Clay based heterogeneous catalysts for carbon-nitrogen bond formation: a review.

Clay and modified clay-based catalysts are widely used in organic transformation. Owing to the interlayer ions and good ion exchange capacity of clay, replacement with another ion and incorporation of different nanomaterials can be done. Due to these significant properties of clay, it can be utilized in the synthesis of various organic compounds. Carbon-nitrogen bonded compounds possess diverse applications in different fields. These compounds are prepared using different solid acid heterogeneous catalysts. This review presents a detailed discussion on clay used for the carbon-nitrogen bond formation reaction, such as the Biginelli reaction and A3 and KA2 coupling reactions. Additionally, other C-N bond formation reactions using various clay-based catalysts such as bentonite, montmorillonite, hydrotalcite and halloysite clay with various metals, metal oxides, Kegging type heteropoly acid and various nanomaterial incorporated clay heterogeneous catalysts are discussed.

Biosynthesis and computational analysis of amine-ended dual thiol ligand functionalized gold nanoparticles for conventional spectroscopy detection of melamine.

The bio-synthesized DTAuNPs have an average size of 21nm. The aggregation extent depends on the concentration of melamine, which was validated by UV-vis spectra and visual method of melamine detection was developed. The major observation in this method was the color change of DTAuNPs from red to purple due to the aggregation of ligand capped gold nanoparticles instigated by melamine. The reaction of color changes were processed due to the shifting of bonding in hydrogen in between nanoparticles and melamine. The aggregation extent depends on the concentration of melamine, which can be validated UV-vis spectra and visual method of detecting melamine is developed. The electron density and conventional UV-vis, FTIR spectroscopy and DFT studies on the ligand was performed using computational methods. The theoretical and experimental data for the energy transitions and the molar extinction coefficients of the ligands studied has been obtained. Further, the ligand capped gold nanoparticles was assessed for cytotoxicity against A549 cells which resulted in significant decrease in cell viability was noted in 50µg/mL DTAu, 4-ATP and AXT treated cells at 2h (85% and 66%) and 6h (83% and 36%) respectively, (p<0.01) were studied and reported in this manuscript.

Synthesis and insecticidal activity of acridone derivatives to Aedes aegypti and Culex quinquefasciatus larvae and non-target aquatic species.

A serious Mosquito borne yellow fever is one of the grave diseases which affect the major population. Since there is no specific treatment for yellow fever, there is a necessity to develop an effective agent. The series of acridinone analogues 3 to 5 were synthesized with help of non-conventional microwave heating and confirmed by respective spectral characterization. 5c and 3b showed highest activity to kill 90% of larvae against A. aegypti and C. quinquefasciatus, respectively. Also the active products were treated to check the mortality of non-target aquatic species. Through the reports of the larvicidal bioassay, compounds 3b against C. quinquefasciatus whereas 5c against A. aegypti were found to be more active. By keeping this as a platform, further extension of the work can be done to find out a valuable drug for controlling disease vectors.

Synthetic strategy with representation on mechanistic pathway for the therapeutic applications of dihydroquinazolinones.

Dihydroquinazolinones is an important core structure reported with a wide variety of pharmacological activities. They are capable of undergoing various transformations because of its reactivity towards various reagents. The synthetic strategies for the functionalization and derivatization of the nucleus were explained. The diversified pharmacological actions of this moiety were illustrated through various biochemical pathways. The structural-activity relationship study of dihydroquinazolinones anticipated the relationship between the various substituents and its role in the pharmacological action. The main objective of this review is to summarize the importance of dihydroquinazolinones in the field of chemical biology.

Application of UV-Vis spectrophotometric process for the assessment of indoloacridines as free radical scavenger.

A conventional approach has been used to synthesis Indole fused acridine, 4a-e. In this paper to achieve the target molecule, 4 the reaction was performed via two steps. In step 1, there was a reaction between Carbazolone, 1 and benzophenone, 2 to get dihydroindoloacridine, 3. In step 2, compound, 3 was treated with 5% Palladium/Carbon in the presence of diphenyl ether for 5h to give a dark brown product, 4. The column chromatography was used to purify final product, 4. All the synthesized compounds such as 3 and 4 were characterized by melting point, FTIR, (1)H NMR, and Mass spectra. Further to check the purity of the compounds it was subjected to CHN analyzer. The target molecules such as 3 and 4 were screened for antimicrobial studies against bacteria such as Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Klebsiella pneumonia (K. pneumonia), Salmonella typhi (S. typhi); and fungi like Aspergillus niger (A. niger), Aspergillus fumigatus (A. fumigatus). The obtained results clearly proves that the target molecules shown reasonable activity against K. pneumonia and A. niger. Further the compounds were screened for free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH). The free radical scavenging property was performed using UV-Visible spectroscopy. The results were compared with the standard BHT (Butylated Hydroxy Toluene). Compounds, 4a and 4e were shown higher percentage of inhibition when compare to the standard. The result confirms that further research on indoloacridine will leads effective drug to the market.

