Search

In this research we investigated the preparation of new (5Z, 8Z)-7H-pyrido[2,3-d]azepine derivatives in high yields via multicomponent reaction of isatins, alkyl bromides, activated acetylenic compounds and ammonium acetate using ionic liquid 1-octhyl-3-methyl imidazolium bromide ([OMIM]Br) as a stabilizer and soft template at room temperature in the presence of Fe3O4/TiO2/Carbon nanotubes magnetic nanocomposites as a reusable and effective nanocatalyst that are synthesized using ionic liquid [OMIM]Br as a stabilizer, soft template, green media and moderate base. Because of having a NH group in the synthesized pyridine derivatives, we investigate antioxidant property of some synthesized compounds by diphenyl-picrylhydrazine (DPPH) radical trapping and power of ferric reduction experiment. Short time of reaction, high yields of product, easy separation of catalyst and products are some advantages of this procedure.

In this research, new derivatives of oxazolopyrazoloazepines were synthesized in high yields using multicomponent reaction of anilines, oxalylchloride, alkyl bromides, activated acetylenic compounds, hydrazine and ethyl bromopyruvate in the presence of Ag/Fe

Background The various extracts of Trifolium resupinatum (Persian clover) sprout was obtained by using different solvents and microwave assisted extraction in the present study. Then, the bifunctionalized nanoliposomes were prepared and added to soybean oil for evaluating their effect on deferring the oxidation process. Methods The total phenol and antioxidant activity of the extracts was determined by using the free radical scavenging assay. Then, various nanoliposomal structures of the methanolic extract of Persian clover sprout (PCSE) were prepared by using six several formulations containing different ratios of soybean oil, lecithin and the extract. Afterward, the most stable nanoliposome was bifunctionalized by using WPC and pectin (PCSEN-W and PCSEN-WP, respectively). The size and zeta potential of nanoparticles were measured. Furthermore, in order to evaluate the effects of PCSE, PCSEN, PCSEN-W and PCSEN-WP at 100–300 ppm concentrations in deferring the oxidation process of soybean oil, the heat treatment tests were applied (PV and TBA) at 63 °C within a 20-day period. Results The methanolic extract had the highest level of total phenol and antioxidant activity. The results of creaming index and microencapsulation efficiency were exhibited that formulation containing 30% oil, 5% lecithin and 2% the extract was led to the production of the most stable nanoliposomal structure (PCSEN). The size of nanoparticles was in the range of 282.5–491.2 nm. Zeta potential of the samples was obtained in the range between − 56.9 and − 36.3 mV. Polydispersity index of them was ranged from 0.424 to 0.541. The results were confirmed the existence of stable nanoliposomal systems. The results of the PV and TBA values of the extracts in free and nanoliposomal forms were shown that the nanoliposomal forms had very good antioxidant activity against the oxidation process in soybean oil.

In this research we investigated the preparation of new (5Z, 8Z)-7H-pyrido[2,3-d]azepine derivatives in high yields via multicomponent reaction of isatins, alkyl bromides, activated acetylenic compounds and ammonium acetate using ionic liquid 1-octhyl-3-methyl imidazolium bromide ([OMIM]Br) as a stabilizer and soft template at room temperature in the presence of Fe

A series of novel 3-hydroxyflavones were designed and synthesized under efficient and green one-pot three-component aldol condensation/intramolecular cyclization reaction of 1-[6-hydroxy-2-(prop-1-en-2-yl)-1-benzofuran-5-yl]ethanone, substituted benzaldehyde, and hydrogen peroxide in the presence of potassium fluoride /clinoptilolite nanocatalyst in water at room temperature.

This study has evaluated the effects of different concentrations of the water and ethanolic extracts of Iranian propolis (WEP and EEP) on the microbiological and sensory parameters of minced common carp meat that was stored at 4°C for 9 days. The chemical compounds of the extracts were identified by gas chromatography–mass spectroscopy (GC-MS) analysis. The results revealed that WEP and EEP extracts were efficient against the spoilage microorganisms, including total plate counts (TPCs), psychrotrophic populations (PTCs), lactic acid bacteria (LAB), and even Staphylococcus aureus. There was a significant difference in the bacteria growth between samples treated with WEP or EEP and the control sample during storage. Inhibitory effects were, respectively, 7% EEP > 5% EEP > 3% EEP > 7% WEP > 5% WEP > 3% WEP. In all treatments, PTC counts were higher than 7 log CFU/g after 6 days as well as TPC, LAB, and S. aureus populations after 9 days. Overall, the results show that EEP and WEP have good antimicrob...

