Search

Optimal cell spreading and interplay of vascular smooth muscle cells (VSMC), inflammatory cells, and cell adhesion molecules (CAM) are critical for progressive atherosclerosis and cardiovascular complications. The role of vitronectin (VTN), a major cell attachment glycoprotein, in the pathogenesis of atherosclerosis remains elusive. In this study, we attempt to examine the pathological role of VTN in arterial plaque progression and inflammation. We found that, relative expression analysis of VTN from the liver of Apolipoprotein E (ApoE) Knockout mice revealed that atherosclerotic progression induced by feeding mice with high cholesterol diet (HCD) causes a significant downregulation of VTN mRNA as well as protein after 60 days. Promoter assay confirmed that cholesterol modulates the expression of VTN by influencing its promoter. Mimicking VTN reduction with siRNA in HCD fed ApoE Knockout mice, accelerated athero‐inflammation with an increase in NF‐kB, ICAM‐1, and VCAM‐1 at the site of the plaque along with upregulation of inflammatory proteins like MCP‐1 and IL‐1β in the plasma. Also, matrix metalloprotease (MMP)‐9 and MMP‐12 expression were increased and collagen content was decreased in the plaque, in VTN deficient condition. This might pose a challenge to plaque integrity. Human subjects with acute coronary syndrome or having risk factors of atherosclerosis have lower levels of VTN compared to healthy controls suggesting a clinical significance of plasma VTN in the pathophysiology of coronary artery disease. We establish that, VTN plays a pivotal role in cholesterol‐driven atherosclerosis and aortic inflammation and might be a useful indicator for atherosclerotic plaque burden and stability.

Abiotic stresses have a detrimental impact on plant growth and productivity and are a major threat to sustainable crop production in rapidly changing environments. Proline, an important amino acid, plays an important role in maintaining the metabolism and growth of plants under abiotic stress conditions. Many insights indicate a positive relationship between proline accumulation and tolerance of plants to various abiotic stresses. Because of its metal chelator properties, it acts as a molecular chaperone, an antioxidative defence molecule that scavenges reactive oxygen species (ROS), as well as having signalling behaviour to activate specific gene functions that are crucial for plant recovery from stresses. It also acts as an osmoprotectant, a potential source to acquire nitrogen as well as carbon, and plays a significant role in the flowering and development of plants. Overproduction of proline in plant cells contributes to maintaining cellular homeostasis, water uptake, osmotic adjustment and redox balance to restore the cell structures and mitigate oxidative damage. Many reports reveal that transgenic plants, particularly those overexpressing genes tailored for proline accumulation, exhibit better adaptation to abiotic stresses. Therefore, this review aims to provide a comprehensive update on proline biosynthesis and accumulation in plants and its putative regulatory roles in mediating plant defence against abiotic stresses. Additionally, the current and future directions in research concerning manipulation of proline to induce gene functions that appear promising in genetics and genomics approaches to improve plant adaptive responses under changing climate conditions are also highlighted.

A new heterogeneous catalyst, lanthanum immobilized on chitosan, was synthesized and used for the aza-Michael reaction of β-enaminone under microwave irradiation. The characteristic structural features of the catalyst were determined using Fourier transform infrared spectroscopy, powder X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission and scanning electron microscopies and inductively coupled plasma atomic emission spectroscopy. The stability of the catalyst was evaluated using thermogravimetric analysis. The use of recyclable catalyst and glycerol as solvent makes this procedure environmentally benign and economically viable. Copyright © 2016 John Wiley & Sons, Ltd.

Piperidine-functionalized silica as a basic heterogeneous catalyst was synthesized via a simple protocol by condensing silica chloride with piperidine. The catalyst was characterized with various techniques (FT-IR, solid state NMR, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric, elemental, and NH3 and CO2 temperature-programmed desorption analyses). Surface area was also evaluated through Brunauer–Emmett–Teller analysis. Its catalytic activity was evaluated for Claisen–Schmidt condensation under solvent-free conditions. The catalyst was easily recovered and reused up to five cycles without considerable loss of activity and was not deactivated due to amide formation. Also, this method has attractive advantages such as short reaction time, mild reaction conditions, good to excellent yield of products, easy handling of the catalyst and simple operational procedure. Copyright © 2014 John Wiley & Sons, Ltd.

