Active Compounds 4b Research Articles

Multicomponent reaction for synthesis, molecular docking, and anti-inflammatory evaluation of novel indole-thiazole hybrid derivatives.

In this article, novel thiazol-indolin-2-one derivatives 4a-f have been synthesized via treatment of thiosemicarbazide (1) with some isatin derivative 2a-f and N-(4-(2-bromoacetyl)phenyl)-4-tolyl-sulfonamide (3) under reflux in ethanol in the presence of triethyl amine (TEA). The structures of new products were elucidated by elemental and spectral analyses. Moreover, all compounds were investigated for their in vivo anti-inflammatory activity using celecoxib as a reference drug. The target compound 4b was the most active anti-inflammatory candidate and exhibited higher edema inhibition (EI = 38.50%) than that recorded by celecoxib (EI = 34.58%) after 3h. Furthermore, the most active compounds 4b and 4f were subjected to a molecular docking study inside COX-2 enzyme to show their binding interactions. Both compounds 4b and 4f showed good fitting into COX-2 binding site with docking energy scores -11.45kcal/mol and -10.48kcal/mol, respectively which indicated that compound 4b revealed the most promising and effective anti-inflammatory potential.

Design, synthesis, molecular docking, and dynamic studies of novel thiazole derivatives incorporating benzimidazole moiety and assessment as antibacterial agents.

A general and sustainable approach for the synthesis of benzimidazole-thiazole compounds via an efficient, one-pot, domino, pseudo-four-component reaction using 5-amino-2-mercaptobenzimidazole, aralkyl halides, ammonium thiocyanate, and substituted α-bromo-acetophenones in glacial acetic acid at ambient temperature to give final compounds (4a-p) in good yields in shorter time. The spectral data of synthesized compounds were evaluated by analytical and spectral techniques (IR, 1H-NMR, 13C-NMR, and ESI-HRMS). Further, some of the synthesized compounds were screened for their in-vitro antibacterial activity studies using the agar well diffusion method against Gram-positive Streptococcus pneumoniae (2451) bacteria and Gram-negative Proteous mirabilis (2081) bacteria. Based on the MIC results, it was observed that the most active compounds 4b, 4e, 4f, and 4k show promising antibacterial activity with the zone of inhibition values of 2.85cm 2.75cm, 3.6cm, and 3.3cm against both Gram-negative and positive bacteria cell lines, respectively. Further, we have also insight into the molecular simulation studies, based on the binding results, compound 4i showed stable binding interactions with streptomycin drug with the active site of the gyrase protein (PDB ID: 1KIJ). The structure-activity relationship (SAR) studies of all the title scaffolds were also established. The antibacterial activity, molecular docking studies, and molecular dynamic simulations of the title compounds suggested that these are promising antibacterial active skeletons.

Design, synthesis, in silico studies, and evaluation of novel chalcones and their pyrazoline derivatives for antibacterial and antitubercular activities

A new series of naphthyl chalcones (3a–3p) and their pyrazoline derivatives (4a–4h) were synthesized using substituted acetophenones, substituted naphthaldehydes, and hydrazine hydrate as starting materials. All the synthesized compounds were characterized by IR, NMR, and mass spectrometric analysis and screened for antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC 27924) and antibacterial activity against Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 441), Escherichia coli (MTCC 443) and Klebsiella pneumonia (MTCC 109). Compounds 3b and 3p exhibited significant antibacterial activity against all the tested bacterial strains. Amongst the synthesized compounds, compound 4b with 2-hydroxy-5-bromophenyl substitution at 3rd position of pyrazoline showed significant antimycobacterial activity with MIC of 6.25 µM comparable to that of standard isoniazid. The synthesized compounds were further screened for their cytotoxic activity against the MDA-MB-231 and SKOV3 cell lines. The compounds 3a, 3l, 4b, 4c, 4e, and 4h did not exhibit any cytotoxicity, and other compounds exhibited IC50 values higher than 8 and 22 µM against MDA-MB-231 and SKOV3 cell lines, respectively, compared to 1.20 and 1.30 µM shown by standard doxorubicin. To find out the putative binding mode of significantly active and weakly active compounds, a molecular docking study was also performed. In that, the most active compound 4b, displayed a hydrogen bond interaction with docking score of −10.50 kcal/mol and energy of −44.50 weakly active compound 3h did not show any crucial hydrogen bond interaction with the surrounded amino-acid residues and revealed a docking score of −6.74 and docking energy of −42.50.

