Design, Synthesis, and Fungicidal Activities of Novel N-(Pyrazol-5-yl)benzamide Derivatives Containing a Diphenylamine Moiety

To accelerate the development of novel fungicides, a variety of N-(pyrazol-5-yl)benzamide derivatives with a diphenylamine moiety were designed and synthesized using a pharmacophore recombination strategy based on the structure of pyrazol-5-yl-aminophenyl-benzamides. The bioassay results demonstrated that most of the target compounds had excellent in vitro antifungal activities against Sclerotinia sclerotiorum, Valsa mali, and Botrytis cinerea. In particular, compound 5IIIh exhibited remarkable activity against S. sclerotiorum (EC50 = 0.37 mg/L), which was similar to that of fluxapyroxad (EC50 = 0.27 mg/L). In addition, compound 5IIIc (EC50 = 1.32 mg/L) was observed to be more effective against V. mali than fluxapyroxad (EC50 = 12.8 mg/L) and comparable to trifloxystrobin (EC50 = 1.62 mg/L). Furthermore, compound 5IIIh demonstrated remarkable in vivo protective antifungal properties against S. sclerotiorum, with an inhibition rate of 96.8% at 100 mg/L, which was close to that of fluxapyroxad (99.6%). Compounds 5IIIc (66.7%) and 5IIIh (62.9%) exhibited good in vivo antifungal effects against V. mali at 100 mg/L, which were superior to that of fluxapyroxad (11.1%) but lower than that of trifloxystrobin (88.9%). The succinate dehydrogenase (SDH) enzymatic inhibition assay was conducted to confirm the mechanism of action. Molecular docking analysis further revealed that compound 5IIIh has significant hydrogen-bonding, π-π, and p-π conjugation interactions with ARG 43, SER 39, TRP 173, and TYR 58 in the binding site of SDH, and the binding mode was similar to that of the commercial fungicide fluxapyroxad. All of the results suggest that compound 5IIIh could be a potential SDH inhibitor, offering a valuable reference for future studies.

Synthesis and In Vitro Evaluation as Potential Anticancer and Antioxidant Agents of Diphenylamine-Pyrrolidin-2-one-Hydrazone Derivatives

The title compounds were synthesized by the reaction of 5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide with various aldehydes bearing aromatic and heterocyclic moieties and acetophenones, and their cytotoxicity was tested via MTT assay against human triple-negative breast cancer MDA-MB-231, human melanoma IGR39, human pancreatic carcinoma Panc-1, and prostate cancer cell line PPC-1. Furthermore, the selectivity of compounds towards cancer cells compared to fibroblasts was also investigated. Four compounds were identified as the most promising anticancer agents out of a series of pyrrolidinone-hydrazone derivatives bearing a diphenylamine moiety. These compounds were most selective against the prostate cancer cell line PPC-1 and the melanoma cell lines IGR39, with EC50 values in the range of 2.5-20.2 µM against these cell lines. In general, the compounds were less active against triple-negative breast cancer MDA-MB-231 cell line, and none of them showed an inhibitory effect on the migration of these cells. In the 'wound healing' assay, N'-((5-nitrothiophen-2-yl)methylene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide was identified as the most promising derivative that could be further developed as an antimetastatic agent. N'-(5-chloro- and N'-(3,4-dichlorobenzylidene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazides most efficiently reduced the cell viability in IGR39 cell spheroids, while there was no effect of the investigated pyrrolidinone-hydrazone derivatives on PPC-1 3D cell cultures. Antioxidant activity determined via FRAP assay of N'-(1-(4-aminophenyl)ethylidene)-5-oxo-1-(4-(phenylamino)phenyl)pyrrolidine-3-carbohydrazide was 1.2 times higher than that of protocatechuic acid.

Iron overload induced by diphenylamine triggers reactive oxygen species and apoptosis in the spleen of pregnant rats and their fetuses