Photocatalytic degradation of Congo red using Carissa edulis extract capped zinc oxide nanoparticles.

The use of plant extract to synthesize nanoparticle has been considered as one of the eco-friendly method. Additionally, it is a strong alternate for conventional methods which includes chemical and physical approach. In this study, microwave assisted extraction of Carissa edulis (C. edulis) at 70°C and 400W was used to extract the secondary metabolites. Further, the metabolites were used as capping agent and Zn (NO3)2 as the metal precursor to synthesize ZnO nanoparticles (ZnO NPs). UV-Vis spectroscopy, FT-IR, XRD, SEM and HR-TEM were used for the characterization of nanoparticles. The Surface Plasmon Resonance around 358nm from the UV-Vis spectroscopy result represents the ZnO NPs formation. The FT-IR confirms the presence of functional groups that acts as the capping agent for the synthesis of ZnO NPs. The crystalline structure of nanoparticles is revealed in the XRD result, morphology showed by SEM results and the size of the ZnO NPs were predicted by HR-TEM. We have carried out the photocatalytic degradation of Congo red at 365nm in photo reactor using ZnO NPs. The result from the photocatalytic degradation Congo red showed rate constant is (-k) 0.4947 with 97% of degradation. This is our first attempt on the C. edulis extract on ZnO NPs preparation and Congo red dye degradation revels that ZnO NPs exhibit good photocatalytic property.

Importance of fluorine in 2,3-dihydroquinazolinone and its interaction study with lysozyme.

The main aim of this study is to investigate the interaction of 7-fluoro-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-one with lysozyme through various spectrophotometric studies. The graph such as Stern-Volmer plot, modified Stern Volmer plot, double logarithmic plot and Van't Hoff plot were plotted to determine the various parameters essential for predicting the interaction. The interaction of the ligand with the protein was further confirmed by circular dichroism and NMR study. The molecular docking was performed and the results obtained were correlated with the other studies. The importance of fluorine was justified through the prediction of pKa values and the possible metabolic pathway using the in silico tools. In addition, the cytotoxicity of the compound was carried out using HeLa cancer cell.

Inhibition of poly(adenosine diphosphate-ribose) polymerase using quinazolinone nucleus.

Poly(adenosine diphosphate-ribose) polymerase (PARP) is a group of enzymes with several subtypes and it manages various ailment such as cancer, inflammatory disorders, diabetes mellitus, neuronal injury, HIV infection, Parkinsonism, aging, and ischemia-reperfusion injury. Various PARP inhibitors share a common property of bicyclic lactam in its main structural frame. The core moiety containing bicyclic lactam rings are isoquinolinones, dihydroisoquinolinones, quinazolinediones, phthalazinones, quinazolinones, and phenanthridones. The quinazolinone with diverse substituents displayed low nanomolar inhibition. Quinazolinone is an important and vital molecule in the field of medicinal chemistry possessing multitude pharmacological actions. Though the chemistry of quinazolinones has been discussed through centuries, its concise role on PARP inhibition needed a special consideration. The aim of this review is to discover the effect of quinazolinone substitutents and its role in PARP inhibition. This precise review will discuss the effect of quinazolinones on PARP subtypes such as PARP-1, PARP-2, PARP-5a, and PARP-5b. In addition to its pharmacological actions, PARP inhibitors can also act as a chemosensitizing agent, and it is used in combination with the other anticancer agents. This summarization will definitely be a supportive report for the scientist working toward the novelty in the quinazolinone nucleus and its role in PARP inhibition.

Binding mode of dihydroquinazolinones with lysozyme and its antifungal activity against Aspergillus species.

Aspergillosis is one of the infectious fungal diseases affecting mainly the immunocompromised patients. The scarcity of the antifungal targets has identified the importance of N-myristoyl transferase (NMT) in the regulation of fungal pathway. The dihydroquinazolinone molecules were designed on the basis of fragments responsible for binding with the target enzyme. The aryl halide, 1(a-g), aryl boronic acid and potassium carbonate were heated together in water and dioxane mixture to yield new CC bond formation in dihydroquinazolinone. The bis(triphenylphosphine)palladium(II) dichloride was used as catalyst for the CC bond formation. The synthesized series were screened for their in vitro antifungal activity against Aspergillus niger and Aspergillus fumigatus. The binding interactions of the active compound with lysozyme were explored using multiple spectroscopic studies. Molecular docking study of dihydroquinazolinones with the enzyme revealed the information regarding various binding forces involved in the interaction.

2,3-Dihydroquinazolin-4(1H)-ones: visible light mediated synthesis, solvatochromism and biological activity.

