JOURNAL OF THE IRANIAN CHEMICAL SOCIETY(JICS)
Year:2016 | Volume:13 | Issue:8|Papers Count:20

Immobilization of acidic ionic liquid, 1-methyl-3- (3-trimethoxysilylpropyl) imidazolium hydrogen sulfate on cellulose (Cell-[pmim] HSO4) as an efficient heterogenous catalyst for the simple and environmentally benign synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media at room temperature is described. The catalyst was characterized by FTIR spectroscopy and X-ray diffraction pattern. This method provides several advantages such as mild reaction conditions, environmentally friendly catalyst, good to excellent yields and simple work-up procedure.

In the present study, a new, simple, rapid, and environmentally friendly headspace-liquid phase microextraction method followed by gas chromatography–flame ionization detection has been developed for the extraction/preconcentration and determination of 1, 4-dioxane from shampoo. The developed procedure is performed in a home-made extraction vessel, connected to a glass vial containing sample and extraction solvent. In this method, an aliquot weight of shampoo is mixed with a binary mixture of n-hexane and dichloromethane (50:50, v/v) as the extractant and the target analyte is extracted during a liquid–liquid extraction procedure. Then a home-made extraction vessel containing a few microliters of a collection/extraction solvent is contacted to a glass vial containing the organic phase obtained from the previous step. By heating 1, 4-dioxane is vaporized and enriched in a mL volume of the collection/extraction solvent. Then an aliquot volume of the collected phase is injected into the separation system. The effect of several factors which may influence performance of the method, including kind and volume of the extraction solvents used in both steps, extraction temperature, extraction time, and salt addition were evaluated. Under the optimum extraction conditions, limits of detection and quantification for the target analyte were obtained 0.52 and 1.73 mg kg-1, respectively. Enrichment factor and extraction recovery were 333 and 89 %, respectively. The method precision was evaluated at a concentration of 25 mg kg-1 and relative standard deviation was less than 6.9 % for intra-day (n = 6) and inter-day (n = 4) precisions. Finally, the proposed method has been successfully applied in analysis of 1, 4-dioxane in different shampoo samples.

The key intermediate for the synthesis of (+)-Huperzine A, bicycle[3.3.1]nona-2,6-dien-9-one core, was prepared by Michael–Aldol annulation of b-ketoesters and methacrolein catalyzed by a, a-diarylprolinol silyl ether in highest 87 % ee and with up to 80 % ee in the gram-scale procedure.

HSiW-MOF, PMo-MOF, HPMo-MOF and PW-MOF were synthesized and characterized by elemental analysis, UV–Vis, FT-IR, cyclic voltammetry and XRD. These compounds were used as catalyst for the selective oxidation of alcohols by hydrogen peroxide. Within them, PW-MOF showed a higher catalytic activity compared to other catalysts in a similar reaction condition. Therefore, PW-MOF catalyst system was successfully used for the selective oxidation of the benzylic, linear and secondary alcohols to the corresponding aldehydes and ketones. Also, allylic alcohols were converted to the corresponding aldehydes with high conversion and significant selectivity. Moreover, PW-MOF was stable to leaching, behaved as true heterogeneous catalysts, easily recovered by filtration, and reused four times with the preserve of the catalytic performance.

A practically efficient, environment friendly, and solvent free microwave-assisted protocol was developed for the synthesis of pyrazole-4-carboxylates. In this connection, we synthesized five new compounds (4a-4e) via microwave irradiation of a mixture of benzophenone hydrazones and acetoacetates in the absence of solvent. Short reaction time, easy workup and quantitative yield are the striking features of our protocol.

In this paper the successful application of DABCO both as base and as ligand for efficient coupling reactions of aryl iodides and bromides with 2-hydroxybenzaldehydes in the presence of catalytic amounts of PdCl2 in water as solvent was introduced.

In the present investigation, we have developed a novel technique to prepare azines using nano-WCl6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl6/Mont. K10 under mild conditions. The nanostructures of WCl6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements.

In this study, a novel method was reported for the extraction of methamphetamine from urine samples using magnetic solid phase extraction (MSPE) technique. Magnetic nano graphene oxide (MNGO) was synthesized and applied as a new adsorbent for the extraction of methamphetamine from urine samples. The successful synthesis of MNGO was confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The main factors (the amounts of sample volume, amount of adsorbent, type and amount of extraction organic solvent, time of extraction and desorption, pH, the ionic strength of extraction medium, and agitation rate) influencing the extraction efficiency were investigated and optimized. Under optimized extraction conditions, a good linearity was observed in the range of 100-1500 ng mL-1 with the correlation coefficient of 0.9973 (r2). Limit of detection (LOD) and Limit of quantification (LOQ) were 30 and 100 ng mL-1, respectively. The inter-day and intra-day precisions were within 8.18 and 9.21 %, respectively. The inter-day and intra-day biases were -0.39 and -0.44 %, respectively. The recovery of spiked samples was 91.76 %. The method was applied for determination of methamphetamine in abused drug urine samples with the recovery of 93.47 %. It was concluded that the proposed method can be applied in forensic clinics for the determination of methamphetamine in addicted subjects.