Synthesis, characterization, structures and in vitro antitumor activity of platinum(II) complexes bearing adeninato or methylated adeninato ligands

Reactions of the carbonato platinum(II) complexes [Pt(CO3)(PPh3)2]·CH2Cl2 (1) and [Pt(CO3)(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane; 2) with adenine (3a) and its N6-methylated derivatives (N6-MeAde, 3b; N6,N6-Me2Ade, 3c) resulted under splitting off carbon dioxide in formation of bis(adeninato)platinum complexes [Pt(N6,N6-RR’Ade–H-κN9)2(PPh3)2] (4a–4c) and [Pt(N6,N6-RR’Ade–H-κN9)2(dppe)] (5a–5c) R/R’ = H, Me, respectively. Analogous reactions with adenines methylated at the N9 or N3 position (9-MeAde, 3d; N6,9-Me2Ade, 3e; 3-MeAde, 3f) gave cationic complexes which could be isolated as hexafluorophosphate salts: [Pt(9-MeAde–H-κ2N6,N7)(PPh3)2][PF6] (6a), [Pt(N6,9-Me2Ade–H-κ2N6,N7)(dppe)][PF6] (6b), and [Pt(3-MeAde–H-κ2N6,N7)(PPh3)2][PF6] (7). The deprotonation of the less acidic exocyclic N6HR (R = H, Me) group and the chelating κ2N6,N7 coordination in complexes 6/7 could unambiguously clarified by 1H,15N HMBC NMR spectroscopy and additionally by DFT calculations. All complexes were fully characterized especially by NMR (1H, 13C, 31P) and single-crystal X-ray structural investigations (4b∙2i-PrOH, 4c, 5a∙MeOH, and 5c∙1.5 MeOH). In vitro antitumoral activity was investigated against five tumor cell lines (A549 lung, A2780 ovarian, DLD-1 colon, FaDu head and neck, and SW1736 anaplastic thyroid). The most active compound 4b was found more active than cisplatin against cisplatin resistant DLD-1 (IC50 = 4.1 ± 0.5 µM) and SW1736 cell lines (IC50 = 1.5 ± 0.4 µM).

Indole-nitroimidazole conjugates as efficient manipulators to decrease the genes expression of methicillin-resistant Staphylococcus aureus

The biological resistance of methicillin-resistant staphylococcus aureus (MRSA) has pushed synthetic antibiotics to the forefront. To combat the resistance of MRSA, our new effort directed towards the development of novel structural candidates of enone-bridged indole nitroimidazole scaffolds, and wished to shed some light on the combination of some single pharmacophore with different biological activities. Bioassay revealed that the active compound 4b gave a satisfactory inhibition on MRSA (MIC = 1 μg/mL) and could effectively prevent the development of bacterial resistance. Mechanism exploration indicated that molecule 4b could not only intercalate into MRSA deoxyribonucleic acid (DNA), but also permeate MRSA membrane and bind with penicillin-binding protein 2a (PBP2a), then decreased the expression of three relevant genes in MRSA. Furthermore, it was able to be stored and carried by human serum albumin (HSA), and the participation of metal ions in 4b-HSA system was helpful to improve the supramolecular transport behavior. Hybrid 4b also exhibited low cytotoxicity towards normal lung epithelial cell line BEAS-2B.

Cp2ZrCl2: AN EFFICIENT CATALYST FOR MULTICOMPONENT SYNTHESIS OF CAROTENOID DEHYDROSQUALENE SYNTHASE INHIBITING PYRANO[2,3-d]PYRIMIDINEDIONES

Objectives: The present protocol deals with zirconocene dichloride (Cp2ZrCl2) catalyzed synthesis of pyrano[2,3-d]pyrimidinediones through one-pot multicomponent reactions of aromatic aldehydes with malononitrile and barbituric acid at ambient temperature. All the synthesized compounds were characterized and evaluated for antibacterial, antifungal, and antioxidant activities. Furthermore, a molecular docking was carried out to reveal the atomic insights between synthesized compounds and carotenoid dehydrosqualene synthase (PDB ID: 3ACX).
 Methods: All the synthesized compounds were evaluated for their in vitro antimicrobial activity by diffusion method. Antioxidant activities such as 1,1-diphenyl-2-picrylhydrazyl and radical scavenging activity. A mixture of barbituric acid 1 (1 mmol), malononitrile 2 (1 mmol), benzaldehyde 3a (1 mmol), ethanol (5 mL), and Cp2ZrCl2 (5 mol %) was stirred at ambient temperature for specified time. After completion of reaction as indicated by thin-layer chromatography, the obtained crude product was filtered and purified by column chromatography on silica gel (Merck, 60–120 mesh) using ethyl acetate:pet. ether to afford pure product which was then characterized by spectroscopic methods such by FTIR, nuclear magnetic resonance (1H NMR), 13C NMR, and mass spectroscopy.
 Results: All the synthesized pyrano[2,3-d]pyrimidinediones were characterized by spectroscopic analysis. The results revealed that pyrano[2,3-d] pyrimidinediones (4 a-k) displayed the zone of inhibition in the range of 3–13 mm. The most active compound 4b displayed largest zone of inhibition of 13 mm for Escherichia coli (NCIM-2832) and 9 mm for Bacillus subtilis (NCIM-2635). The antifungal and antioxidant activity of all synthesized pyrano[2,3-d]pyrimidinediones (4a-k) showed moderate to good activity. Molecular docking studies suggest that pyrano[2,3-d]pyrimidinediones might inhibit the carotenoid dehydrosqualene synthase activity.
 Conclusion: All the synthesized pyrano[2,3-d]pyrimidinediones display moderate to good antibacterial, antifungal, and antioxidant activity. This molecular docking studies supported that pyrano[2,3-d]pyrimidinediones might inhibit the carotenoid dehydrosqualene synthase (PDB ID: 3ACX).

