyzed green synthesis of hexahydroacridine-1,8-diones in solvent-free conditions

Nanorod vanadatesulfuric acid (VSA NRs), as a novel, recyclable and eco-benign catalyst, was used for an efficient synthesis of hexahydroacridine-1,8-diones using 1,3-cyclohexanedione derivatives, aldehydes and ammonium acetate or aniline under solvent-free conditions. VSA was prepared by the reaction of high-purity chlorosulfonic acid and sodium metavanadate. The present method offers some advantages over conventional ones, such as simple procedure and work-up, short reaction times, high yields, stability and reusability of the catalyst and simple purification of the products. Also, some greenness aspects of this method were investigated and compared with data from previous reports.     

Polyethylene glycol-mediated synthesis of decahydroacridine-1,8-diones catalyzed by ceric ammonium nitrate

Polyethylene glycol was found to be an inexpensive non-toxic and effective medium for one pot synthesis of high yields of decahydroacridine-1,8-diones in the presence of ceric ammonium nitrate as the catalyst. Moreover, the solvent can be recovered and reused.     

Synthesis of partially hydrogenated pyrazolo[3,4-b]quinolinones by condensation of 3-amino-5-methylpyrazole with aromatic aldehydes and dimedone

Cyclocondensation of 3-amino-5-methylpyrazole with 2-arylmethylidene-5,5-dimethylcyclohexane-1,3-diones or 9-aryl-3,3,6,6-tetramethyl-2,3,4,5,6,7,8,9-octahydro-1H-xanthene-1,8-diones, as well as with synthetic precursors of the latter (para-substituted benzaldehydes and dimedone), in dimethylformamide or methanol gives the corresponding 4-aryl-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-ones. The structure of 4-(4-methoxyphenyl)-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-one was proved by the X-ray diffraction data.     

Ceric ammonium nitrate (CAN) catalyzed synthesis of N-substituted decahydroacridine-1,8-diones in PEG

Polyethylene glycol (PEG) was found to be an inexpensive non-toxic and effective medium for the one-pot synthesis of N-substituted decahydroacridine-1,8-diones in the presence of ceric ammonium nitrate (CAN) as the catalyst in high yields. Also, the solvent system can be recovered and reused; making this protocol economically and potentially viable.     

Synthesis and transformations of new 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione derivatives

Reactions of cyclohexane-1,3-diones with amines and aldehydes led to the formation of 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones containing alkylaryl, aryl, and hydroxy substituents in position 10. Transformations of 10-hydroxy-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones under oxidation with nitrous acid, reduction with zinc powder, as well as on heating in aprotic solvents and acetic, phosphoric, and polyphosphoric acids, were studied. NMR spectra of 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-diones having different substituents in positions 9 and 10 were analyzed.     

Synthesis,characterization and heterogeneous catalytic application of a nickel(II) Schiff base complex immobilized on MWCNTs for the Hantzsch four-component condensation

A nickel(II) Schiff base complex immobilized on multi-wall carbon nanotubes (MWCNTs) surface as a highly efficient heterogeneous catalyst was synthesized and characterized by IR, X-ray diffraction patterns, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma, elemental analysis, and thermal gravimetric analysis. Then a facile and environmentally benign procedure was developed for synthesis of polyhydroquinoline derivatives via Hantzsch one-pot condensation reaction of aromatic aldehydes, 1,3-diones, ethyl acetoacetate, and ammonium acetate in the presence of above synthesized catalyst under solvent-free conditions. This protocol has the advantages of stability, easy availability, recyclability and eco-friendly nature of catalyst, simple experimental and work-up procedure, and also high to excellent yields. Considering the solvent-free condition and also temperature, time, and yield of the model reaction, the nanocatalyst reported here is among the best catalysts reported so far for synthesis of polyhydroquinolines.     

Baker’s yeast: An efficient,green, and reusable biocatalyst for the one-pot synthesis of biologically important N-substituted decahydroacridine-1,8-dione derivatives

A green approach for one-pot three-component synthesis of N-substituted decahydroacridine-1,8-diones is offered for the first time using baker’s yeast (Saccharomyces cerevisiae) as a biocatalyst under ultrasonication. Due to growing safety and environmental concerns, enzymatic methods were constantly investigated as an attractive alternative to toxic and nonspecific chemical approaches. This method is relatively simple, efficient, inexpensive, and environment-friendly. The catalyst was recovered and reused and also the recyclability of baker’s yeast resulted in excellent yields of products without loss of any catalytic activity.     