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.

A simple and concise method catalyzed by nanocrystalline ZnZr4(PO4)6 ceramics has been reported for the synthesis of a series of trans-2-benzoyl-3-(aryl)-2H-furo[3, 2-c]chromen-4(3H)-ones using a multicomponent reaction of 2,4’-dibromoacetophenone, benzaldehydes and 4-hydroxycoumarin under microwave irradiation. This method provides several advantages including easy workup, excellent yields, short reaction times, using of microwave as clean method, recoverability of the catalyst and little catalyst loading.

Efficient epoxidation of alkenes catalyzed by tetrakis (p-aminophenyl) porphyrinato manganese (III) chloride, [Mn (TNH2PP) Cl], supported on graphene oxide nanosheets, is reported. The catalyst, [Mn (TNH2PP) Cl]@GO, was prepared by covalent attachment of amino groups of porphyrin to carboxylic acid groups of GO. This new heterogenized catalyst was characterized by ICP, FT-IR and diffuse reflectance UV–vis spectroscopies, scanning electron microscopy and transmission electron microscopy. This catalyst was applied as an efficient and reusable catalyst in the epoxidation of alkenes with NaIO4 at room temperature, in the presence of imidazole as axial ligand. The most noteworthy advantage of [Mn (TNH2PP)Cl]@GO is its high reusability in the oxidation reactions, in which the catalyst was reused several times without significant loss of its catalytic activity.

[Pd (FLU)2X2].yH2O.zCH3OH (FLU = flubendazole; X = Cl (1), y = 0, z = 0; X = Br (2), NO3(3), y = 2, z = 0; X = SCN (4), y = 2, z = 3) were synthesized as potential anticancer complexes, and their structures were elucidated using elemental analysis, TG/DTA, IR, 1H NMR, UV–vis., and conductivity measurements. FLU interacts with Pd (II) ions as a neutral unidentate ligand via the pyridine-type nitrogen of the benzimidazole ring. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were performed by DFT/B3LYP method. FLU, in comparison to its complexes, was screened for its antibacterial and cytotoxic activity. Complexes 1–4 possess strong anticancer activity with IC50 values (4.13–3.68 mg ml-1) compared with 3.57 mg ml-1 reported for cis-platin. The cytotoxicity was shown to be affected by the nature of the anion, where the sequence is 3 > 2 > 4 > 1 in case of MCF7 cell line. Structural-activity relationships suggested that EHOMO, energy gap and dipole moment were the most significant descriptors for the correlation with the antitumor activity.

A new group of 3-substituted-5H-benzo[5,6] [1, 4] thiazino[3, 2-e] [1 2, 4]triazines was designed, synthesized and evaluated as inhibitors of 15-lipoxygenase (15-LO), and the results were compared with those of standard ligand 4-methyl-2-(4-methylpiperazin-1-yl) pyrimido[4, 5-b] [1, 4] benzothiazine (4-MMPB). Among the newly designed ligands, compound 9e showed the best IC50 of 15-LO inhibition (IC50 = 38 mM). The docking calculations were performed in MOE software based on the function of force-field scoring, in order to study the interaction of these new compounds and standard ligand with 15-LO. The docking study implied that these ligands have hydrogen bond interaction with the residue of active site of 15-LO.

The purely aqueous-phase reduction of a wide range of nitro compounds to the corresponding amines has been carried out with NaBH4 in the presence of inexpensive Cu nanoparticles as catalyst. The reactions were taken place in water (80oC) within 4-15 min to give amines in high to excellent yields.

Au nanoparticles (AuNPs) are increasingly utilized as sensitive (bio) chemical probes due to their exceptional physicochemical properties and ease of functionalization. AuNPs, when functionalized with proper ligands, allow the development of highly selective colorimetric sensor. The aim of this paper was to discuss the usage of a reliable and sensitive colorimetric sensor, for sensing dissolved acetone based on the L-cysteine capped gold nanoparticles. The AuNPs were modified with L-cysteine through Au–S bonds. Acetone adsorbs on the surface of L-cysteine-AuNPs and induces the aggregation of AuNPs, due to the strong hydrogen-bonds formed between cysteine and acetone. Upon the addition of Acetone, the solution showed a color change from red to blue, which was also monitored by visible spectra. Under optimum conditions, acetone was detected at concentrations higher than 6.5 × 10-7 mol L-1, with a linear range from 1.0 × 10-6 to 6.1 × 10-5 mol L-1. The relative standard deviation for six replicates determinations of 2.0 × 10-5 mol L-1 of acetone was calculated to be 1.2 %.The selectivity was investigated by assaying some potentially interfering chemicals.

