Synthesis, molecular docking and biological evaluation of some newer 2-substituted-4-(benzo[d][1,3]dioxol-5-yl)-6-phenylpyridazin-3(2H)-ones as potential anti-inflammatory and analgesic agents

Mechanism, Chemoselectivity, and Stereoselectivity of an NHC-Catalyzed Reaction of Aldehydes and Hydrazones: A DFT Study

To elucidate the mechanism and origins of chemo- and enantioselectivities of the reaction between aliphatic aldehydes and hydrazones catalyzed by triazolium-derived NHC, density functional theory computations have been performed. According to our calculated results, the whole catalytic cycle for the formation of dihydropyridazinones proceeds via the initial nucleophilic addition of NHC to an aliphatic aldehyde, followed by the concerted intramolecular proton transfer and C-Cl bond cleavage. Subsequent deprotonation generates an enolate intermediate. The enolate intermediate then undergoes 1,4-addition to hydrazone to construct a new carbon-carbon bond. The following ring-closure would lead to a six-membered ring intermediate, which, upon the release of NHC, affords the final product dihydropyridazinone. The computation results reveal that intramolecular proton transfer is significantly promoted by the Brønsted acid DIPEA·H+. The carbon-carbon bond formation step could determine not only the chemoselectivity but also the stereoselectivity and lead to the S-isomer product. It was found that the stereoselectivity arises from a combination of weak interactions, including C-H···O, C-H···N, C-H···π, and LP···π. NHC could enhance the nucleophilicity of the aliphatic aldehyde and facilitate further reaction with hydrazone. This work could be beneficial for the development of new catalytic strategies in the future.

Pyridazine derivatives as selective COX-2 inhibitors: A review on recent updates

Selective cyclooxygenase (COX)-2 inhibitors have several advantages over nonselective COX inhibitors (nonsteroidal anti-inflammatory drugs [NSAIDs]), including the absence of adverse effects (renal and hepatic disorders) associated with the long-term use of standard NSAIDs, as well as an improved gastrointestinal profile. The pyridazine nucleus is regarded as a promising scaffold for the development of powerful COX-2 inhibitors, particularly when selectively functionalized. This article summarizes some methods for the synthesis of pyridazine derivatives. Furthermore, it covers all of the pyridazine derivatives that have appeared as selective COX-2 inhibitors, making it useful as a reference for the rational design of novel selective COX-2 inhibitors.

Carbene-catalyzed enantioselective annulation of dinucleophilic hydrazones and bromoenals for access to aryl-dihydropyridazinones and related drugs

4,5-Dihydropyridazinones bearing an aryl substituent at the C6-position are important motifs in drug molecules. Herein, we developed an efficient protocol to access aryl-dihydropyridazinone molecules via carbene-catalyzed asymmetric annulation between dinucleophilic arylidene hydrazones and bromoenals. Key steps in this reaction include polarity-inversion of aryl aldehyde-derived hydrazones followed by chemo-selective reaction with enal-derived α,β-unsaturated acyl azolium intermediates. The aryl-dihydropyridazinone products accessed by our protocol can be readily transformed into drugs and bioactive molecules.

Polarity inversion of arylidene hydrazones to react with bromoenals via carbene organic catalysis is disclosed. The reaction enantioselectively affords 6-aryl-4,5-dihydropyridazinones and related drugs with proven commercial applications.

Effect of Novel Pyrrolo[3,4-d]pyridazinone Derivatives on Lipopolysaccharide-Induced Neuroinflammation

Neuroinflammation is considered to be one of the potential causes for the development of neurodegenerative diseases, including Alzheimer's disease. In this study, we evaluated the effect of four newly synthesized pyrrolo[3,4-d]pyridazinone derivatives on the neuron-like PC12 cells under simulated inflammation conditions by preincubation with lipopolysaccharide (LPS). Our novel derivatives are selective cyclooxygenase-2 (COX-2) inhibitors and have similar effects to nonsteroidal anti-inflammatory drugs (NSAIDs). We assessed viability (LDH assay), metabolic activity (MTT assay), DNA damage (number of double-strand breaks measured by fast halo assay), and the neuronal features of cells (average neurite length and neurite outgrowth measured spectrofluorimetrically). DCF-DA and Griess assays were also performed, which allowed determining the impact of the tested compounds on the level of oxygen free radicals and nitrites. LPS administration significantly negatively affected the results in all tests performed, and treatment with the tested derivatives in most cases significantly reduced this negative impact. Multiple-criteria decision analysis indicated that overall, the best results were observed for compounds 2a and 2b at a concentration of 10 µM. The new derivatives showed intense activity against free oxygen radicals and nitrites. Reduced reactive oxygen species level also correlated with a decrease in the number of DNA damage. The compounds improved neuronal features, such as neurite length and outgrowth, and they also increased cell viability and mitochondrial activity. Our results suggest that derivatives 2a and 2b may also act additionally on mechanisms other than 3a and 3b.

