Aromatic Amine Compounds Research Articles

B(C6F5)3·H2O-Catalyzed N-H and C-H Functionalization of Aromatic Amines with Sulfoxonium Ylides under Metal-Free Conditions.

Hydrogen-bonded aggregates of B(C6F5)3 and water are proven as strong Brønsted acid catalysts, which have the advantages of low toxicity and broad compatibility. Sulfoxonium ylides are stable surrogates of diazo compounds, which participate in various reactions due to their versatile reactivity. Based on these characteristics, a strategy for C-N bond or C-C bond construction of aromatic amines with sulfoxonium ylides under metal-free catalytic conditions was established. This method has advantages of mild conditions and excellent yield, which is suitable for the N-H or C-H functionalization of various aromatic amine compounds.

Molecular docking and synthesis of N-alkyl-isatin-3-imino aromatic amine derivatives and their antileishmanial and cytotoxic activities.

Isatin derivatives have excited attention due to their biological attractions, especially, anticancer properties. Isatin analogs such as semaxanib and sunitinib were exposed to tyrosine kinase inhibitory properties. N-substituted isatins were reported to show cytotoxic activity. On the other, the extension of impressive and cost-effective agents against leishmaniasis is necessary in third-world countries. The capability of isatin derivatives to create novel anticancer and anti-leishmanial compounds has been identified in medicinal chemistry research. The current study aimed to synthesize N-alkyl-isatin-3-imino aromatic amine compounds and evaluate their biological effects. Synthesis started with the formation of 2-chloro-N-phenylacetamide derivatives by the reaction of aniline derivatives with chloroacetyl chloride. N-alkylation of isatin was performed in the presence of K2CO3 in N, N-dimethylformamide. Final products were prepared via the condensation of N-alkyl isatin derivatives with aromatic amines. Cell viability was checked out by using the MTT assay against cancer cells. Final compounds were screened for anti-leishmanial activity. The molecules were docked in the active sites of the epidermal growth factor receptor tyrosine kinase to define the possible interactions. Compounds 5c and 4d with IC50 value of 50 μΜ showed cytotoxic activity on the MCF-7 cell line. Compound 5b presented anti-leishmanial activity against promastigote form after 48 h (IC50:59 μΜ) and 72 h (IC50: 41 μΜ) incubations. The highest docking score was -7.33 kcal/mol for compound 4d. The nature of substitution in the N1 region of isatin seems to be able to influence the cytotoxic activity. Based on the obtained results of docking and cytotoxic tests, compound 4d seems to be a good compound for further investigations.

Exploring the surface plasmon catalytic reactions mechanism by three-phase interface modification combining with in-situ EC-SERS methods

Local surface plasmon resonance (LSPR) is a novel catalytic technique that has emerged in recent years, especially in the catalysis of aromatic amine compounds. However, the response process and mechanism are still unclear in current study. In the current field of study, the response process and mechanism are still unclear. In this work, the gas–liquid-solid three-phase interface (GLSTI) was innovatively utilized in this study to validate the reaction mechanism by surface-enhanced Raman spectroscopy. P-Aminothiophenol (PATP) and P-Phenylenediamine (PDA) underwent a surface plasmon-catalyzed reaction by using a silver nano-dendrites substrate with strong SERS activity. The GLSTI significantly facilitates the occurrence of surface plasmon catalytic reactions, which can supply enough oxygen by providing three-phase points. In situ SERS and EC-SERS technologies were combined in this study for the explorations. Therefore, this work is dedicated to deepening the exploration and expanding into new directions in plasmon-induced catalytic reactions.

Construction of supramolecular self-assembly of cyclobutanocucurbit[5]uril and six aromatic amines

Supramolecular self-assemblies are molecular aggregates formed by the combination of multiple molecules via intermolecular noncovalent bonding interactions. The synergy of hydrogen bonds and weak intermolecular interactions endows them with specific structures and functionalities. In this paper, 1H NMR spectroscopy, HPLC-QTOF mass spectrometry and other characterization methods were used to investigate the interaction modes of cyclobutanocucurbit[5]uril (CyB5Q[5]) and six aromatic amine compounds. The results showed that the negative electrostatic portal carbonyls of CyB5Q[5] interacted with the guest molecules via hydrogen bonding. The benzene ring in the guest molecules interacted with the methylene groups on the outer surface of CyB5Q[5] via CH···π interactions. [ZnCl4]2– anions acted as a structure-directing agent and participated in the ion-dipole interactions with the positive electrostatic outer surface of CyB5Q[5]. Three weak intermolecular interactions synergistically constructed a series of multi-level supramolecular self-assembly materials.

