16635-14-6Relevant academic research and scientific papers
Crystal structure analysis and quantum chemical study of two macrocyclic compounds
Maragatham,Prabhakaran,Rajakumar,Lakshmi
, (2020)
The synthesis of new organic macrocyclic nonlinear optical materials with good performance has taken the prime focus of research due to the unlimited design possibilities. Two macrocyclic structures, confirmed by 1H, 13C NMR and FT-IR, namely spiro pyrrolidine grafted methyl macrocycle C28H26N2O3 and 1,2,3 triazole bridged pyrrolidine grafted chloro macrocycle C29H27Cl1N4O30.5(H2O) are analysed by single crystal X-ray diffraction method. The UV–Vis spectra of the two compounds show that these crystals are transparent in the entire visible region. The global reactivity descriptors such as ionization potential, electron affinity, electronegativity, chemical hardness, chemical potential, chemical softness, electrophilicity index and nonlinear optical parameters such as dipole moment (μ) and static second order hyperpolarizability (γ) are determined in gas phase at the molecular level by semiempirical quantum chemical method with the coordinates obtained from X-ray diffraction as the starting geometry. In addition, the bioactivity scores were calculated from the chemical skeleton.
Water stable fluorescent organotin(iv) compounds: aggregation induced emission enhancement and recognition of lead ions in an aqueous system
Capalash, Neena,Kaur, Kulwinder,Kaur, Varinder,Singh, Raghubir
, p. 148 - 161 (2021/12/31)
Herein, synthesis, spectroscopic studies, single-crystal X-ray diffraction, aggregation-induced emission enhancement (AIEE) and sensing application of water-stable organotin(iv) compounds (4a-6aand4b-6b) obtained from 3-hydroxy-4H-chromen-4-one ligands are reported. All the synthesized organotin(iv) compounds were characterized using elemental analysis, FT-IR spectroscopy, multi-nuclei NMR (1H,13C, and119Sn) spectroscopy, UV-VIS, fluorescence spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The119Sn NMR signal of compounds in the range ofδ?144.92 to ?190.68 ppm indicated the formation of hexacoordinated organotin species. The spectroscopic and single-crystal X-ray diffraction studies confirmed the formation of [L2SnR2] type compounds (where L is the bidentate ligand and R is an alkyl group) with a ‘skew-trapezoidal bipyramidal’ geometry. Furthermore, DFT calculations of compound4bbased on the DGDZVP basis set fully supported the stability of the structure where two short bonds Sn-O(C-O)acquire thecisposition rather than thetransposition. Single-crystal X-ray diffraction analysis of the crystals grown in the presence of water confirmed the stability of4ain water. Moreover, the water stability of a test compound4awas established by119Sn NMR data and spectrofluorimetric data. The spectrofluorimetric scan at different time intervals revealed the stability and constant emission response up to 24 h. The compounds were found to be fluorescent and exhibited aggregation-induced emission enhancement in MeOH/H2O mixtures, which was confirmed by HRTEM analysis. The test compound4ashowed selective spectrofluorimetric recognition of Pb2+ions in an aqueous medium by displaying an enhanced emission signal at 478 nm and enabled detection up to 22.66 μM. A mechanism of interaction is also proposed by spectroscopic experiments, spectrofluorimetric experiments and computational studies.
Flavone-based hydrazones as new tyrosinase inhibitors: Synthetic imines with emerging biological potential, SAR, molecular docking and drug-likeness studies
Alsantali, Reem?I.,Mughal, Ehsan?Ullah,Naeem, Nafeesa,Alsharif, Meshari?A.,Sadiq, Amina,Ali, Anser,Jassas, Rabab.?S.,Javed, Qamar,Javid, Asif,Sumrra, Sajjad Hussain,Alsimaree, Abdulrahman?A.,Zafar, Muhammad?Naveed,Asghar, Basim?H.,Altass, Hatem?M.,Moussa, Ziad,Ahmed, Saleh?A.