Diphenylamine (DPA) is an aniline derivative, used widely as an industrial antioxidant, dye mordant, and agricultural fungicide. DPA was reported as hazardous to mammals both acutely and chronically, however little is known about the toxicity of DPA and its derivatives during pregnancy. This study aimed to evaluate and explain the possible mechanism of toxicity induced by DPA on blood and spleen, as a fundamental hematopoietic target organ, in pregnant rats and their fetuses. Pregnant rats were orally administrated distilled water, corn oil, and/or DPA (400 mg/kg b.wt) from the 5th to 19th day of gestation. DPA-induced spleen toxicity was mirrored by significant upregulation of programmed death-1 (PD-1) protein expression and an increase in the percentage of apoptotic cells and a decrease in their proliferating capacity. These results have been confirmed through marked G0/G1 cell-cycle arrest that was observed by flow cytometric analysis of spleen cells. Moreover, the contents of reactive oxygen species and iron in the spleen tissue were significantly higher than that of the control group. DPA resulted in severe anemia, decreased hemoglobin and hematocrit, thrombocytopenia and leukopenia in addition to significant changes in differential leukocytic count of both mothers and fetuses. Evidently, DPA triggered serious pathological changes in the spleen tissue of both mothers and fetuses and the histochemical examination revealed a significant increase in iron expression. In conclusion, these results implicate the hemato- and splenotoxicity of DPA and the possible role of oxidative stress and apoptosis in DPA-induced toxicity in the spleen of pregnant rats and their fetuses. This in-turn suggests the urgent need to reduce exposure to DPA as possible as it can.

Efficient D-π-π-A-Type Dye Sensitizer Based on a Benzothiadiazole Moiety: A Computational Study

The design of highly efficient sensitizers is one of the most significant areas in dye-sensitized solar cell (DSSC) research. We studied a series of benzothiadiazole-based D-π-π-A organic dyes, putting emphasis on the influence of the donor moiety on the DSSC's efficiency. Using (linear-response time-dependent) density functional theory ((TD)DFT)) with the CAM-B3LYP functional, different donor groups were characterized in terms of electronic absorption spectra and key photovoltaic parameters. As a reference, a dye was considered that had a benzothiadiazole fragment linked via thiophene rings to a diphenylamine donor and a cyanoacrylic-acid acceptor. The different systems were first studied in terms of individual performance parameters, which eventually aggregated into power conversion efficiency. Only the amino-substituted species showed a modest increase, whereas the dimethylamino case showed a decrease.

GC-MS Analysis of Methadone and EDDP in Addicted Patients under Methadone Substitution Treatment: Comparison of Urine and Plasma as Biological Samples

(1) Background: Methadone, along with buprenorphine, is the most commonly used drug for the treatment of opioid dependence. This study aimed to analyze methadone and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenyl pyrrolidine (EDDP), in the urine and plasma of opiate addicts. The study group consisted of drug users voluntarily admitted to the detoxification center C.E.T.T.T. "St. Stelian" of Bucharest. Secondly, the study aimed to identify whether urine or plasma provides better results for the proposed method. (2) Methods: A GC-MS method, using an internal standard (diphenylamine) in the FULL-SCAN and SIM modes of operation and using the m/z = 72 ion for methadone and the m/z = 277 ion for EDDP, combined with a liquid-liquid extraction procedure was performed. (3) Results: The applied procedure allows the detection and quantification of methadone in both urine and plasma samples. EDDP was identified in patients with higher levels of methadone. Higher levels of methadone were detected in urine than in plasma samples. (4) Conclusions: This procedure can be used in clinical laboratories for the rapid determination of methadone levels in urine rather than in plasma. The procedure can be applied for the monitoring of methadone substitution treatment.

The Photoluminescence and Vibrational Properties of Black Phosphorous Sheets Chemically/Electrochemically Functionalized in the Presence of Diphenylamine

In this work, new information concerning the optical properties of black phosphorus (BP) sheets chemically/electrochemically functionalized with diphenyl amine (DPA) and its macromolecular compound (poly(diphenylamine) (PDPA)) in the absence/presence of phosphotungstic acid (PTA) is reported. Raman scattering and FTIR spectroscopy studies indicate that the interaction of BP with PTA leads to the elimination of the P_xO_y layer onto the surface of the BP sheets. In the case of the chemical interaction of BP with DPA, the reaction product corresponds to DPA chemically functionalized BP sheets having an imino-phosphorane (IP) structure. The electrochemical oxidation of BP sheets chemically functionalized with DPA in the presence of PTA leads to an increase in the weight of P-N bonds as a consequence of the generation of PDPA doped with the PTA heteropolyanions, as shown by FTIR spectroscopy and Raman scattering. This process is evidenced by a shift of the Raman line from 362 cm^-1 to 378 cm^-1, assigned to the A_1g mode. This change was explained by taking into account the compression of the layers containing P atoms, which is induced by PDPA macromolecular chains. The decrease in the intensity of the PL spectra of DPA as well as PDPA, in the presence of BP, indicates that BP acts as a PL quenching agent for these compounds. A preferential orientation of the PDPA doped with the PTA heteropolyanions on the surface of BP sheets is highlighted by the variation of the binding angle of the PDPA on the surface of BP sheets from 44.7° to 39.9°.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted liquid-liquid micro-extraction combined with HPLC-FLD for diphenylamine determination in fruit