Eco-Friendly Degradation of Natural Rubber Powder Waste Using Some Microorganisms with Focus on Antioxidant and Antibacterial Activities of Biodegraded Rubber

Natural rubber (NR) powder wastes contribute to the pollution of the environment and pose a risk to human health. Therefore, Escherichia coli AY1 and Aspergillus oryzae were used to degrade NR in the present investigation. The biodegradation was further confirmed using E. coli AY1 and A. oryzae’s ability to create biofilm, which grew on the surface of the NR. Additionally, the biodegraded NR was examined by scanning electron microscopy (SEM), attenuated total reflection–Fourier transform infrared (ATR–FTIR) spectroscopy, and gas chromatography–mass spectrometry (GC–MS). The highest weight loss (69%) of NR was detected (p < 0.05) after 210 d of incubation with the mixed microbial culture (E. coli AY1 + A. oryzae). In the SEM, the surface of the control treatment appeared uniform and normal, whereas the surface of the microbial treatment displayed an irregular shape, with apparent particle deformation and surface erosion. After biodegradation by E. coli AY1 and A. oryzae, the particle size range of the untreated NR dropped from (5.367–9.623 µm) to (2.55–6.549 µm). After treating NR with E. coli AY1 and A. oryzae, new bands appeared in the ATR–FTIR technique; others shifted down in the range of 3910–450 cm−1, suggesting the existence of active groups belonging to alcohol, secondary amine, aromatic amine, conjugated anhydride, aldehyde, alkene, and halo compounds. On the other hand, the GC–MS profile reports a significant decline (p < 0.05) in the amount of hydrocarbons while simultaneously reporting a significant increase (p < 0.05) in the proportion of oxygenated, sulfurous, and nitrogenous compounds. These active groups are attributed to the antioxidant and antibacterial properties of biodegraded NR by a mixture of E. coli AY1 and A. oryzae, which rose 9-fold (p < 0.05) compared to untreated NR. Through the use of this research, we will be able to transform NR waste into a valuable product that possesses both antioxidant and antibacterial properties.

Urinary bio-monitoring of aromatic amine derivatives by new needle trap device packed with the multi-component adsorbent

Aromatic amines are a large group of chemical compounds that have attracted the attention of researchers due to their toxicity and carcinogenicity. This study aimed to develop an efficient method for sampling and analysis of aromatic amines (Aniline, N, N-dimethylaniline, 2-chloroaniline, and 3-chloroaniline) from the vapour phase (headspace) of urine samples. For the implementation of this plan, a needle trap device packed with the three-component adsorbent consisting of nano-Hydroxy Apatite (nHA), Zeolite (Ze), and Metal–Organic Framework (MOF) equipped with GC-FID was employed for the first phase. Examination of the prepared adsorbents was performed by FT-IR, PXRD, and FE-SEM techniques. The optimal value of considerable parameters such as time and temperature of extraction, salt content, and pH were established using the Response Surface Methodology-Central Composite Design (RMS-CCD) method. In this way, the optimal extraction of targeted analytes was accomplished in 41 min at 41 °C with NaCl content of 33.0% (w/v) and pH: 13.0, respectively. Also, the repeatability and reproducibility of the method were calculated to be in the range of 2.2–7.1% and 3.9–8.1%, respectively, which indicates the acceptable precision of the method. Also, the limit of detection (LOD) and limit of quantification (LOQ) were determined in the range of 0.3–32.0 ng.L−1 and 0.8–350.0 ng.L−1, respectively, which proves the high sensitivity of the proposed method. Furthermore, the recovery percent of the extracted analytes was concluded in the range of 97.0–99.0% after 6 and 30 days of the sampling and storage at 25 °C and 4 °C, respectively. Finally, the designed procedure was employed in the analysis of the above-mentioned aromatic amines in the real urine samples. The achieved results illustrate that the three-component absorbent system (nHA;Ze;MOF@NTD) can be introduced as an efficient, fast-response, sensitive, and versatile procedure for trace analysis of the different aromatic amine compounds in public and occupational health.