, (2021/11/30)
Targeting tyrosinase (TYR), a key enzyme responsible for melanogenesis disorders, is a well-known approach utilized for the development of melanogenesis inhibitor. A variety of dermatological disorders and microbial skin infections can cause hyperpigmentation. Hence, exploring new scaffolds for the treatment of melanogenesis disease is an inspiring goal. In this context, a series of varyingly substituted flavone-based hydrazones have been designed, synthesized and characterized successfully. The present study describes the discovery of novel mushroom tyrosinase inhibitors (TIs) for treating hyperpigmentation. In due course, flavone scaffold has been incorporated into the novel chemotypes that exhibit in vitro inhibitory effects against mushroom tyrosinase for the purpose of discovering anti‐melanogenic agents. Biological investigations of prepared analogs herein demonstrated moderate to excellent activity against most of the fungal-bacterial strains and their activity is comparable to those of commercially available antibiotics i.e., Ciprofloxacin and Ketoconazole. Based on in vitro tyrosinase inhibitory assay, some compounds exhibited potent inhibition particularly, 3g (IC50 = 1.40 ± 0.16 μM), 3j (IC50 = 0.95 ± 0.07 μM), 3o (IC50 = 1.13 ± 0.11 μM), and 3q (IC50 = 1.01 ± 0.1 μM) showed best inhibition i.e., 0.7, 0.5, 0.6 and 0.5 folds, respectively, than kojic acid (IC50 = 1.79 ± 0.6 μM). Lineweaver-Burk plots demonstrated that the most potential derivative 3j tyrosinase inhibition proceeds via non-competitive pathway and the Michaelis-Menton constant (Km) value is 0.0265. Molecular modeling was performed for all tested analogs (3a–3q) using a model of mushroom tyrosinase to find crucial binding modes liable for inhibitory activity. The SARs were preliminarily examined, and the docking study revealed that analogs 3j, 3o and 3p had a strong binding association to tyrosinase (2Y9X). Furthermore, a drug-likeness study was employed and confirmed the favorable activity of the new analogs as a new anti-tyrosinase agent.
Mycobactin Analogues with Excellent Pharmacokinetic Profile Demonstrate Potent Antitubercular Specific Activity and Exceptional Efflux Pump Inhibition
Shyam, Mousumi,Verma, Harshita,Bhattacharje, Gourab,Mukherjee, Piyali,Singh, Samsher,Kamilya, Sujit,Jalani, Pushpendu,Das, Swetarka,Dasgupta, Arunava,Mondal, Abhishake,Das, Amit Kumar,Singh, Amit,Brucoli, Federico,Bagnéris, Claire,Dickman, Rachael,Basavanakatti, Vinay N.,Naresh Babu, Patibandla,Sankaran, Vadivelan,Dev, Abhimanyu,Sinha, Barij Nayan,Bhakta, Sanjib,Jayaprakash, Venkatesan
, p. 234 - 256 (2022/01/20)
In this study, we have designed and synthesized pyrazoline analogues that partially mimic the structure of mycobactin, to address the requirement of novel therapeutics to tackle the emerging global challenge of antimicrobial resistance (AMR). Our investigation resulted in the identification of novel lead compounds 44 and 49 as potential mycobactin biosynthesis inhibitors against mycobacteria. Moreover, candidates efficiently eradicated intracellularly surviving mycobacteria. Thermofluorimetric analysis and molecular dynamics simulations suggested that compounds 44 and 49 bind to salicyl-AMP ligase (MbtA), a key enzyme in the mycobactin biosynthetic pathway. To the best of our knowledge, these are the first rationally designed mycobactin inhibitors to demonstrate an excellent in vivo pharmacokinetic profile. In addition, these compounds also exhibited more potent whole-cell efflux pump inhibition than known efflux pump inhibitors verapamil and chlorpromazine. Results from this study pave the way for the development of 3-(2-hydroxyphenyl)-5-(aryl)-pyrazolines as a new weapon against superbug-associated AMR challenges.