In this paper, novel high extraction efficiency hydrophobic eutectic solvents (DESs), n-octanoic acid as a hydrogen bond donor (HBD) and menthol as a hydrogen bond acceptor (HBA), were selected from five hydrophobic DESs to extract trace diphenylamine (DPA) in fruits apple, pear and orange under ultrasonic-assisted liquid-liquid micro-extraction (UA-LLME) technology before high-performance liquid chromatography (HPLC) analysis. Working parameters such as the DESs type, molar ratio, extractant volume, and ultrasonic time of the LLME hydrophobic DESs technology were optimised. Average recoveries between 96% and 108% were obtained on actual samples. This method gave lower detection limit (LOD) than other existing methods due to combining the high-efficiency extraction of hydrophobic DES and high sensitivity of fluorescence detector. This method was sensitive and eco-friendly, and can be used for the determination of trace components in fruits.

Strategies to Preserve Postharvest Quality of Horticultural Crops and Superficial Scald Control: From Diphenylamine Antioxidant Usage to More Recent Approaches

Horticultural crops are vulnerable to several disorders, which affect their physiological and organoleptic quality. For about forty years, the control of physiological disorders (such as superficial scald) in horticultural crops, particularly in fruit, was achieved through the application of the antioxidant diphenylamine (DPA), usually combined with controlled atmosphere (CA) conditions. However, identification of DPA residues and metabolites in treated fruits, associated with their toxicity, banned the use of this antioxidant in Europe. This triggered the urgent need for novel and, ideally, natural and sustainable alternatives, combined with adequate storage conditions to protect cultivars from harmful agents. This review systematizes the state-of-the-art DPA application on several fresh cultivars, such as apples, pears, and vegetables (potatoes, spinach, etc.), as well as the possible mechanisms of the action and effects of DPA, emphasizing its antioxidant properties. Alternative methods to DPA are also discussed, as well as respective effects and limitations. Recent research on scald development molecular pathways are highlighted to open new non-chemical strategies opportunities. This appraisal shows that most of the current solutions have not lead to satisfactory commercial results; thus, further research aimed to understand the mechanisms underlying postharvest disorders and to design sustainable and safe solutions to improve horticultural products storage is needed.

An Electrochemical Sensor for Diphenylamine Detection Based on Reduced Graphene Oxide/Fe₃O₄-Molecularly Imprinted Polymer with 1,4-Butanediyl-3,3'-bis-l-vinylimidazolium Dihexafluorophosphate Ionic Liquid as Cross-Linker

In this paper, we report a new composite of reduced graphene oxide/Fe₃O₄-ionic liquid based molecularly imprinted polymer (RGO/Fe₃O₄-IL-MIP) fabricated for diphenylamine (DPA) detection. RGO/Fe₃O₄-IL-MIP was prepared with RGO/Fe₃O₄ as supporter, ionic liquid 1-vinyl-3-butylimidazolium hexafluorophosphate ([VC₄mim][PF₆]) as functional monomer, ionic liquid 1,4-butanediyl-3,3'-bis-l-vinylimidazolium dihexafluorophosphate ([V₂C₄(mim)₂][(PF₆)₂]) as cross-linker, and diphenylamine (DPA) as template molecule. Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and vibrating sample magnetometer were employed to characterize the RGO/Fe₃O₄-IL-MIP composite. RGO/Fe₃O₄-IL-MIP was then drop-cast onto a glassy carbon electrode to construct an electrochemical sensor for DPA. The differential pulse voltammetry (DPV) peak current response for 20 μM DPA of RGO/Fe₃O₄-IL-MIP modified glassy carbon electrode (GCE) was 3.24 and 1.68 times that of RGO/Fe₃O₄-IL-NIP and RGO/Fe₃O₄-EGDMA-MIP modified GCEs, respectively, indicating the advantage of RGO/Fe₃O₄-IL-MIP based on ionic liquid (IL) as a cross-linker. The RGO/Fe₃O₄-IL-MIP sensor demonstrated good recognition for DPA. Under the optimized conditions, the RGO/Fe₃O₄-IL-MIP sensor exhibited a DPA detection limit of 0.05 μM (S/N = 3) with a linear range of 0.1⁻30 μM. Moreover, the new RGO/Fe₃O₄-IL-MIP based sensor detected DPA in real samples with satisfactory results.