Tetra-n-butylammonium decatungstate supported on Fe3O4 nanoparticles: a novel nanocatalyst for green synthesis of nitroso compounds

The Fe3O4/TBADT composite catalyst (M-DT) can efficiently oxidize aromatic amine compounds selectively into nitroso compounds in the presence of H2O2. The high efficiency is due to the strong interaction between Fe3O4 and TBADT.

Cytotoxic Homo- and Hetero-Dimers of o-toluidine, o-anisidine, and Aniline Formed by In Vitro Metabolism.

Several aromatic amine compounds are urinary bladder carcinogens. Activated metabolites and DNA adducts of polycyclic aromatic amines, such as 4-aminobiphenyl, have been identified, whereas those of monocyclic aromatic amines, such as o-toluidine (o-Tol), o-anisidine (o-Ans), and aniline (Ani), have not been completely determined. We have recently reported that o-Tol and o-Ans are metabolically converted in vitro and in vivo to cytotoxic and mutagenic p-semidine-type dimers, namely 2-methyl-N4-(2-methylphenyl) benzene-1,4-diamine (MMBD) and 2-methoxy-N4-(2-methoxyphenyl) benzene-1,4-diamine (MxMxBD), respectively, suggesting their roles in urinary bladder carcinogenesis. In this study, we found that when o-Tol and o-Ans were incubated with S9 mix, MMBD and MxMxBD as well as two isomeric heterodimers, MMxBD and MxMBD, were formed. Therefore, any two of o-Tol, o-Ans, and Ani (10 mM each) were incubated with the S9 mix for up to 24 h and then subjected to LC-MS to investigate their metabolic kinetics. Metabolic conversions to all nine kinds of p-semidine-type homo- and hetero-dimers were observed, peaking at 6 h of incubation with the S9 mix; MxMxBD reached the peak at 6.1 ± 1.4 μM. Homo- and hetero-dimers containing the o-Ans moiety in the diamine structure showed a faster dimerization ratio, whereas levels of these dimers, such as MxMxBD, markedly declined with further incubation. Dimers containing o-Tol and Ani were relatively stable, even after incubation for 24 h. The electron-donating group of the o-Ans moiety may be involved in rapid metabolic conversion. In the cytotoxic assay, dimers with an o-Ans moiety in the diamine structure and MMBD showed approximately two- to four-fold higher cytotoxicity than other dimers in human bladder cancer T24 cells. These chemical and biological properties of homo- and hetero-dimers of monocyclic aromatic amines may be important when considering the combined exposure risk for bladder carcinogenesis.

Synthesis of an aromatic amine derived from biomass and its use as a feedstock for versatile epoxy thermoset

Innovative bio-based monomers and polymers are required as substitutes for limited fossil resources. Aromatic amines as an important class of chemicals are currently mostly formulated from petroleum. In this paper, a guaiacol derivative aromatic amine (5-aminoguaiacol) was designed and successfully synthesized, which was employed together with vanillin to build a high bio-based bisphenol compound. Following by glycidylation and cross-linking with 4,4′-diaminodiphenyl methane (DDM), we presented an epoxy resin network (GV-EP/DDM) bearing dynamic Schiff base bonds with high glass transition temperature of 220 °C, char yield (in N2 at 800 °C) of 44.9%, storage modulus at 30 °C of 3602 MPa, and Young’s modulus of 4489 MPa, which was 33 °C, 2.5-fold, 38% and 28% higher than those of bisphenol A epoxy resin, respectively. Furthermore, the introduction of Schiff base structure endowed the GV-EP/DDM system with shape memory, degradability, reprocessability at 230 °C under 10 MPa, as well as satisfactory antibacterial property. Notably, the higher crosslinking density made GV-EP/DDM have stronger acid resistance than the other epoxy resins with Schiff base bonds. This work provides a feasible toolbox for production of bio-based aromatic amine compounds, and a strategy to construct high performance and versatile bio-based polymer materials.