Exploring 3-hydroxyflavone scaffolds as mushroom tyrosinase inhibitors: synthesis, X-ray crystallography, antimicrobial, fluorescence behaviour, structure-activity relationship and molecular modelling studies
Ashraf, Jamshaid,Mughal, Ehsan Ullah,Sadiq, Amina,Bibi, Maryam,Naeem, Nafeesa,Ali, Anser,Massadaq, Anam,Fatima, Nighat,Javid, Asif,Zafar, Muhammad Naveed,Khan, Bilal Ahmad,Nazar, Muhammad Faizan,Mumtaz, Amara,Tahir, Muhammad Nawaz,Mirzaei, Masoud
, p. 7107 - 7122 (2020/08/21)
To explore new scaffolds as tyrosinase enzyme inhibitors remain an interesting goal in the drug discovery and development. In due course and our approach to synthesize bioactive compounds, a series of varyingly substituted 3-hydroxyflavone derivatives (1-23) were synthesized in one-pot reaction and screened for in?vitro against mushroom tyrosinase enzyme. The structures of newly synthesized compounds were unambiguously corroborated by usual spectroscopic techniques (FTIR, UV-Vis, 1H-, 13C-NMR) and mass spectrometry (EI-MS). The structure of compound 15 was also characterized by X-ray diffraction analysis. Furthermore, the synthesized compounds (1-23) were evaluated for their antimicrobial potential. Biological studies exhibit pretty good activity against most of the bacterial-fungal strains and their activity is comparable to those of commercially available antibiotics i.e. Cefixime and Clotrimazole. Amongst the series, the compounds 2, 4, 5, 6, 7, 10, 11, 14 and 22 exhibited excellent inhibitory activity against tyrosinase, even better than standard compound. Remarkably, the compound 2 (IC50 = 0.280 ± 0.010 μg/ml) was found almost sixfold and derivative 5 (IC50 = 0.230 ± 0.020 μg/ml) about sevenfold more active as compared to standard Kojic acid (IC50 =1.79 ± 0.6 μg/ml). Moreover, these synthetic compounds (1-23) displayed good to moderate activities against tested bacterial and fungal strains. Their emission behavior was also investigated in order to know their potential as fluorescent probes. The molecular modelling simulations were also performed to explore their binding interactions with active sites of the tyrosinase enzyme. Limited structure-activity relationship was established to design and develop new tyrosinase inhibitors by employing 2-arylchromone as a structural core in the future. Communicated by Ramaswamy H. Sarma.
Synthesis, spectral and sol-gel behavior of mixed ligand complexes of titanium(iv) with oxygen, nitrogen and sulfur donor ligands
Srivastava, Abhishek,Srivastava, Neetu,Tripathi, Umesh Nath
, p. 61 - 76 (2021/06/03)
A new route to synthesize nano-sized Ti(IV) mixed ligand complexes have been investigated by the reaction of titanium(IV) chloride with ammonium salts of dithiophosphate and 3(2'-hydroxyphenyl)-5-(4- substituted phenyl) pyrazolines. The resultant complex is then treated with H2S gas to get sulfur bridged dimer of Ti(IV) complex, a precursor of TiS2. The morphology of the complexes was studied by employing XRD which shows that all the complexes are amorphous solid. Molecular weight measurements, elemental analysis in conjugation with spectroscopic (IR, 1H NMR, 13C NMR and 31P NMR) studies revealed the dimeric nature of the complexes in which pyrazoline and dithiophosphate are bidentate. Scanning electron microscopic image and XRD indicate that the particles are in the nano range (50 nm). Putting all the facts together, coordination number six is proposed for titanium with octahedral geometry.
