Publications by authors named "Ali Khalafi-Nezhad"

A one-pot multicomponent reaction of a variety of benzaldehydes, dimedone, and 1-1,2,4-triazol-3-amine for the efficient synthesis of quinazolinone derivatives under green conditions is reported. It was proved that MIL-101(Cr) could carry out successfully this multicomponent strategy to afford target products in high yields. The scope and limitation of this catalytic system concerning the aldehyde substrates were explored.

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In this study the catalytic application of a heterogeneous Pd-catalyst system based on metal organic framework [Pd-NHC-MIL-101(Cr)] was investigated in the synthesis of distyrylbenzene derivatives using the Heck reaction. The Pd-NHC-MIL-101(Cr) catalyst showed high efficiency in the synthesis of these π-conjugated materials and products were obtained in high yields with low Pd-contamination based on ICP analysis. The photophysical behaviors for some of the synthesized distyrylbenzene derivatives were evaluated.

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Unlabelled: Diabetes mellitus is a metabolic disorder characterized by high blood glucose levels and instability in carbohydrate metabolism. For treating diabetes, one important therapeutic approach is reducing the postprandial hyperglycemia which can be managed by delaying the absorption of glucose through inhibition of the carbohydrate-hydrolyzing enzymes, α-amylase (α-Amy) and α-glucosidase (α-Gls) in the digestive tract. In this work, a new class of curcumin derivatives incorporating pyrano[2,3-d]pyrimidine heterocycles was synthesized using a multicomponent reaction between curcumin, aldehydes, and barbituric acid.

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In this study, a new class of curcumin derivatives was synthesized using a multicomponent reaction containing curcumin, aldehydes, and malononitrile. This new protocol afforded a novel class of 4H-pyran heterocycles incorporating curcumin moiety. The products were obtained in the presence of p-toluenesulfonic acid (PTSA) as a catalyst in ethanol solvent in good to excellent yields.

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Spired by the chemical structure of Cilostazol, a selective phosphodiesterase 3A (PDE3A) inhibitor, several novel hybrid compounds of nucleobases (uracil, 6-azauracil, 2-thiuracil, adenine, guanine, theophylline and theobromine) and tetrazole were designed and successfully synthesized and their inhibitory effects on PDE3A as well as their cytotoxicity on HeLa and MCF-7 cancerous cell lines were studied. Obtained results show the linear correlation between the inhibitory effect of synthesized compounds and their cytotoxicity. In some cases, the PDE3A inhibitory effects of synthesized compounds are higher than the Cilostazol.

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A multicomponent reaction containing curcumin, aldehydes, malononitrile and amine was developed for the one-pot synthesis of a novel library of 4H-pyran and 1,4-dihyropyridin heterocycles incorporating curcumin moiety. The products were obtained in the presence of p-toluenesulfonic acid as catalyst in ethanol as solvent in good to excellent yields.

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New quinazoline derivatives were prepared by one pot reaction of anthranilic acid, acetic anhydride and primary amines, under ultrasonic irradiation. As a result, Ultrasonic irradiation has led to affordable, clean synthesis of a variety of target compounds in much higher yields, than traditional methods. This method has numerous advantages: such as higher yields, shorter reactions time, and easier work-up.

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In this study, a multicomponent reaction involving carbohydrates, β-dicarbonyl compounds, and malononitrile was disclosed to synthesize a new class of polyhydroxy compounds incorporating pyrano[2,3-]pyrimidine, pyrido[2,3-]pyrimidine and chromene heterocycles under mild conditions. For the synthesis of this class of compounds, glucose, galactose, arabinose, maltose, and lactose were used as aldehyde component in the reaction with barbituric acid and malononitrile to produce pyrano[2,3-]pyrimidine derivatives. By use of 1,3-cyclohexanedione instead of barbituric acid, chromene derivatives incorporating carbohydrate moieties were obtained.