New and efficient magnetic nanocomposite extraction using multifunctional deep eutectic solvent based on ferrofluid and vortex assisted-liquid–liquid microextraction: Determining primary aromatic amines (PAAs) in tetra-packed fruit juices

In this work, a novel magnetic nanocomposite solvent (MNCS) based on ferrofluid and multifunctional deep eutectic solvent (MDES) was synthesized and applied in vortex assisted-liquid–liquid microextraction (VA-LLME). The ferrofluid has been composed from zirconium phosphate (modified magnetic graphene oxide) and tetrabutylammonium bromide-octanoic acid deep eutectic solvent (MGO/α-ZrP@TBAB-OA). This efficient method was employed to determine primary aromatic amines including aniline, 4-methoxyanniline, 4,4′-diaminodiphenylmethane, orthotoluidine, 2,6-dimethylaniline, 2-naphtylamine in tetra-packed juice samples. The proposed method showed the excellent extraction efficiency of PAAs according to strong interactions of new extraction solvent including electrostatic, π-π, and hydrogen bonding attractions. The found levels of PAAs are lower than the limit of quantifications (2.0 µg L−1). Therefore, the migration of PAAs from packaging to the juice samples is lower than permitted level (<10 µg kg−1). The results indicated high potential use of the offered method to analyze aromatic amine compounds in foodstuff and biologic samples in the future.

Determination the effects of pumpkin and rosehip seed oils on heterocyclic aromatic amine formation in meatballs by high‐performance liquid chromatography

Heterocyclic aromatic amine (HCA) compounds, which are formed by heat treatment in foods, have the potential to cause serious negative effects on human health (carcinogen) when consumed with food. The aim of this study was to examine the effect of pumpkin seed oil (PSO) and rosehip seed oil (RSO) on the formation of HCA compounds in beef meatballs cooked by using different cooking methods (pan frying and oven methods) and different temperatures (150°C, 200°C, and 250°C). 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 1-methyl-9Hpyrido[4,3-b]indole (harman), and 9H-pyrido[4,3b]indole (norharman) compounds were determined by high-performance liquid chromatography (HPLC). IQ, MeIQx, and 4,8-DiMeIQx were quantified with diode array detector. PhIP, norharman, and harman were quantified with fluorescence detector. In general, the total HCA formation was higher in the pan-cooked samples compared to the oven-baked samples, while an increase in HCA concentrations was determined with an increase in temperature. Although both oils had significant (p < .05) effects on HCA compounds compared to the control group, the inhibitory effect of PSO on HCA compounds was higher than RSO. With the addition of PSO and RSO at different concentrations (1% and 2%), HCA formation in meatballs could be inhibited by 19.95%–83.14% and 22.21%–77.23%, respectively. Practical applications In this study, pumpkin seed oil (PSO) and rosehip seed oil (RSO) were added to the meatballs in the ratio of 1% and 2% to show the effects of these extracts on heterocyclic aromatic amine (HCA) formation. Control and enriched samples were cooked at 150°C, 200°C, and 250°C in a pan and oven, and the effects of cooking method and also temperature on HCA amounts in meatball samples were evaluated. The formation of HCA compounds in meatballs, which is one of the most widely consumed meat products, could be inhibited significantly by the addition of 1% and 2% natural antioxidant PSO and RSO. The highest total HCA formation in meatball samples was obtained in the control samples (26.94 ng/g) cooked at 250°C. In general, the total HCA content of the meatballs cooked in the pan was higher than those cooked in the oven, and it was seen that the total HCA formation decreased as the oil content increased. PSO and RSO were effective natural antioxidants for inhibiting HCA formation. These natural antioxidants could be used for the enrichment of different cooked meat products for decreasing the formation of carcinogenic compounds such as HCAs. The obtained results could be used to estimate the human intake of HCAs and supplied to the search of good food additives that reduce the threat of exposure to HCAs, and thus to advance the food security and quality.

Interrogating the Behaviour of a Styryl Dye Interacting with a Mesoscopic 2D-MOF and Its Luminescent Vapochromic Sensing.

