Ugi three-component coupling reaction for the synthesis of 2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazocin-5(6H)-yl)-2-phenylacetamide derivatives

A three-component, four center Ugi reaction of 3-(1-(2-aminophenyl)-5-phenyl-1H-pyrrol-2-yl)propanoic acid with aromatic aldehyde and t-butyl isocyanide has been achieved to produce a novel class of N-tert-butyl-2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazacine-5(6H)-yl)-2-phenylacetamides in moderate to good yields.     

Synthesis and in vitro and in vivo antitumor/anticancer activity of novel O-Mannich bases of 4,6-diaryl-3,4-dihydropyrimidine-2(1H)-ones

A new series of [4,6 substituted diaryl-1,6-dihydropyrimidin-2-yl-oxymethyl]-amines 5a–o have been synthesized by the Mannich condensation on the respective 4,6-diaryl-3,4-dihydropyrimidine-2(1H)-ones 4, in basic medium using formaldehyde along with three secondary amines, viz., dimethylamine, piperidine and morpholine. The dihydropyrimidinones 4 in turn were synthesized by the cyclocondensation of chalcones 3 with urea. Alternatively, compounds 4 were also prepared directly by one-pot 3-component cyclocondensation reaction starting from acetophenone, benzaldehyde and urea. The structures of all the newly synthesized compounds have been confirmed by their spectral and analytical data. All the O-Mannich bases 5 have been evaluated for their in vitro cytotoxic and antitumor activities, and based on the results, the potent compounds were selected for in vivo activity, as well. Only one compound 5m of the series has been found to be relatively more effective.     

Impact of Gd3+ and Nd3+ ions substitution on structural and magnetic properties of Co0.5Ni0.5Fe2O4 ferrite system

Co_0.5Ni_0.5(Gd/Nd)_xFe_2-xO₄ (x ?= ?0.0 and 0.06) ferrites were prepared by the solid-state reaction method. These materials were characterized by XRD, FT-IR spectroscopy, and VSM techniques. The XRD analysis revealed the phase formation of all samples and their cubic spinel structure with the Fd-3m space group. Lattice constant was found to increase due to Gd and Nd ions substitution. However, the crystallite size was observed to decrease by the substitution effect. The FT-IR spectra showed the two vibrational frequency bands of the tetrahedral and octahedral sites. From the magnetic properties study, it was identified that the pure and Gd substituted Co_0.5Ni_0.5Fe₂O₄ ferrite showed a ferromagnetic behaviour. While the Nd substituted Co_0.5Ni_0.5Fe₂O₄ ferrite delivered a superparamagnetic behaviour. The substitution of Gd and Nd changed the values of the magnetic parameters of Co_0.5Ni_0.5Fe₂O₄ ferrite. An increase in the saturation magnetization (M_s) value was observed due to substitution of Gd and Nd in Co_0.5Ni_0.5Fe₂O₄ ferrite, indicating that Gd and Nd substitution strengthen the supermagnetic interactions in Co_0.5Ni_0.5Fe₂O₄ ferrite. The highest value of M_s was observed in Gd doped sample.     

Layer-by-layer sensor architecture of polymers and nanoparticles for electrochemical detection of uric acid in human urine samples

Excessive uric acid levels in the human body (hyperuricemia) are the main causes of kidney stones and diabetes. In this study, a layer-by-layer arrangement of polymers and nanocomposites is used as a new electrode sensing material for rapid and direct electrochemical determination of uric acid (UA). The electrode surface architecture was constructed by the incorporation of poly (amidoamine) dendrimer with 0.5 generation (poly (amidoamine) [PAMAM] [D-G0.5]) of multiwalled carbon nanotube-silver nanoparticles (MWCNT-AgNP) and a poly (neutral-red) (poly [NR]) polymer. The PAMAM (D-G0.5)/MWCNT-AgNP/poly (NR)-coated electrode has a good electrocatalytic activity for the determination of UA using cyclic voltammetry and showed remarkable enhancement in current response at a low-oxidation potential (0.3 V). Under optimal conditions, the developed electrochemical sensor showed an excellent and wide linear range for the determination of UA (i.e. 0.016 μM–2500 μM), and the limit of detection was found to be 0.005 μM. The modified sensor system demonstrated excellent sensitivity and selectivity toward the detection of UA in the presence of interfering substances, which are commonly found in urine and human fluid samples. Furthermore, the developed sensor has represented both reproducibility and excellent stability for the UA determination in real samples (human urine).     