A mild and selective method for the oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones with N-ethylbenzylammonium fluorochromate (VI), EBAFC, is reported. Stability, reaction rate, ease of work-up and efficiency of the EBAFC are considerably increased upon its adsorption on silica gel. The N-ethylbenzylammonium fluorochromate (VI) adsorbed on silica gel is inert to aldehydes, ketones, oximes, thiols, sulfides, phenols, pyrans, trimethylsilanes, malonates and thioacetamides.

Background The various extracts of Trifolium resupinatum (Persian clover) sprout was obtained by using different solvents and microwave assisted extraction in the present study. Then, the bifunctionalized nanoliposomes were prepared and added to soybean oil for evaluating their effect on deferring the oxidation process. Methods The total phenol and antioxidant activity of the extracts was determined by using the free radical scavenging assay. Then, various nanoliposomal structures of the methanolic extract of Persian clover sprout (PCSE) were prepared by using six several formulations containing different ratios of soybean oil, lecithin and the extract. Afterward, the most stable nanoliposome was bifunctionalized by using WPC and pectin (PCSEN-W and PCSEN-WP, respectively). The size and zeta potential of nanoparticles were measured. Furthermore, in order to evaluate the effects of PCSE, PCSEN, PCSEN-W and PCSEN-WP at 100–300 ppm concentrations in deferring the oxidation process of soybean oil, the heat treatment tests were applied (PV and TBA) at 63 °C within a 20-day period. Results The methanolic extract had the highest level of total phenol and antioxidant activity. The results of creaming index and microencapsulation efficiency were exhibited that formulation containing 30% oil, 5% lecithin and 2% the extract was led to the production of the most stable nanoliposomal structure (PCSEN). The size of nanoparticles was in the range of 282.5–491.2 nm. Zeta potential of the samples was obtained in the range between − 56.9 and − 36.3 mV. Polydispersity index of them was ranged from 0.424 to 0.541. The results were confirmed the existence of stable nanoliposomal systems. The results of the PV and TBA values of the extracts in free and nanoliposomal forms were shown that the nanoliposomal forms had very good antioxidant activity against the oxidation process in soybean oil.

(E)-3-X-Indoline-2-thione derivatives (X = phenyl, furan-2-yl, 1H-pyrrole-2-yl, and thiophene-2-yl, I– IV , respectively) are considered as potent and selective inhibitors against different receptor tyrosine kinases. A particularly interesting issue for these biologically active compounds is how their stability is affected by solvation. Here we have tackled this issue using the self-consistent reaction field theory for I– IV , in the gas phase as well as solution including: toluene, CH2Cl2 , MeOH, and H2O. The highest observed total free energy difference between liquid (l) and gas (g) phase (∆E l–g) relates to structure III in water, whereas the lowest ∆E l–g is associated with II in toluene. Thus, III is the most solvent sensitive and enjoys maximum stabilization in water. On the other extreme, II is the least solvent sensitive and its stability is least affected by solvation in toluene. Moreover, stability of each solute (I– IV ) depends on the dielectric constant of the solvent and the possibility of the hydrogen bonding. In going from gas phase to different solvents, considerable changes of nucleophilicity as well as electrophilicity occur for scrutinized structures. The six- and five-membered rings in indoline skeleton for all species show aromatic and nonaromatic property, respectively. Finally, the substituent rings appear the most aromatic property. These phenomena are confirmed by the succeeding geometrical parameters.

