Nonsteroidal Anti‐inflammatory Drug‐based N‐Allylidene Benzohydrazides and 1‐Acyl‐2‐pyrazolines: Their Synthesis as Potential Cytotoxic Agents In Vitro

A series of 1‐acyl‐2‐pyrazoline derivatives derived from nonsteroidal anti‐inflammatory drugs was designed as potential anticancer agents. Synthesis of these compounds was carried out via the condensation reaction of chalcones and acid hydrazides under heating. The methodology did not require the use of any costly reagents or catalysts, and the acid hydrazide reactants were readily prepared from mefenamic acid or ibuprofen. A variety of 1‐acyl‐2‐pyrazolines was prepared in good to excellent yields. An N‐allylidene benzohydrazide intermediate was isolated during the reaction optimization study, the structure of which was confirmed unambiguously by X‐ray single crystal data. A range of N‐allylidene benzohydrazides were also prepared in good yields. Some of the compounds synthesized showed promising cytotoxic activities when tested against HCT‐15 human colon cancer cell line in vitro.     

Synthesis and Characterization of Silver–PVA Nanocomposite for Sensor and Antibacterial Applications

Silver–polyvinyl alcohol (PVA) nanocomposite is synthesized by a simple chemical reduction method in aqueous media and characterized by various techniques such as UV–Visible spectroscopy, transmission electron microscopy, X-ray diffraction and infrared spectroscopy. The morphology of the obtained silver nanoparticles is spherical in shape with an average diameter of 24 nm. The prepared silver–PVA nanocomposite is demonstrated to detect the concentration of heavy metal contaminant cadmium in water based on linear change in surface plasmon resonance absorption strength. The antibacterial tests show the inhibiting action of this nanocomposite against pathogenic bacteria Escherichia coli and Pseudomonas aeruginosa (gram negative), Bacillus cereus and Staphylococcus aureus (gram positive), which are found commonly in water. These observed optical and antibacterial properties, suggest the possible utilization of prepared silver–PVA nanocomposite in the water purification application.     

Mass spectrometry combined with affinity probes for the identification of CP4 EPSPS in genetically modified soybeans

Sample preparation methods used for genetically modified organisms (GMOs) analysis are often time consuming, require extensive manual manipulation, and result in limited amounts of purified protein, which may complicate the detection of low‐abundance GM protein. A robust sample pretreatment method prior to mass spectrometry (MS) detection of the transgenic protein (5‐enolpyruvylshikimate‐3‐phosphate synthase [CP4 EPSPS]) present in Roundup Ready soya is investigated. Liquid chromatography‐multiple reaction monitoring tandem MS (nano LC‐MS/MS‐MRM) was used for the detection and quantification of CP4 EPSPS. Gold nanoparticles (AuNPs) and concanavalin A (Con A)‐immobilized Sepharose 4B were used as selective probes for the separation of the major storage proteins in soybeans. AuNPs that enable the capture of cysteine‐containing proteins were used to reduce the complexity of the crude extract of GM soya. Con A‐sepharose was used for the affinity capture of β‐conglycinin and other glycoproteins of soya prior to enzymatic digestion. The methods enabled the detection of unique peptides of CP4 EPSPS at a level as low as 0.5% of GM soya in MRM mode. Stable‐isotope dimethyl labeling was further applied to the quantification of GM soya. Both probes exhibited high selectivity and efficiency for the affinity capture of storage proteins, leading to the quantitative detection at 0.5% GM soya, which is a level below the current European Union's threshold for food labeling. The square correlation coefficients were greater than 0.99. The approach for sample preparation is very simple without the need for time‐consuming protein prefractionation or separation procedures and thus presents a significant improvement over existing methods for the analysis of the GM soya protein.     

Recent advances in the synthetic chemistry of 1,5-benzothiazepines: A minireview

Benzothiazepine, a prominent “drug prejudice core”, is a heterocyclic moiety of immense importance due to its presence in a wide range of bioactive compounds. They act as a primary “biolinker” in diverse synthetic routes to obtain bioactive molecules and serve as important templates in synthetic and medicinal chemistry. They are known to possess a plethora of pharmacological activities, which include Ca²⁺ channel blockers, CNS acting agents, anti-HIV, ACE inhibitors, antimicrobial, antifungal, anticancer. Their promising behaviour as drug molecules led the scientific community to develop novel, mild, green, and highly efficient synthetic routes for their synthesis. The conventional synthesis generally involved the condensation of chalcones with 2-aminothiophenol in the presence of acid/base with high-temperature heating, mostly resulting in poor yields or mixtures. However, recent trends are replacing these conditions with mild and green conditions through organocatalysis or other methodologies. In this review, an attempt has been made by authors to summarize (a) Recent developments in the synthetic strategies of 1,5-benzoathiazepines and its derivatives (b) Conventional methods for the synthesis of 1,5-benzothiazepines including progress in the green chemistry routes (c) Applications of various metals and organocatalysts to achieve the enantioselective synthesis of title compounds.     