Three-Component One-Pot Synthesis of Polyhydroacrodine Derivatives in Aqueous Media

9,10-Diaryldecahydroacridine-1,8-diones were synthesized by a three-component reaction of aromatic aldehydes, aromatic amines, and 5,5-dimethyl-1,3-cyclohexanedione using sodium 1-dodecanesulfonic (SDS) as the catalyst in aqueous media. The key intermediates before the cyclization step were obtained and characterized. The structures of all the products were determined by IR and ¹H NMR spectra and further confirmed by single-crystal x-ray diffraction analysis.     

A novel method to anchor methanesulfonic acid in silica matrix

Methanesulfonic acid (MSA) was successfully immobilized in silica, leading to a novel and environmentally friendly solid acid catalyst SMSA. The most important feature of SMSA is that anhydrous formic acid is used to hydrolysis of tetraethylorthosilicate (TEOS). No water was added in the whole preparation. Therefore, MSA could be anchored in silica matrix more effectively instead of being dissolved in water. This new organic/inorganic hybrid catalyst was characterized by powder X-ray diffraction (XRD), energy dispersive spectrum (EDS), N₂ adsorption-desorption analyzer, thermogravimetric analysis (TGA-DSC) and pyridine-FTIR. The catalytic activity was tested by alkylation of olefins and aromatics. High concentration acid sites, both Lewis and Brønsted, abundant porosity and large surface area enabled the highest activity for SMSA, among MCM-22, ZSM-5 and industrial acidity clay.     

Catalytic synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) and 3,3,6,6-tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-diones

Condensation of substituted benzaldehydes of vanillin series with dimedone in methanol solution in the presence of catalytic quantities of triethylamine afforded 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones. By catalytic cyclization of the latter in boiling benzene in the presence of sulfo cation exchanger FIBAN K-1 as catalyst 3,3,6,6-trimethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-diones were synthesized.     

Transformations of sym-octahydroxanthene-1,8-diones and 1,8-dioxo-sym-octahydroxanthylium salts in recyclization under the influence of amines

The chemical behavior of 9-R-sym-octahydroxanthene-1,8-diones and salts based on them in recyclization reactions under the influence of amines was studied. The effect of the basicity of the amines on the direction of recyclization was established. A method is proposed for the single-stage synthesis of sym-octahydroacridine-1.8-dione oximes based on 1,8-dioxo-sym-octahydroxanthenes. Conditions were worked out for the oxidation of sym-octahydroxanthene-1,8-diones and N-R-decahydroacridinediones to the corresponding salts. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 32–38, January, 2006.     

Cyclocondensation of 2-Aminobenzimidazole with Dimedone and Its Arylidene Derivatives

The reactions of 2-aminobenzimidazole with substituted benzaldehydes and dimedone, 2-arylidene derivatives of dimedone, 9-arylhexahydro-1H-xanthene-1,8(2H)-diones and also with dimedone and DMF have been studied. The direction of formation of the pyrimidine ring has been established and discussed. An X-ray structural investigation of 2,2-dimethyl-2,3-dihydrobenzimidazo[1,2-a]quinazolin-4(1H)-one has been carried out.     

Characteristics of the Dissociative Ionization of 9-Aryl(hetaryl)-3,3,6,6-tetramethyldecahydroacridine-1,8-diones under the Influence of Electron Impact

The mass spectra of 9-aryl(hetaryl)-3,3,6,6-tetramethyldecahydroacridine-1,8-diones have been studied and the basic directions of their dissociative ionization under the influence of electron impact have been elucidated. It has been shown that the decomposition pathways of decahydroacridine-1,8-diones depend on the nature of the substituents at position 10 and is connected with the preferential formation of a pyridinium structure with subsequent retrodiene decomposition of the molecules.     