Nickel and Tungsten Bimetallic Nanoparticles Modified Pencil Graphite Electrode: A High-performance Electrochemical Sensor for Detection of Endocrine Disruptor Bisphenol A

In this work, an economically viable, very low cost, indigenous, ubiquitously available electrochemical sensor based on bimetallic nickel and tungsten nanoparticles modified pencil graphite electrode (NiNP-WNP@PGE) was fabricated for the sensitive and selective detection of bisphenol A (BPA). The NiNP-WNP@PGE sensor was prepared by a facile electrochemical one step co-deposition method. The prepared nanocomposite was morphologically characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), electrochemically by cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The proposed sensor displayed high electrocatalytic activity towards electro-oxidation of BPA with one irreversible peak. The fabricated sensor displayed a wide detection window between 0.025 μM and 250 μM with a limit of detection of 0.012 μM. PGE sensor was successfully engaged for the detection of BPA in bottled water, biological, and baby glass samples.     

Development of Pen-type Portable Electrochemical Sensor Based on Au-W Bimetallic Nanoparticles Decorated Graphene-chitosan Nanocomposite Film for the Detection of Nitrite in Water,Milk and Fruit Juices

The development and fabrication of a simple, portable, and sensitive detection tool to precisely monitor nitrite level is of growing importance in electrochemistry research, given the strong interest in the protection of drinking water quality, treatment of wastewater, food production, and control of remediation processes. This work describes the fabrication of a simple, cost-effective, pen-type electrochemical sensor based on bimetallic gold and tungsten nanoparticles electrochemically decorated on graphene-chitosan modified pencil graphite electrode (PGE) for the trace detection of nitrite in real samples. The prepared nanocomposite was characterized using XRD, SEM, and EDS. The electrochemical behavior of the sensor was evaluated by cyclic voltammetry (CV) and impedance electrochemical spectroscopy (EIS). Results revealed that the proposed sensor displayed excellent electrocatalytic activity towards electro-oxidation of nitrite with an irreversible redox reaction. The AuNPs-WNPs@Gr-Chi/PGE sensor exhibited excellent analytical performance with a wide linear range from 10 to 250 μM towards nitrite. The LOD and LOQ were calculated to be 0.12 μM and 0.44 μM, respectively. The designed electrochemical sensor was successfully applied for the detection of nitrite in water, milk, and natural fruit juice samples.     

Brønsted acid catalyzed synthesis of 2-aryl-quinazolinones via cyclization of 2-aminobenzamide with benzonitriles in PEG

A simple and efficient Brønsted acid catalyzed synthesis of 2-aryl-quinazolinones via cyclization of 2-aminobenzamides with benzonitrile in PEG under metal and ligand-free condition. All substituted benzonitriles were also well participated with the formation of the corresponding products in moderate to good yields.     

Design,synthesis, and biological activity studies of a new class of sulfonated aurones: First synthesis of acidoaurone isolated from Phyllanthus acidus

A novel series of aurones were designed by introducing sulfonic acid group on ring-A and ring-B of known natural aurones such as hispidol, sulfuretin, maritimetin, and aureusidin. These sulfonated aurones were synthesized by a unique approach. Sulfonation on ring-A or ring-B converts water-insoluble aurones into highly water-soluble aurones. The sulfonated aurones were tested for their antioxidant, antiinflammatory, and AChE inhibition activities along with their natural aurones. Ring-A sulfonated aurones displayed higher antioxidant activity, 5-LOX, and AChE inhibition in comparison with their corresponding natural aurones. Ring-B sulfonated aurones exhibited potent 5-LOX inhibitory activity and significant antioxidant activity. Acidoaurone, a first sulfonated aurone isolated from Phyllanthus acidus was synthesized for the first time and was well characterized using NMR, LC–MS, and further confirmed by HMBC.