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A metal-organic framework [MIL-101(Cr)] was used as an efficient heterogeneous catalyst in the synthesis of benzoazoles (benzimidazole, benzothiazole, and benzoxazole), and quantitative conversion of products were obtained under optimized reaction conditions. The catalyst could be simply extracted from the reaction mixture, providing an efficient and clean synthetic methodology for the synthesis of benzoazoles. The MIL-101(Cr) catalyst could be reused without a remarkable decrease in its catalytic efficiency.

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In the current study, glycerol was successfully employed as a nonvolatile, non-toxic, non-flammable, biodegradable, very cheap, easily accessible, and efficient reaction medium for the microwave-enhanced diastereoselective synthesis of 2-(N-carbamoylacetamide)-substituted 2,3-dihydrothiophenes via a catalyst-free one-pot four-component reaction. A versatile range of starting materials were used, and diverse products were obtained in good to excellent yields and very short reaction times. Moreover, the reaction medium was recovered and reused several times without any loss of the efficiency.

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In this study, amino acids and peptides were used as reactants in a Hantzsch multicomponent reaction in order to synthesize new structurally diverse molecules containing these synthons. As well, an applicable strategy for modification of these natural molecules with heterocycle backbones such as pyrimidine, xanthene and acridine is introduced. Using this method, a set of new amino acid- and peptide-functionalized heterocycles were synthesized in good to excellent yields under mild conditions.

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A novel and highly efficient method for N-fluoroalkylation of amines using 2,4,6-tris(fluoroalkoxy)-1,3,5-triazines was developed. This simple approach allowed the N-fluoroalkylation of amines under fast, mild and efficient reaction conditions, without using a transition metal as a catalyst.

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We report the first Barton radical decarboxylation of unprotected bile acids via in situ irradiation of their thiohydroxamic esters in the presence of citraconic anhydride and citracoimide, leading to the synthesis a series of steroidal maleic anhydrides and maleimides as novel hybrid bile acids. The cytotoxic activities were evaluated on C6 rat glioma cells.

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In this study, L-cysteine was chemically grafted to magnetic nanoparticles in order to prepare a reusable magnetic material incorporating an amino acid moiety. For this purpose, silica-coated magnetic nanoparticles (Fe3O4@SiO2) were reacted with trimethoxy(vinyl)silane to produce vinyl-functionalized magnetic nanoparticles (VMNP). Reaction of a VMNP substrate with L-cysteine in the presence of azobisisobutyronitrile (AIBN) resulted in the production of L-cysteine-functionalized magnetic nanoparticles (LCMNP).

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In this study a novel series of poly-hydroxyl functionalized acridine derivatives (L1-L9) was synthesized and their inhibitory activities against α-Glucosidase (α-Gls) and α-Amylase (α-Amy) were evaluated, spectroscopically. The synthetic compounds consist of three different substructures, including a 4-(4-aminophenoxy) phenyl group (R3), an acridine moiety (R2) and a poly-hydroxy chain (R1). The results indicate that among the synthetic compounds, L5 with a chromeno[3',4':5,6]pyrido[2,3-d]pyrimidine moiety demonstrates the highest inhibitory activity against both yeast and rat α-Gls enzymes.

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Curcumin (bis-α,β-unsaturated β-diketone), the chief constituent of turmeric plant (Curcuma longa), plays significant role in prevention of various diseases including diabetes. The research objective in the current study was to synthesize novel anti-diabetic curcumin derivatives with inhibitory properties against α-amylase (α-Amy) and α-glucosidase (α-Gls), as these two carbohydrate-hydrolysing enzymes are known to be important molecular targets for attenuation of postprandial hyperglycemia. The curcumin-based pyrano[2,3-d]pyrimidine derivatives were synthesized in the presence of curcumin, barbituric acids and aldehydes, using a multi-component reaction (MCR).