A solvent-free and highly efficient protocol has been developed for the synthesis of novel bis-Michael addition products (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n, 3o) using aminopropylated PEG-6000 (NH2-PEG) as a biodegradable and recyclable catalyst in excellent yields under solvent-free conditions. Other remarkable features of this environmentally benign protocol are shorter reaction time, tolerance of a wide range of C―H-activated acids, high yield of products, and simple experimental and work-up procedure as compared to conventional methods. The NH2-PEG catalyst is characterized by using FT-IR, powder XRD and scanning electron microscopy–energy dispersion X-ray spectrometric analyses. The catalyst can be recycled several times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.

Mesoporous silica (MCM-41) supported perchloric acid has been synthesized efficiently via wet impregnation method. The new catalyst is characterized well with small angle X-ray scattering, FT-IR, BET, TGA, EDX, SEM analyses, and chemical mapping technique. The catalytic activity of the catalyst has been tested for Biginelli reaction via multicomponent route. Good to excellent yields of products were obtained in shorter time period.

The applied catalyst is readily prepared in two steps and can be reused at least five times.

A chitosan supported Dy(III) nanocatalyst was synthesised by a simple procedure. It was used as a catalyst for one pot, three component synthesis of hexahydropyrimidine derivatives. All the reactions were completed in a short time period at room temperature and the products were obtained in high to excellent yields. The catalyst was characterized by FT-IR, XRD, SEM-EDX, TEM and ICP-AES analyses. The stability of the catalyst was evaluated by TG analysis. Use of water, ambient conditions, recyclability and high TOF of the catalyst make this protocol a sustainable alternative to existing protocols.

A facile solvent-free protocol for the reaction of β-enaminone (II) with a variety of active methylene compounds and ammonium acetate to afford pyridine derivatives in excellent yields is developed.

Optimum reaction conditions are studied for the three-component synthesis of functionalized tetrazole derivatives under microwave irradiation.

Piperidine-functionalized silica as a basic heterogeneous catalyst was synthesized via a simple protocol by condensing silica chloride with piperidine. The catalyst was characterized with various techniques (FT-IR, solid state NMR, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric, elemental, and NH3 and CO2 temperature-programmed desorption analyses). Surface area was also evaluated through Brunauer–Emmett–Teller analysis. Its catalytic activity was evaluated for Claisen–Schmidt condensation under solvent-free conditions. The catalyst was easily recovered and reused up to five cycles without considerable loss of activity and was not deactivated due to amide formation. Also, this method has attractive advantages such as short reaction time, mild reaction conditions, good to excellent yield of products, easy handling of the catalyst and simple operational procedure. Copyright © 2014 John Wiley & Sons, Ltd.

The reaction of nitriles (II) with aryl mono- and dialdehydes and a variety of C—H-acidic substrates gives the pyran-annulated products in excellent yields.

A solvent-free and highly efficient protocol has been developed for the synthesis of novel bis-Michael addition products (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n, 3o) using aminopropylated PEG-6000 (NH2-PEG) as a biodegradable and recyclable catalyst in excellent yields under solvent-free conditions. Other remarkable features of this environmentally benign protocol are shorter reaction time, tolerance of a wide range of C―H-activated acids, high yield of products, and simple experimental and work-up procedure as compared to conventional methods. The NH2-PEG catalyst is characterized by using FT-IR, powder XRD and scanning electron microscopy–energy dispersion X-ray spectrometric analyses. The catalyst can be recycled several times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.

Tosic acid on silica gel (TsOH-SiO2) was synthesized and characterized using microscopic and spectroscopic techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Thermal behaviour of the catalyst was investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. TsOH-SiO2 showed excellent catalytic activity for the Knoevenagel condensation and was recyclable for six cycles.

Treatment of coumarine derivative (I) with different active methylene compounds in the presence of catalytic amounts of sulfamic acid results in the formation of pyranocoumarins via a Knoevenagel condensation/Michael addition/cyclization sequence.