In this contribution, we report on the solid-state-photodynamical properties and further applications of a low dimensional composite material composed by the luminescent trans-4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) dye interacting with a two-dimensional-metal organic framework (2D-MOF), Al-ITQ-HB. Three different samples with increasing concentration of DCM are synthesized and characterized. The broad UV-visible absorption spectra of the DCM/Al-ITQ-HB composites reflect the presence of different species of DCM molecules (monomers and aggregates). In contrast, the emission spectra are narrower and exhibit a bathochromic shift upon increasing the DCM concentration, in agreeance with the formation of adsorbed aggregates. Time-resolved picosecond (ps)-experiments reveal multi-exponential behaviors of the excited composites, further confirming the heterogeneous nature of the samples. Remarkably, DCM/Al-ITQ-HB fluorescence is sensitive to vapors of electron donor aromatic amine compounds like aniline, methylaniline, and benzylamine due to a H-bonding-induced electron transfer (ET) process from the analyte to the surface-adsorbed DCM. These findings bring new insights on the photobehavior of a well-known dye when interacting with a 2D-MOF and its possible application in sensing aniline derivatives.

Study on the Feasibility of Enhancing the Biodegradation of Aniline Wastewater by Polyvinyl Alcohol-Sodium Alginate Gel Pellets Embedded Activated Sludge

Embedded pellets obtained by means of embedding activated sludge in polyvinyl alcohol—sodium alginate were successfully adapted in aniline wastewater degradation system. The results of shake flask experiment showed that the combination of sludge and embedded pellets had the best performance in degrading aniline, compared with sludge system and pellet system. Moreover, the application of embedded pellets promoted the toxicity tolerance and operation performance of the reactor. The enhanced reactor could completely degrade aniline and ammonia nitrogen in 150 and 240 min, and the total nitrogen removal rate increased by 26.83%. Meanwhile, high-throughput sequencing results illustrated that the addition of embedded pellets can effectively protect the diversity of functional microbial community. The average relative abundances of main functional genera such as Hydrogenophaga (aromatic amine compounds degradation and heterotrophic nitrification-aerobic denitrification), Norank_f__ Microscillaceae (nitrification), Brevundimonas (heterotrophic nitrification-aerobic denitrification), and Flavobacterium (denitrification) increased by 50.63%, 73.45%, 99.71%, 89.6%, 72.01%, and 95.70%, respectively.

Computational modeling of inclusion complex between aromatic amine and calixarene analogs using Semiempiric Quantum Method (SQM)

PM3 Semiempiric Quantum calculation has been done in this research by using Gaussian 2009 Rev. D 01 software package to explore the capability of Calixarene and its analogs for aromatic amine extraction. The Calixarene analogs used in this research are Calixpyrrole, Calixpyridine, Thiacalixarene, Heterocalixaromatic, Calixcarbazole and Calixnaphtalene; and the aromatic amine used in this research are Aniline, 4-Chloroaniline, Toluene-2,4-diamine, 2-Naphty lamině, 4,4’-Mety lenbis(2-chloroaniline), 4,4’-Metylendianiline, N-Nitrosodiphenylamine, Benzidine, 2-Aminobiphenyl, 2-Amino-1-methyl-6-phenylimidazo[4,5-b] Pyridine, 3-Trifluoromethylaniline, p-Phenylendiamine, o-Toluidin, 4-Chloro-o-toluidin. The most suitable host molecule of calixarene analogs for extraction of aromatic amine compounds are Calixnaphthalene and Calixpyridine because all of aromatic amine compounds form inclusion complex with them spontaneously shown by negative value of binding energy.