Three new zinc (II) complexes of [Zn (6-mbipy)(h2-NO3)2] (1), [Zn (6,6′-dmbipy) (h2-NO3)2] (2) and [Zn (5,5′-dmbipy) (h2–NO3) (H2O)2] (NO3).H2O (3) were prepared from the reaction of 6-methyl-2, 2′-bipyridine (6-mbipy), 6,6′-dimethyl-2, 2′-bipyridine (6, 6′-dmbipy) and 5, 5′-dimethyl-2, 2′-bipyridine (5, 5′-dmbipy) with Zn(NO3)2.4H2O in methanol, respectively. These three complexes were thoroughly characterized by elemental analysis, thermal gravimetric analysis, differential thermal analysis, infrared, UV–Vis, 1H NMR and 13C {1H} NMR spectroscopy, and their structures have all been determined by the single-crystal X-ray diffraction. The luminescence spectra of the title complexes show that the intensity of their emission bands is stronger than the bands for the free ligands.

X-ray crystal structure analysis and quantum chemical calculations based on the density functional theory (DFT) were used for structural and electronic characterizations of three 2, 3-dihydroquinazolin-4(1H)-ones (DHQZs). The occurrence of the C2-stereocenter in the heterocyclic ring causes the formations of both R- and S-enantiomers. X-ray diffraction technique indicates that these compounds exist as a racemic mixture in the crystal structure, and the enantiomers are orientated to each other via hydrogen bonding between the potential hydrogen donor (N3–H) and acceptor species (C4 = O group) in each layer under the formation of an enantio-syndio packing. Additional intermolecular and intramolecular interactions affect the orientations of the molecules adopted in the crystal packing, especially the orientation of the ring substitution. Most computational data, including the bond lengths and angles, are well in agreement with the experimental data. Dihedral angle scanning elucidates the effect of the nature and the location of the additional substituent on the aryl group at C2-position on the total energy content of the molecule.

A facile, green, and efficient method has been developed for the synthesis of biologically important pyrano [4, 3-b] pyrans in the presence of nano-cellulose-OSO3H as a new solid acid catalyst. The reaction involves the use of 4-hydroxy-6-methyl-2H-pyran-2-one, malononitrile, and aldehydes. A wide range of aldehydes is compatible in this reaction, producing excellent yields in short time. The morphology of nano-catalyst (nano-cellulose-OSO3H) was observed using a scanning electron microscopy (SEM). The cellulose-OSO3H surface was studied by the energy dispersive X-ray spectroscopy (EDX) method to find out the chemical composition. The decomposition steps and thermal stability of the catalyst were investigated by thermal analysis techniques (TGA/DTG). In addition, the vibrational spectrum analysis (FT-IR) and X-ray diffractogram (XRD) of the catalyst have been performed.

In the present study, we mainly focused on new synthesized 1,7-diazacarbazole derivatives (44 active molecules) as Chk1 inhibitors to build 3D-QSAR model. Comparative molecular field analysis (CoMFA) model with three principal components was developed. The relative contributions in building of CoMFA model were 64.41 % for steric field and 35.59 % for electrostatic field. R2 values for training and test sets of CoMFA model were 0.8724 and 0.7818, respectively, and squared correlation coefficient for leave-one-out cross-validation test (q2) was 0.6753. To improve the predictive power, a new 3D-QSAR model was developed by using radial basis function network (RBFN) and score of CoMFA interactions energy values as input variables. Scores 1, 2 and 3 were used as input variables, and a RBFN model with seven centers and spread value equal to 95 was developed to create a nonlinear 3D-QSAR model. R2 values for training and test sets were 0.9613 and 0.8564, and q2 for leave-one-out cross-validation test was 0.9258. Docking of all molecules to 3DX ligand binding site of Chk1 receptor indicated six interactions as pharmacological interactions between compounds and binding site of receptors. These pharmacological interactions were hydrogen bonding with LEU-15 and GLU-85 in main chain and four van der Waals interactions with LEU-15, VAL-23, TYR-86 and LEU-137 in side chain. CoMFA contour plots were used to design new inhibitors, and inhibitory activity of each compound was predicted by using CoMFA and RBFN models.

In this method, we have reported the catalytic ability of saccharin as a green, eco-friendly catalyst for the multi-component efficient synthesis of 3, 4-dihydropyrimidin-2-(1H)-one derivatives and 1H-pyrazolo [1,2-b]phthalazine-5,10-dione derivatives and substituted dihydro-2-oxypyrrole with excellent yields and short reaction times. This present methodology has notable benefits such as green, inexpensive and non-toxic catalyst, one-pot, environmental benign nature, solvent-free conditions, simplicity of operation with no necessity of chromatographic purification steps and eco-friendly.Graphical AbstractWe have studied the catalytic ability of saccharin as a green, economical and environmentally benign nature for the multi-component efficient synthesis of 3, 4-dihydropyrimidin-2-(1H)-ones derivatives, 1H-pyrazolo [1, 2-b]phthalazine-5, 10-dione derivatives and substituted dihydro-2-oxypyrrole with excellent yields and short reaction times. Green catalyst, mild, non-toxic, inexpensive, simple operational procedures, one-pot, high catalytic activity, eco-friendly, easily separated from the reaction mixture with no column chromatographic for the one-pot multi-component synthesis of these compounds are the most important advantages of this procedure.