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In this study a multicomponent reaction involving carbohydrate derivatives as the main component in order to prepare a new library of polyhydroxy compounds incorporating pyrimidine-fused heterocycles (PFHs) is introduced. A set of polyhydroxy functionalized PFHs were synthesized using multicomponent reactions of sugar (glucose, galactose, arabinose and lactose), barbituric acid and amines. Also, the three-component condensation reaction between D-glucosamine, aldehyde, and barbituric acid efficiently provided polyhydroxy substituted PFH derivatives in a one-pot reaction under mild and green conditions.

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An example of the application of the Strecker reaction in the synthesis of a new class of α-aminonitriles with benzimidazole and theophylline backbones has been developed. For the synthesis of these compounds, first 4-hydroxybenzaldehyde was reacted with 1,3- and 1,5-dibromides/epibromohydrin to produce the corresponding bromo-substituted aldehydes. Then, benzimidazole/theophylline was reacted with the latter to generate the related benzimidazolic/theophyllinic aldehydes.

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Bovine milk β-lactoglobulin (β-LG) demonstrates significant resistance against both gastric- and simulated duodenal digestions. Therefore, it seems a realistic protein candidate for safe delivery and protection of particularly pH sensitive drugs in stomach. Recently, pyrimidine fused heterocycles (PFHs) revealed inhibitory properties against α-glucosidase (α-Gls) which is an important target enzyme for those drugs playing significant role in treatment of type-II diabetes and HIV/AIDS infection.

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The synthesis of a set of pyrimidine-fused derivatives (L1-L8), resulting from the incorporation of different fragments on the pyrimidine-fused heterocycle (PFH) of the earlier reported α-glucosidase (α-Gls) inhibitor (C1-C5), allowed the discovery of new ligands with modest and selective inhibitory activity. The PFH core (substructure 2) was proved to play a significant role in their inhibitory properties. Additionally, the substituent on substructures 1 and 3 of the heterocyclic ring was demonstrated to be important in the enzyme inhibitory action of the pyrimidine-fused derivatives.

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Magnetic, supported, acidic ionic liquid was synthesized and identified as an efficient catalyst for the one-pot synthesis of novel spirooxindole derivatives at mild conditions and in good yields. Three component reaction of wide variety of substituted isatins, 1,3-dimethyl-2-amino uracil, and barbituric acid, thiobarbituric acid, and dimedon as 1,3-dicarbonyl compounds gives the target compounds. Operational simplicity, low cost, high yields, environmental friendliness, wide applicability and reusability and easy recovery of the catalyst using an external magnet are the key features of this methodology.

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The needs for diverse inhibitors of α-glucosidase (α-Gls) encouraged us to synthesize five different poly-hydroxy functionalized pyrimidine-fused heterocyclic (PHPFH) molecules, having either aliphatic or aromatic side chains (C1-C5) and their inhibitory activities were examined spectroscopically against yeast and mouse intestinal α-Gls. The results revealed that aromatic substitution of the synthetic compounds has significant impact on their inhibitory properties. Moreover C3 with the substituted moiety as 4-(4-aminophenylsulfonyl) phenyl (4-APSP) revealed strong inhibitory activity with non-competitive and competitive inhibition modes against yeast and mouse α-Gls, respectively.

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A simple, clean and highly efficient method for the preparation of polyhydroxyl aromatic compounds is described from the reaction of 2,6-bis(methylol)phenols and different substituted phenols in the presence of silica sulfuric acid (SSA) as a heterogeneous catalyst. SSA afforded the clean synthesis of target compounds in much higher yields than traditional catalysts. The established method is also suitable for the synthesis of phloroglucinol derivatives (Phloroglucides) and other polyhydric phenols.

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The syntheses of novel hydrazono acyclic nucleosides similar to miconazole scaffolds are described. In this series of acyclic nucleosides, pyrimidine as well as purine and other azole derivatives replaced the imidazole function in miconazole and the ether group was replaced with a hydrazone moiety using phenylhydrazine. To interpret the dominant formation of (E)-hydrazone derivatives rather than (Z)-isomers, PM3 semiempirical quantum mechanic calculations were carried out which indicated that the (E)-isomers had the lower heats of formation.

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