Molecular docking study of inclusion complex between aromatic amine and Calixarene analogs

A molecular docking was performed in this research by using ArgusLab version 4.0.1. It was used to explore the capability of Calixarene analogs for aromatic amine extraction. There are 6 Calixarene analogs used in this research, i.e. Calixpyrrole, Calixpyridine, Thiacalixarene, Heterocalixaromatic, Calixcarbazole and Calixnaphtalene; and the aromatic amine used in this research are Aniline, 4-Chloroaniline, Toluene-2,4-diamine, 2-Naphtylamine, 4,4’-Metylenbis(2-chloroaniline), 4,4’-Metylendianiline, N-Nitrosodiphenylamine, Benzidine, 2-Aminobiphenyl, 2-Amino-1-methyl-6-phenylimidazo [4,5-b] Pyridine, 3-Trifluoromethylaniline, p-Phenylendiamine, o-Toluidin, 4-Chloro-o-toluidin. In this molecular docking simulation, the guest molecule of aromatic amine compounds were treated as ligand and host molecule of calixarene and its analogs were treated as binding site. This molecular docking simulation used AScore scoring function, binding sitebox size for host molecule with grid size of 0.4 Å, GA docking engine with flexible ligand, 50 population sizes, 1000 max generations, 5 elitisms, 0.2 mutation rate, and 0.8 crossover rate. Calixcarbazole and Calixnaphthelene is the best host molecule for aromatic amines extraction because the inclusion complexes formed between them have negative value of binding energy.

Bioremediation of 2,4-Diaminotoluene in Aqueous Solution Enhanced by Lipopeptide Biosurfactant Production from Bacterial Strains

AbstractThis research concentrated on the isolation and preparation of biosurfactant-producing bacterial strains for the degradation of aromatic amine compound 2,4-diaminotoluene (2,4-DAT). Three s...

Efficient extraction of aromatic amines in the air by the needle trap device packed with the zirconium based metal-organic framework sorbent.

In this study, development of a needle trap device (NTD) packed with UiO-66 adsorbent was used for the sampling of the aromatic amine compounds (including aniline, N,N-dimethylaniline and o-toluidine) followed by gas chromatography (GC) with flame-ionization detector (FID) analysis. The UiO-66 sorbent was synthesized and then packed inside a spinal needle (Gauge 22). The synthesized sorbent was characterized with the XRD, FE-SEM, EDS and FT-IR techniques. This study was conducted both in the laboratory and in the real samples. In the laboratory, the sampling parameters (such as temperature and humidity) and desorption parameters (including desorption temperature and desorption time) were optimized using Response Surface Methodology (RSM) by Central Composite Design (CCD). The results indicated that the performance of the sampling device decreased with increasing the sampling humidity and temperature. Moreover, the highest peak area responses of the studied analytes were observed at a desorption time of 3 minutes and desorption temperature of 270 °C. The values of the limit of detection (LOD) and limit of quantitation (LOQ) were in the range 0.01–0.02 and 0.03–0.05 ng mL−1, respectively. Our findings demonstrated that NTD packed with synthesized UiO-66 has good repeatability (RSD = 1.3–6.8%) and acceptable reproducibility (with three NTDs) (RSD = 1.3–9.7%). Comparison of the results between NTD-UiO-66 and NIOSH2002 showed a sufficient correlation (0.98–0.99) between two methods. Therefore, the results indicated that the NTD packed with the UiO-66 adsorbent can be used as a powerful technique for occupational and environmental monitoring.

13C and 15N NMR identification of product compound classes from aqueous and solid phase photodegradation of 2,4,6-trinitrotoluene.

Photolysis is one of the main transformation pathways for 2,4,6-trinitrotoluene (TNT) released into the environment. Upon exposure to sunlight, TNT is known to undergo both oxidation and reduction reactions with release of nitrite, nitrate, and ammonium ions, followed by condensation reactions of the oxidation and reduction products. In this study, compound classes of transformation products from the aqueous and solid phase photodegradation of 2,4,6-trinitrotoluene (TNT) have been identified by liquid and solid state 13C and 15N NMR. Aqueous phase experiments were performed on saturated solutions of T15NT in deionized water, natural pond water (pH = 8.3, DOC = 3.0 mg/L), pH 8.0 buffer solution, and in the presence of Suwannee River Natural Organic Matter (SRNOM; pH = 3.7), using a Pyrex-filtered medium pressure mercury lamp. Natural sunlight irradiations were performed on TNT in the solid phase and dissolved in the pond water. In deionized water, carboxylic acid, aldehyde, aromatic amine, primary amide, azoxy, nitrosophenol, and azo compounds were formed. 15N NMR spectra exhibited major peaks centered at 128 to 138 ppm, which are in the range of phenylhydroxylamine and secondary amide nitrogens. The secondary amides are proposed to represent benzanilides, which would arise from photochemical rearrangement of nitrones formed from the condensation of benzaldehyde and phenylhydroxylamine derivatives of TNT. The same compound classes were formed from sunlight irradiation of TNT in the solid phase. Whereas carboxylic acids, aldehydes, aromatic amines, phenylhydroxylamines, and amides were also formed from irradiation of TNT in pond water and in pH 8 buffer solution, azoxy and azo compound formation was inhibited. Solid state 15N NMR spectra of photolysates from the lamp irradiation of unlabeled 2,6-dinitrotoluene in deionized water also demonstrated the formation of aromatic amine, phenylhydroxylamine/ 2° amide, azoxy, and azo nitrogens.