NH2SO3H–SiO2/water as a novel catalytic system was used for the synthesis of (α,β-unsaturated) β-amino ketones via aza-Michael reaction at reflux conditions. The methodology was of general applicability and the catalyst exhibited activity up to five cycles. The catalyst was characterized for the first time using FT-IR, X-ray diffraction and scanning electron microscopic–energy dispersion analytical X-ray. The stability of the catalyst was evaluated by differential scanning calorimetry and TGA/differential thermal analysis. High efficiency of the catalyst along with its recycling ability and the rather low loading demonstrated in reactions are the merits of the presented protocol. Copyright © 2013 John Wiley & Sons, Ltd.

A convenient one-pot procedure using ZnO-nanoparticles as the catalyst allows the synthesis of pyranyl pyridine derivatives via a Michael addition, cyclodehydration, and elimination sequence in short reaction times.

Title compounds such as (III), (V), (VII), (IX), (XI), (XIII) and (XV) are prepared from coumarin (I) and corresponding active methylene compounds.

Optimized reaction conditions including PEG-OSO3H as the catalyst allow the synthesis of bis-Knoevenagel adducts in excellent yields from terephthalaldehyde with various acyclic and cyclic active methylene compounds.

NH2SO3H–SiO2/water as a novel catalytic system was used for the synthesis of (α,β-unsaturated) β-amino ketones via aza-Michael reaction at reflux conditions. The methodology was of general applicability and the catalyst exhibited activity up to five cycles. The catalyst was characterized for the first time using FT-IR, X-ray diffraction and scanning electron microscopic–energy dispersion analytical X-ray. The stability of the catalyst was evaluated by differential scanning calorimetry and TGA/differential thermal analysis. High efficiency of the catalyst along with its recycling ability and the rather low loading demonstrated in reactions are the merits of the presented protocol. Copyright © 2013 John Wiley & Sons, Ltd.

The simple and environmentally benign synthesis of the title compounds (III) proceeds under mild reaction conditions using water as solvent and Zn(L-proline)2 as recyclable and non-toxic catalyst.

Condensation of chromone derivatives (I) with cyclic active methylene compounds is best accomplished in refluxing water.

Hydroxycoumarin (I) and aromatic aldehydes undergo the Zn-catalyzed reaction in water to give the desired (arylmethylene)dicoumarols in

The cross-aldol condensation of 3-formylchromones with a series of acetyl-substituted heterocycles is investigated under optimized conditions.

4 Compounds of type (IV) or (VI) are prepared and screened for their antibacterial activities.

The title compounds are obtained in the reaction of coumarin (I) with various heteroaldehydes.

Simple thermal heating under neat conditions gives access to new chalcones (III) which are then converted to the corresponding pyrazolines (IV) in a solvent-free reaction.

Compounds (III) and (Vb) show moderate antibacterial activities against E.coli and S.dysenteriae.

The photochemical behavior of the 2-aryl substituted chromones (I) and (VI) respectively is studied and the product formation is explained on the basis of type-II hydrogen abstraction by the excited carbonyl function.

The onc pot and facile condensation reaction of 5-chloro-3-methyl-l-phenylpyrazole-4-carboxaldehyde 1, 5-azido-3-methyl-1-phenylpyrazole-4-carboxaldehyde 2 with triacetic acid lactone 3 and 4-hydroxycoumarin 4 affords isomeric pyrazolopyrones viz. 4-(4-hydroxy-6-methyl-2-oxo-2//-pyran-2-one-3-yl)-3,7-dimetyl-1-phenylpyrazolo|3,4:2,3|-4//-pyrano |3,2-b|pyran-5-one 6, 4-(4-hydroxy-6-methyl-2-oxo-2//-pyran-2-one-3-yl)-3,7-dimethyl -l-phenylpyrazolo|3.4:2,3|-4//-pyrano|3.2-c|pyran-5-one 7 and 4-(4-hydroxoy-2-oxo-2//-1-benzopyran-2-one-3-yl)-3-methyl-1-phenyl-pyrazolo[3,4:2,3]-4//-pyrano[3,2-b]-1-benzopyran-5-one 8, 4-(4-hydroxy-2-oxo-2//-I-benzopyran-2-onec-3-yl)-3-methyl-1-phenyl-pyrazolo|3,4:2.3|-4//-pyrano[3,2-c]-1-benzopyran-5-one 9 respectively. The condensation reaction which has led to the formattion of isomeric compounds is similar to Simonis condensation reaction of oxoesters. The structures of all newly synthesized compounds have been determined by IR, 1 II NMR and mass spectral data.