The photochemical synthesis of a series of 2,3-dihydroquinazolin-4(1H)-ones were evaluated under the irradiation of visible light (>390nm). The effect of the visible light mediated synthesis was carried out in the presence/absence of solvent. The effect of solvent plays a key role in the synthesis was evidenced through the formation of product in short duration. The solvatochromic effects of the fluorescent compounds (3a-k) were studied with respect to the solvents of increasing polarity (DCM

Role of dried fruits of Carissa carandas as anti-inflammatory agents and the analysis of phytochemical constituents by GC-MS.

Inflammation plays an important role in various diseases with high prevalence within populations such as rheumatoid arthritis, ulcer, atherosclerosis, and asthma. Many drugs are available in the market for inflammatory diseases. They exhibit several unwanted side effects to humans. Therefore, alternative treatments with safer compounds are needed. Carissa carandas plant is used in traditional medicinal system for its various diseases curing property. In the present study, we examined the anti-inflammatory effects of dried fruit methanol extract on carrageenan-induced hind paw edema in rats. C. carandas was defatted with petroleum ether, followed by methanol extraction. The methanol extracts of the dried fruits of Carissa carandas were given orally to the experimental rats caused significant activity (P ≤ 0.05) when compared with the control group. The maximum inhibition of paw edema was found to be in Group V, that is, 76.12% with inhibition of paw volume in a dose-dependent manner. The anti-inflammatory activity of the methanol extract of the dried fruits shows that the presence of potential constituents present in this extract may provide assistance in the drug discovery process. The phytochemical compounds of the extract were screened by GC-MS analysis and it was found that 11 compounds are present in methanol extract of dried fruits of Carissa carandas.

Efficient phyto-synthesis and structural characterization of rutile TiO2 nanoparticles using Annona squamosa peel extract.

In the present study, the biosynthesis of rutile TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using fruit peel Annona squamosa aqueous extract. This is the first report on the new, simple, rapid, eco-friendly and cheaper methods for the synthesis of rutile TiO(2) NPs at lower temperature using agricultural waste. Rutile TiO(2) NPs were characterized by UV, XRD, SEM, TEM and EDS studies. The UV-Vis spectrophotometer results were promising and showed a rapid production of TiO(2) NPs with a surface plasmon resonance occurring at 284 nm. The formation of the TiO(2) NPs as observed from the XRD spectrum is confirmed to be TiO(2) particles in the rutile form as evidenced by the peaks at 2θ=27.42°, 36.10°, 41.30° and 54.33° when compared with the literature. The TEM images showed polydisperse nanoparticles with spherical shapes and size 23±2 nm ranges.

Free radical scavenging and reducing power of Lawsonia inermis L. seeds.

OBJECTIVE: To determine the antioxidant activity, total phenolic and flavonoid content of Petroleum ether extract (PE), Dichloromethane extract (DCM), Ethanol extract (ET) and aqueous extract (AQ) of henna seeds. METHODS: Total antioxidant assay (phosphomolybenum method), DPPH radical scavenging assay, reducing power assay and lipid peroxidation inhibition assay were used to ascertain the potential of seeds as an antioxidant. RESULTS: In all the assays carried out ET showed a greater potential to scavenge DPPH radical, reduce MO (VI) to MO (V) complex and Fe (III) to Fe (II) and to inhibit lipid peroxidation. The IC(50) of ET was far greater than that of the standard, ascorbic acid (AS) in the lipid peroxidation assay. The activity of AQ was lesser when compared with that of ET but greater than PE and DCM. The amount of phenolics and flavonoids were present in higher amounts in ET followed by AQ. Trace amounts of phenolics were detected in PE and DCM, but the amount of flavonoids were below the detection level. The study showed that the antioxidant activity and the concentrations of phenolics and flavonoids are proportionate to each other. CONCLUSIONS: Ethanolic extract of henna seeds are efficient antioxidants, which can be utilized for further isolation of active compounds and pharmaceutical applications.

Preliminary phytochemical analysis, antibacterial, antifungal and anticandidal activities of successive extracts of Crossandra infundibuliformis.

OBJECTIVE: To investigate the phytochemical, antibacterial, antifungal and anticandidal activity of successive extracts of Crossandra infundibuliformis (Acanthaceae) leaves. METHODS: Preliminary screening on the presence of alkaloids, saponins, phytosterols, phenolic compounds, flavanoids, tannins, carbohydrates, terpenoids, oils and fats were carried out by phytochemical analysis. The antibacterial, antifungal and anticandidal activities were done by agar well diffusion technique. RESULTS: The successive extracts have an array of chemical constituents and the MIC values of antibacterial activity ranges from 0.007 8 to 0.015 0 µg/mL. In case of antifungal and anticandidal activities the MIC values were between 0.125 and 0.250 µg/mL. CONCLUSIONS: These findings demonstrate that the leaf extracts of C. infundibuliformis presents excellent antimicrobial activities and thus have great potential as a source for natural health care products.