A Silicon Photomultiplier (SiPM) array (ArraySM-4p9) from the SensL Inc. has been evaluated in this study. The current-voltage (I-V) characteristics of individual SiPM pixels were measured. Then the energy spectral performances of this SiPM array were evaluated with different scintillator samples as compared with a conventional PMT of Hamamatsu 878. The used scintillator samples include GAGG: Ce (3 × 3 × 6 mm 3 ), CsI (TI) (3 × 3 × 6 mm 3 ), and LYSO (2 × 2 × 5 mm 3 ). The energy spectra of these scintillator samples with a SiPM pixel were measured using gamma-ray sources of 57Co (122 keV), 22Na (511 keV) and 137Cs (662 keV) and were compared with the conventional PMT. The measured I-V curves of this SiPM device have shown good performance uniformity over the 4 × 4 SiPM array units. The channel-to-channel variations of the 16 SiPM pixels in the breakdown voltages, gains and dark currents are very consistent and stable. Gamma spectroscopy using 57Co, 22Na and 137Cs sources shows that this SiPM device has well comparable spectral performance as the conventional PMT. The SiPM with CsI (Tl) and GAGG: Ce crystals using 57 Co source show signif- icant better energy resolutions than the conventional photomultiplier tube (PMT) for the low energy gamma-ray detections. Finally, the newly available SiPMs show very good properties and are well suited with most common used scintillation crystals for gamma-ray detections in a broad energy range. The SiPM has a great promise to replace the conventional PMT.

Three- component reaction of 4-hydroxy-2H-pyran-2-one, aldehydes, and malononitrile or ethyl cyanoacetate in the presence of ZnO nanoparticles as the catalyst is described as an efficient and green synthetic method for obtaining of pyrano[4,3-b]pyran derivatives in excellent yield. These reactions were also tested with 2'-hydroxyacetophenone under similar conditions and produced chromene derivatives.

Phenolic compounds from Cressa cretica leaves were extracted using different solvents (water and ethanol 70%) during 3–24 h by immersion method and were determined according to the Folin–Ciocalteu method. The antioxidant activities of the extracts were investigated by 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) radical scavenging, ferric reduction activity potential and total antioxidant capacity assays compared with synthetic antioxidant namely BHT. The results were shown that the most total phenol content was outcome of the ethanolic extract after 18 h (68.512 ± 0.36 mg gallic acid/g dry extract) extraction. The results of different assays for determination of antioxidant potential of the extracts as well as their EC50 values were indicated antioxidant activities in order: BHT>ethanolic extract>aqueous extract. Also, the antioxidant activities were enhanced with increasing of the extracts and BHT concentrations. The results of Peroxide value (PV) and Thiobarbituric acid (TBA) tests were revealed that the ethanolic extract with various concentrations (200–1000 ppm) were suppressed the oxidation of soybean oil. The highest oxidation inhibitor was belonged to 1000 ppm concentration of the ethanolic extract so that can be good alternative for BHT.

Phenolic compounds from Cressa cretica leaves were extracted using different solvents (water and ethanol 70%) during 3–24 h by immersion method and were determined according to the Folin–Ciocalteu method. The antioxidant activities of the extracts were investigated by 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) radical scavenging, ferric reduction activity potential and total antioxidant capacity assays compared with synthetic antioxidant namely BHT. The results were shown that the most total phenol content was outcome of the ethanolic extract after 18 h (68.512 ± 0.36 mg gallic acid/g dry extract) extraction. The results of different assays for determination of antioxidant potential of the extracts as well as their EC50 values were indicated antioxidant activities in order: BHT>ethanolic extract>aqueous extract. Also, the antioxidant activities were enhanced with increasing of the extracts and BHT concentrations. The results of Peroxide value (PV) and Thiobarbituric acid (TBA) tests were revealed that the ethanolic extract with various concentrations (200–1000 ppm) were suppressed the oxidation of soybean oil. The highest oxidation inhibitor was belonged to 1000 ppm concentration of the ethanolic extract so that can be good alternative for BHT.

Minimum-energy and transition-state geometries of 4-oxobuta-1,3-diene-1-thione, buta-1,3-diene-1,4-dithione, 4-selenoxobuta-1,3-diene-1-thione, 4-selenoxobuta-1,3-diene-1-one, and buta-1,3-diene-1,4-diselenone were calculated using HF, B3LYP, and MP2 levels of theory and 6–31 + G* basis set by rotation around the related ‒C‒C‒ single bonds. In all of the above-mentioned molecules, the s-trans conformation was obtained as the most stable conformer with the 180° dihedral angle. In buta-1,3-diene-1,4-dithione, 4-selenoxobuta-1,3-diene-1-thione, and buta-1,3-diene-1,4-diselenone, the s-cis form of these compounds corresponded to the other energy-minimum geometry. Their skew geometries, with torsional angles approximately 100°, were a transition state for conformational interconversion between the two global minima forms. In 4-oxobuta-1,3-diene-1-thione and 4-selenoxobuta-1,3-diene-1-one, geometries with the C˭C‒C˭C dihedral angles about 51 and 43° (respectively) were attributed to the second energy-m...