Condensed isoquinolines 23. Reaction of <Emphasis Type="Italic">o</Emphasis>-bromomethylphenyl-acetonitrile with anthranilic acids: Synthesis of 6H, 12H,17H-dibenzo[3,4:6,7][1,8]-naphthyridino[1,8-<Emphasis Type="Italic">ab</Emphasis>]quinazoline-6,17-diones

The direction of the reaction of anthranilic acids with o-bromomethylphenylacetonitrile upon fusion depends on the temperature and nature of the substituent in the anthranilic acid. The reaction may lead to three types of products: Derivatives of 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones below 150°C and to 6,11-dihydro-13H-isoquino[3,2-b]quinazolin-13-one or derivatives of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones above 150°C depending on the nature of the substituent in the anthranilic acid. A study was carried out on the mechanism for the formation of 6H,12H,17H-dibenzo[3,4:6,7][1,8]naphthyridino[1,8-ab]quinazoline-6,17-diones, which permitted the preparation of 6-(4-methylphenyl)-6,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1059–1067, July, 2007.     

绿色可磁性分离二氧化硅包裹镍铁尖晶石负载硫酸氢铁纳米粒子催化剂用于合成1,8-二氧十氢吖啶合成Amir Khojastehnezhad,Mohammad Rahimizadeh,简

A new magnetically separable catalyst consisting of ferric hydrogen sulfate supported on silica-coated nickel ferrite nanoparticles was prepared. The synthesized catalyst was characterized using vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. This new magnetic catalyst was shown to be an efficient heterogeneous catalyst for the synthesis of 1,8-dioxodecahydroacridines under solvent-free conditions. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.     

Heterogeneous SO3H@Fe3O4 magnetic nanocatalyst as an efficient and reusable medium for the synthesis of 3,3′-(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-methane,and 1,8-dioxo-octahydroxanthene derivatives

This work aimed to synthesize a new heterogeneous catalyst (SO₃H@Fe₃O₄ magnetic nanoparticles) and the study of its catalytic behavior in synthesizing 3,3′-(arylmethylene)-bis-(4-hydroxycoumarin), bis-(indolyl)-methane, and 1,8-dioxo-octahydroxanthene derivatives. The characterization of obtained material has been performed by means of Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, vibrating sample magnetometer, and transmission electron microscopy. The main properties of this new methodology, compared to earlier ones, are the short times of reaction, mild reaction conditions, simple recovery of the catalyst by permanent magnetic field, excellent yields, and reusability of the catalyst for a minimum of six runs.     

Application of potassium-modified carbon nitride as a highly efficient recyclable catalyst for synthesis of 4H-chromene derivatives

A potassium-doped carbon nitride (K-CN) was prepared by a simple thermal polymerization method. The prepared K-CN was characterized by Fourier infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The obtained K-CN exhibited excellent catalytic activity for synthesis of 4H-chromene derivatives via one-pot three-component reaction of salicylaldehyde, cyclohexane-1,3-diones and 4-hydroxycoumarin in water/ethyl lactate at room temperature. The reported method shows significant advantages, such as high yield, mild and clean reaction conditions, the use of recyclable catalyst and ethyl lactate/water as an environmentally friendly solvent, multi-component reaction at room temperature, no chromatographic separation and suitable for large-scale synthesis.

     

Nano titania-supported sulfonic acid (n-TSA) as an efficient,inexpensive, and reusable catalyst for one-pot synthesis of 1, 8-dioxo-octahydroxanthene and tetrahydrobenzo[<Emphasis Type="Italic">b</Emphasis>]pyran derivatives

This paper explains how with the help of nano titania-supported sulfonic acid (n-TSA), new 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives can be produced. To do this, at first n-TSA, which is relatively cheap, easy separable and reusable was made. Next, using this nano catalyst,1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives were synthesized from di-ketones and various aromatic aldehydes/or malononitrile without using solvent. Appropriate one-pot operation using different aromatic aldehydes with both electron donating and withdrawing groups have resulted in the best yields. Reusability of the nano catalyst, environmental friendliness, reduced reaction time, non-toxic reaction medium and catalyst high activity are substantial advantages of this work. Nowadays, it is really important that the catalyst can be recovered easily and reused five times while maintaining catalytic activity.