Synthesis, characterization and biological evaluation of some novel N-Mannich bases of heterocyclic 1,3,4-thiadiazole.

A series of some novel N-Mannich bases of heterocyclic 1,3,4-thiadiazole were synthesized through the condensation reaction of 1,3,4-thiadiazole containing a aromatic secondary amine, aromatic aldehydes and cyclic compounds employing Mannich reaction and using conventional synthesis. All the synthesized compounds were obtained in the range of 57.41-83.3 % yield. The structures of synthesized compounds were confirmed by UV, IR, 1H NMR spectroscopy. the essential structural features responsible for interaction with receptor site are established within a suggested pharmacophore. The in vitro antibacterial activity of the synthesized compounds was determined, against two Gram-positive bacteria, viz. S. aureus &amp; B. subtilis and Gram-negative, viz. E. coli and K. pneumoniae, by cup-plate method using the standard drug ciprofloxacin. Minimum inhibitory concentrations (MIC) changed in the range of 1.56_ _ 200 mg mL_1. Compound 3b exhibited excellent activity against both bacteria. The in vitro antifungal activity of the synthesized compound was also evaluated by cup-plate method against the fungi A. niger and C. albicans compared with the standard drug Fluconazole. Compound 4a, 8a exhibited excellent activity against both fungi. The result has shown that the compounds are quite active against pathogens under study and were nontoxic. The anti-inflammatory activity of the compound was evaluated, on albino rats, by carageenan induced rat paw oedema method using the standard drug diclofenac sodium. Compound 7b and 8c exhibited excellent anti-inflammatory and analgesic pharmacological activities. Structurally the compound 7b has a greater number of unsaturated hydrocarbons in schiff base, which shows good lipophilic properties within electron rich morpholine ring in Mannich base. Statistical significance of differences between group was determined by one-way analysis of variance (ANOVA). Among the synthesized compounds 3a, 4b, 5c, 7b, 8a and 8c were found be the most active. All the synthesized compounds were found to be low lethal as ascertained by LD50 test. Keywords: N- Mannich bases of heterocyclic 1,3,4-thiadiazole derivatives; Mannich reaction; antimicrobial agents; anti-inflammatory activity;

Red‐Shifted Absorption of C‐Dots for Utilization in Hybrid Nano‐Optoelectronics by Application of Systematically Synthesized Precursor Molecules

In this work, a facile, easy and scalable synthetic protocol is modified at the precursor level to shift absorption of the resulting carbon nanodots (C‐dots) to larger wavelengths. Using the knowledge about possible intermediates during the solvothermal pyrolysis for predictions of the final absorption of the products, several types of precursor variations from the original mixture of citric acid (CA) and polyethylenimine (PEI) are being tested. Syntheses over distinct steps of refined aromatic amine compounds with different size and number of functional groups are performed and the structures transferred into the pyrolysis protocol. UV–VIS measurements prove the success of the red‐shifted absorption of the resulting products and show limitations of the precursor‐vise tunability. Photoluminescence measurements are conducted with the most promising example of each optimization category to prove a correlation between absorption and luminescence behavior. 1H DOSY NMR experiments are used for size comparison between the particles in solution to check for an impact between particle size and absorption. Optimized, tailor‐made C‐dots are tested as light‐harvesters for application in hybrid nanodevices in combination with ZnO nanowire arrays. The photoconductivity can be increased tremendously in wavelengths above the semiconductor band gap using the tuned C‐dots as photosensitizers.