One pot synthesis of novel dispiro[oxindole‐thiazolidinedione/thioxo‐thiazolidinone/dihydro pyrazolone]‐pyrrolidines via 1,3‐dipolar cycloaddition reaction of azomethine ylides

A series of novel dispiro[oxindole‐thiazolidinedione]pyrrolidine, dispiro[oxindole‐thioxothiazolidinone]‐pyrrolidine, dispiro[oxindole‐dihydro‐pyrazolone]pyrrolidine were synthesized by both regio‐ and stereo‐selective 1,3‐dipolar cycloaddition reaction of azomethine ylide generated from amino acid and amino acid ester with π‐deficient alkenes in a single pot protocol in good yield. X‐ ray crystallographic studies established orthogonal disposition between spiro‐oxindole and spiro‐thiazolidinedione rings in 4a and 5a .     

Synthesis and antimicrobial activity of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones

A series of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones 4a , 4b , 4c , 4e , 4f , 4g , 4h , 4i , 4j have been synthesized and assayed for their antibacterial activity against Gram‐positive bacteria viz. Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), Micrococcus luteus (IFC 12708), and Gram‐negative bacteria viz. Proteus vulgaris (ATCC 3851), Salmonella typhimurium (ATCC 14028), Escherichia coli (ATCC 25922), and also antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), and Trichophyton mentagrophytes (IFO 40996). Among the screened compounds, 4d , 4e , 4f , 4g , and 4j exhibited potent inhibitory activity compared with the standard drug at the tested concentrations. The results reveal that, the presence of difluorophenyl in 4f and pipernyl ring in 4j at 2‐position of thiazolidine‐4‐one ring show significant inhibitory activity. The other compounds also showed appreciable activity against the test bacteria and fungi and emerged as potential molecules for further development. J. Heterocyclic Chem., 2011.     

Quantitative estimation of constituents in fly ash by lithium tetraborate fusion

Silica is removed from fly ash sample by hydroflourination for its effective determination gravimetrically and the remaining residue is subjected to lithium tetraborate (Li₂B₄O₇) fusion followed by dissolution in dilute nitric acid to obtain a clear solution in which elements including aluminum (Al), iron (Fe), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu) and zinc (Zn), have been determined by Flame Atomic Absorption Spectrometry (FAAS). Two fly ash samples analyzed by the proposed method have been received from the National Council of Cement and Building Materials (NCCBM), India (proposed CRM in future) and fly ash CRM 1633 (b) from NIST, USA. The validity of the method has been established by analyzing fly ash CRM 1633 (b) as reference standard. The standard deviation has been calculated for each measurement.     

Chiral discrimination of D- and L-amino acids using iodinated tyrosines as chiral references: Effect of iodine substituent

L-Tyrosine and iodinated L-tyrosines, i.e., 3-iodo-L-tyrosine and 3,5-diiodo-L-tyrosine, are successfully used as chiral references for the chiral discrimination of aliphatic, acidic, and aromatic amino acids. Chiral discrimination is achieved by investigating the collision-induced dissociation spectra of the trimeric complex [Cu(II)(ref)(2)(A) - H](+) ion generated by electro spraying the mixture of D- or L-analyte amino acid (A), chiral reference ligand (ref) and M(II)Cl(2) (M = Ni and Cu). The relative abundances of fragment ions resulted by the competitive loss of reference and analyte amino acids are considered for measuring the degree of chiral discrimination by applying the kinetic method. The chiral discrimination ability increases as the number of iodine atom increases on the aromatic ring of the reference and the discrimination is better with Cu when compared with Ni. A large chiral discrimination is obtained for aliphatic and aromatic amino acids using iodinated L-tyrosine as the reference. Computational studies on the different stabilities of the diastereomeric complexes also support the observed differences measured by the kinetic method. The suitability of the method in the measurement of enantiomeric excess over the range of 2% to 100% ee with relative error 0.28% to 1.6% is also demonstrated.     

Structure elucidation of thermal degradation products of amlodipine

Thermal degradation of amlodipine base causes intramolecular reactions affording three cyclic products, referred to as AMLDEG-I, AMLDEG-II, and AMLDEG-III, respectively. AMLDEG-I is a cyclized product formed by intramolecular elimination of ammonia from amlodipine. AMLDEG-II is a positional isomer of AMLDEG-I. AMLDEG-III is also intramolecular cyclisation product. The three degradation products were isolated by column chromatography and characterized by FT-IR and 1H and 13C NMR spectroscopy data. The AMLDEG-III was crystallized and its structure was solved by single crystal X-ray diffraction (SXRD).