The behavior of the OCN radical adsorbed on the external surface of H-capped (6,0), (8,0), and (10,0) zigzag single-walled carbon nanotubes was studied by using density functional calculations. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using the Gaussian 98 suite of programs. We present the nature of the OCN radical–surface interaction in selected sites of the nanotubes. Binding energies corresponding to adsorption of the OCN radical are calculated to be in the range 280–315 kJ mol−1. More efficient binding energies cannot be achieved by increasing the nanotube diameter. We also provide the effects of OCN radical adsorption on the electronic properties of the nanotubes.

An efficient synthesis of alkyl acylcarbamodithioates by reaction of acid chlorides with ammonium thiocyanate in the presence of thiols is described. The unusually large values of 5 J FH = 12–15 Hz, observed for alkyl (2-fluorobenzoyl)carbamodithioates provide information about Ar–C–N–H torsion in these compounds.

An efficient one-pot synthesis of functionalized thioureas is described via three-component reaction of benzoyl isothiocyanates, secondary amines, and alkyl propiolates in the presence of triphenylphosphine (20 mol%).

Three- component reaction of 4-hydroxy-2H-pyran-2-one, aldehydes, and malononitrile or ethyl cyanoacetate in the presence of ZnO nanoparticles as the catalyst is described as an efficient and green synthetic method for obtaining of pyrano[4,3-b]pyran derivatives in excellent yield. These reactions were also tested with 2'-hydroxyacetophenone under similar conditions and produced chromene derivatives.

1-Ethyl-3-methylimidazolium bromide was used as a green recyclable alternative to volatile organic solvents for KOH catalyzed three-component synthesis of diethyl alkylsulfanylmethylmalonates from aldehydes, diethyl malonate, and alkylthiols. A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid

A simple one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from the reaction of 2-chloro-1,3-dicarbonyl compounds with thioureas or thioamides in the presence of 1-butyl-3-methylimidazolium trifluoromethanesulfonate is described.

An efficient synthesis of ethyl 3-alkyl-4-oxo-2-thioxo-1,3-thiazolane-5-carboxylates via reaction of primary amines with CS2 in the presence of diethyl 2-chloromalonate is described.

Stable derivatives of pyrroles were prepared using multicomponent reactions of dialkyl acetylenedicarboxylate, primary amine and propiolate in the presence of N-methylimidazole in water at room temperature in good yields.

Minimum-energy and transition state geometries of 3-thioxoprop-2-enethial, 3-thioxoacrylaldehyde, 3-oxoprop-2-enethial, 3-selenoxoprop-2-enethial, 3-thioxoprop-2-eneselenal, 3-selenoxoprop-2-eneselenal, 3-oxoacrylaldehyde, 3-selenoxoacrylaldehyde and 3-oxoprop-2-eneselenal were calculated using HF, B3LYP and MP2 levels of theory and 6-31+G*basis set by rotation around the related -C-C- single bonds. In all of the above mentioned molecules, the s-trans conformation was obtained as the most stable conformer with the 180°dihedral angle, apart from 3-oxoprop-2-enethial and 3-thioxoprop-2-eneselenal which theirs-cisconformers were appeared more stability than related tos-transforms. Their perpendicular geometries, with torsional angles approximately 90°, were as transition state for conformational interconversion between the two global minima forms. Cyclic structures all of the above mentioned molecules were unstable than their linear forms.

Morpholinium fluorochromate(VI), MFC, is easily synthesized by reacting morpholine to an aqueous solution of CrO3and HF. This reagent selectively oxidizes aryl alcohols to their corresponding aldehydes and ketones under mild conditions. Moreover, it is inert towards aldehydes, ketons, oximes, thiols, sulfids, phenols, pyrans, trimethylsilanes, malonates and thioacetamides. The durability, reaction rate, ease of filtration and efficiency of MFC are considerably increased upon its absorption on silica gel.

An efficient synthesis of ethyl 3-alkyl-4-oxo-2-thioxo-1,3-thiazolane-5-carboxylates via reaction of primary amines with CS2 in the presence of diethyl 2-chloromalonate is described.

An efficient one-pot synthesis of functionalized thioureas is described via three-component reaction of benzoyl isothiocyanates, secondary amines, and alkyl propiolates in the presence of triphenylphosphine (20 mol%).