Simple and efficient method for aromatization of tetrahydro-β-carbolines by using K2S2O8 as a catalyst and its antimicrobial activity comparison with molecular docking studies

A novel and efficient aromatization of tetrahydro-β-carbolines under mild conditions using K2S2O8 as a catalyst was developed. The method is applicable for all kinds of C1 substituted systems. All synthesized compounds were screened for their in vitro antibacterial activity against Staphylococus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumonia, as well as fungi, such as Aspergillus flavus and Fusarium oxysporum. Compounds 4b, 4g, 4i, and 4k demonstrated excellent in vitro antibacterial and antifungal activities than the standard drugs. The docking studies were carried out for most active compounds 4b, 4g, 4i, and 4k.

Design, synthesis, anticonvulsant evaluation and docking study of 2-[(6-substituted benzo[d]thiazol-2-ylcarbamoyl)methyl]-1-(4-substituted phenyl)isothioureas

In this paper, we report the synthesis of 2-[(6-substituted benzo[d]thiazol-2-ylcarbamoyl)methyl]-1-(4-substituted phenyl)isothiourea derivatives (4a-y) carrying active pharmacophores essential for anticonvulsant activity. The anticonvulsant activity was evaluated in vivo by maximal electroshock (MES) test and subcutaneous pentylenetetrazole (scPTZ) test in mice. Most of the compounds showed promising anticonvulsant activity. The most active compounds 4b and 4q were found active in both MES and scPTZ models, without signs of neurotoxicity. Compound 4b showed the moderate change in SGOT and alkaline phosphatase level as compared to control. Compounds 4b and 4w were also found to elevate GABA levels in the olfactory lobe, mid brain, medulla oblongata and cerebellum regions of rat brain. In molecular docking study, the title compounds exhibited good binding properties with epilepsy molecular targets such as GABA-A. Structure-activity relationships are also elaborated along with the analysis of lipophilicity. The results suggested that compound 4b is likely to have varied mechanisms of action including voltage-gated ion channel inhibition and modulating GABAergic action.

Synthesis and evaluation of 3-salicyloylpyridine derivatives as cytotoxic mitochondrial apoptosis inducers

A series of novel 3-salicyloylpyridines (4a–h) were synthesized with good yield by modified Knoevenagel–Stobbel method; o-allylation with allyl bromide lead to formation of compounds (5a–h). The synthesized compounds were characterized by spectroscopic techniques and evaluated for cytotoxic activity against human cancer cell lines. Compounds bearing hydroxyl group displayed high cytotoxicity (4a–h) as compared to o-allylated molecules (5a–h). The most active compound 4b was selected for further investigation to look for mechanism of cell death in prostate cancer (PC-3) cells. The apoptotic bodies induced by 4b in PC-3 cells were scanned by confocal microscopy and confirmed by scanning electron microscopy (SEM). Further results obtained from spectrofluorimetric determination of mitochondrial membrane potential (ΔΨm) and intracellular reactive oxygen species (ROS) in treated PC-3 cells revealed that mitochondria dependent apoptosis was involved in the cell death.

A new class of potential chloroquine-resistance reversal agents for Plasmodia: syntheses and biological evaluation of 1-(3'-diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines.

1-(3'-Diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines were synthesized and evaluated for CQ-resistant reversal activity. In general the compounds of the series elicit better biological response than their phenylmethyl analogues. The most active compound 4b has been evaluated in vivo in detail, and the results are presented. The possible mode of action of the compounds of this series is by inhibition of the enzyme heme oxygenase, thereby increasing the levels of heme and hemozoin, which are lethal to the parasite.

Synthesis of [formula omitted] and their antiallergic activity

The synthesis of a series of 4-amino/hydroxy-6-substituted- 1 2 -(2′,2′-diethoxyethyl)-1H/2H-pyrazolo[3,4-d]pyrimidines by alkylation of substituted pyrazolo[3,4- d]pyrimidines has been described, and their antiallergic activity evaluated in mice. The 2 most active compounds 4b and 5b were also tested in the rat. The most active compound 4b showed non-significant antihistaminic or antiserotoninergic activity.