Experimental and theoretical insights into the photophysical and electrochemical properties of flavone-based hydrazones
Ahmed, Ishtiaq,Ahmed, Safeer,Ahmed, Saleh A.,Alsantali, Reem I.,Alsharif, Meshari A.,Altaf, Ataf Ali,Altass, Hatem M.,Jassas, Rabab. S.,Kausar, Samia,Mughal, Ehsan Ullah,Mumtaz, Amara,Naeem, Nafeesa,Obaid, Rami J.,Sadiq, Amina,Zafar, Muhammad Naveed
, (2021/07/06)
A small library of flavone-based hydrazones has been designed, synthesized and characterized. In this context, thirteen flavone hydrazones (3a-3 m) were synthesized by the acid-catalyzed condensation of flavone with 2,4-dinitrophenylhydrazine (2,4-DNPH) and characterized by different spectral techniques (IR, UV–Vis, NMR and mass spectrometry). The electrochemical, photophysical and theoretical investigations of such type of compounds are hitherto unknown. The electrochemical behavior of these hydrazones at a platinum electrode has been analyzed by cyclic voltammetry (CV) and was investigated at 200, 100 and 40 mVs?1 in acetonitrile (CH3CN). These hydrazones showed a quasi-reversible redox reaction. The oxidation–reduction reactive sites of these derivatives were located via geometry optimization using density functional theory (DFT) at the B3LYP/3–21 g in the Guassian-09 level of theory. Moreover, the target compounds exhibited interesting fluorescent properties. Owing to their excellent photophysical and redox results, a detailed structure-property relationship was established to assess the substituents impact and their position on the physicochemical and electronic properties. All the experimental results were in accordance with the computational studies.
Synthesis and kinetic study for the interconversion process of some 2'-hydroxychalcones to their corresponding flavanones
Majed, Zainab Waleed,Said, Said Abdelqader,Shareef, Omar Adil
, p. 4379 - 4386 (2020/12/09)
In this work, five substituted2'-Hydroxychalconeswere prepared using Claisen - Schmidt condensation and used as a synthone for substituted flavanones via base catalyzed isomerization process. The latter process has been studied kinetically using HPLC technique in (8:2) (CH3CN:CH3OH) medium at different temperatures (298 K - 318 K). The obtained results were inconsonance with a four-step mechanism which considered the existence of phenoxide ion as the key intermediate. The reaction was achieved as a pseudo first order reaction in which the rate of the studied compounds followed the sequence 1>2>3>4>5, and the activation energy had the same sequence for these compounds. The reaction rate was affected by the electronic behavior of the different substituents at ring B since they played an important role in the stability of the intermediate that led to the final product.
Chiral Hydroxytetraphenylene-Boron Complex Catalyzed Asymmetric Diels-Alder Cycloaddition of 2′-Hydroxychalcones
Chai, Guo-Li,Qiao, Yan,Zhang, Ping,Guo, Rong,Wang, Juan,Chang, Junbiao
supporting information, p. 8023 - 8027 (2020/11/02)
(S)-2,15-Cl2-DHTP-boron complex catalyst for the asymmetric Diels-Alder cycloaddition of 2′-hydroxychalcones and dienes was developed and tested. The resulting cyclohexenes with three chiral centers were obtained in high yields (up to 98%) with excellent stereoselectivities (up to >20:1 endo/exo, >99% ee). This catalytic system features high efficiency, broad substrate scopes, and mild reaction conditions. In addition, a DFT study was performed to explain the stereochemical course of the asymmetric induction.
Temperature-Controlled Stereodivergent Synthesis of 2,2′-Biflavanones Promoted by Samarium Diiodide
Soto, Martín,Soengas, Raquel G.,Silva, Artur M. S.,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto
supporting information, p. 13104 - 13108 (2019/10/21)
In this work, the first example of a radical stereodivergent reaction directed towards the stereoselective synthesis of both (R*,R*)- and (R*,S*)-2,2′-biflavanones promoted by samarium diiodide is reported. Control experiments showed that the selectivity of this reaction was exclusively controlled by the temperature. It was possible to generate a variety of 2,2′-biflavanones bearing different substitution patterns at the aromatic ring in good-to-quantitative yields, being both stereoisomers of the desired compounds obtained with total or high control of selectivity. A mechanism that explains both the generation of the corresponding 2,2′-biflavanones and the selectivity is also discussed. The structure and stereochemistry determination of each isomer was unequivocally elucidated by single-crystal X-ray diffraction experiments.