AIE-Active Polyamide Containing Diphenylamine-TPE Moiety with Superior Electrofluorochromic Performance

Electrofluorochromism has attracted great attention due to the intelligence optoelectronic and sensing applications. The intrinsically switchable fluorophores with high solid-state fluorescence are regarded as key for ideal electrofluorochromic materials. Here, we reported an AIE-active polyamide with diphenylamine and tetraphenylethylene units, showing high fluorescence quantum yield up to 69.1% for the solid polymer film and stable electrochemical cycling stability. The polyamide exhibited reversible color and emission switching even in hundreds of cycles, and the fluorescence on/off contrast ratio was determined up to 417, which is the highest value to our knowledge. Furthermore, as the response time is vital for the real-life applications, to speed up the response of electrofluorochromism, a porous polymer film was readily prepared through a facile method, notably exhibiting high fluorescence contrast, long-term stability and obviously improved response, due to the sharply increased surface area. Therefore, the AIE-functionalization combining the porous structure strategy will synergistically and dramatically improve the electrofluorochromic performance, which will also promote their practical applications in the near future.

Metabolic and Evolutionary Insights in the Transformation of Diphenylamine by a Pseudomonas putida Strain Unravelled by Genomic, Proteomic, and Transcription Analysis

Diphenylamine (DPA) is a common soil and water contaminant. A Pseudomonas putida strain, recently isolated from a wastewater disposal site, was efficient in degrading DPA. Thorough knowledge of the metabolic capacity, genetic stability and physiology of bacteria during biodegradation of pollutants is essential for their future industrial exploitation. We employed genomic, proteomic, transcription analyses and plasmid curing to (i) identify the genetic network of P. putida driving the microbial transformation of DPA and explore its evolution and origin and (ii) investigate the physiological response of bacterial cells during degradation of DPA. Genomic analysis identified (i) two operons encoding a biphenyl (bph) and an aniline (tdn) dioxygenase, both flanked by transposases and (ii) two operons and several scattered genes encoding the ortho-cleavage of catechol. Proteomics identified 11 putative catabolic proteins, all but BphA1 up-regulated in DPA- and aniline-growing cells, and showed that the bacterium mobilized cellular mechanisms to cope with oxidative stress, probably induced by DPA and its derivatives. Transcription analysis verified the role of the selected genes/operons in the metabolic pathway: DPA was initially transformed to aniline and catechol by a biphenyl dioxygenase (DPA-dioxygenase); aniline was then transformed to catechol which was further metabolized via the ortho-cleavage pathway. Plasmid curing of P. putida resulted in loss of the DPA and aniline dioxygenase genes and the corresponding degradation capacities. Overall our findings provide novel insights into the evolution of the DPA degradation pathway and suggests that the degradation capacity of P. putida was acquired through recruitment of the bph and tdn operons via horizontal gene transfer.

Synthesis and antimicrobial activity of some new diphenylamine derivatives

In search of new leads toward potent antimicrobial agent, an array of novel derivatives of 2-hydrazinyl–N-N, diphenyl acetamide has been synthesized from the chloroacetylation reaction of diphenylamine (DPA). For this, a series of DPA derivatives were prepared by replacing chlorine with hydrazine hydrate in alcoholic medium and 2-hydrazino-N, N-diphenylacetamide was synthesized. The 2-hydrazino-N, N-diphenylacetamide was further subjected to reaction with various aromatic aldehydes in presence of glacial acetic acid in methanol. The synthesized compounds were characterized by their IR, 1HNMR spectral data and elemental analysis. The compounds were screened for antibacterial and antifungal activity by cup plate method. 2-(2-Benzylidenehydrazinyl)-N, N-diphenylacetamide (A1); 2-(2-(3-methylbenzylidene) hydrazinyl)-N, N-diphenyl-acetamide (A5) and 2-(2-(2-nitrobenzylidine) hydrazinyl)-N, N-diphenyl-acetamide compounds (A7) showed significant antimicrobial as well as antifungal activity. Diphenylamine compounds may be explored as potent antimicrobial and antifungal compounds.

Kinesin spindle protein inhibitors with diaryl amine scaffolds: crystal packing analysis for improved aqueous solubility

Diaryl amine derivatives have been designed and synthesized as novel kinesin spindle protein (KSP) inhibitors based on planar carbazole-type KSP inhibitors with poor aqueous solubility. The new generation of inhibitors was found to show comparable inhibitory activity and high selectivity for KSP, and this was accompanied with improved solubility. Kinetic analysis and molecular modeling studies suggested that these inhibitors work in an ATP-competitive manner via binding to the secondary allosteric site formed by α4 and α6 helices of KSP. Comparative structural investigations on a series of compounds revealed that the higher solubility of diaryl amine-type inhibitors was attributed to fewer van der Waals interactions in the crystal packing and the hydrogen-bond acceptor nitrogen of the aniline moiety for favorable solvation.