Experimental and Computational Approaches for Solubility Measurement of Pyridazinone Derivative in Binary (DMSO + Water) Systems

The current research work was performed to evaluate the solubilization behavior, solution thermodynamics, and solvation behavior of poorly soluble pyridazinone derivative i.e., 6-phenyl-pyridazin-3(2H)-one (PPD) in various binary solvent systems of dimethyl sulfoxide (DMSO) and water using experimental and various computational approaches. The solubility of PPD in various binary solvent system of DMSO and water was investigated within the temperature range T = 298.2 K to 318.2 K at constant air pressure p = 0.1 MPa, by employing an isothermal technique. The generated solubility data of PPD was computationally represented by five different cosolvency models including van't Hoff, Apelblat, Yalkowsky-Roseman, Jouyban-Acree, and Jouyban-Acree-van't Hoff models. The performance of each computational model for correlation studies was illustrated using root mean square deviations (RMSD). The overall RMSD value was obtained <2.0% for each computational model. The maximum solubility of PPD in mole fraction was recorded in neat DMSO (4.67 × 10-1 at T = 318.2 K), whereas the lowest one was obtained in neat water (5.82 × 10-6 at T = 298.2 K). The experimental solubility of PPD in mole fraction in neat DMSO was much higher than its ideal solubility, indicating the potential of DMSO for solubility enhancement of PPD. The computed values of activity coefficients showed maximum molecular interaction in PPD-DMSO compared with PPD-water. Thermodynamic evaluation showed an endothermic and entropy-driven dissolution of PPD in all the mixtures of DMSO and water. Additionally, enthalpy-entropy compensation evaluation indicated an enthalpy-driven mechanism as a driven mechanism for the solvation property of PPD.

Synthesis, Characterization and Solubility Determination of 6-Phenyl-pyridazin-3(2H)-one in Different Pharmaceutical Solvents

The current research work proposed the solubility data and solution thermodynamic properties of the cardiovascular agent 6-phenylpyridazin-3(2H)-one [PPD] in twelve pharmaceutical solvents at "T = 298.2 K to 318.2 K" and "p = 0.1 MPa". The measured solubilities of PPD were regressed well with "van't Hoff and Apelblat models". The solid phases of pure and equilibrated PPD were characterized using differential scanning calorimetry and powder X-ray differactometry, and the results suggested no transformation of PPD into solvates/hydrates/polymorphs after equilibrium. The solubilities of PPD in a mole fraction at "T = 318.2 K" were noted at a maximum in dimethyl sulfoxide (DMSO, 4.73 × 10^-1), followed by polyethylene glycol-400 (PEG-400, 4.12 × 10^-1), Transcutol^® (3.46 × 10^-1), ethyl acetate (EA, 81 × 10^-2), 2-butanol (2.18 × 10^-2), 1-butanol (2.11 × 10^-2), propylene glycol (PG, 1.50 × 10^-2), isopropyl alcohol (IPA, 1.44 × 10^-2), ethylene glycol (EG, 1.27 × 10^-2), ethanol (8.22 × 10^-3), methanol (5.18 × 10^-3) and water (1.26 × 10^-5). Similar tendencies were also noted at other studied temperatures. The results of the "apparent thermodynamic analysis" showed an endothermic and entropy-driven dissolution of PPD in all pharmaceutical solvents. The results of the activity coefficients suggested a maximum interaction at the molecular level in PPD-DMSO, PPD-PEG-400 and PPD-Transcutol, compared with other combination of the solute and solvents.

Synthesis and biological evaluation of a new series of ortho-carboranyl biphenyloxime derivatives

(Z,Z’)-1,1′-(4-ortho-Caboranyldimethyl)-bis(2-methoxyphenylethan-1-oxime) intermediate 3 was synthesized by a three-step reaction with a final treatment with base to give a new series of ortho-carboranyl biphenyloxime derivatives (4–8). Compounds 7 and 8 showed high solubility and the in vitro study results revealed high levels of accumulation in HeLa cells with higher cytotoxicity and boron uptake compared to l-boronphenylalanine.

Synthesis, anti-microbial activity, cytotoxicity of some novel substituted (5-(3-(1H-benzo[d]imidazol-2-yl)-4-hydroxybenzyl)benzofuran-2-yl)(phenyl)methanone analogs

Background

There is a dire need for the discovery and development of new antimicrobial agents after several experiments for a better resistance of microorganisms towards antimicrobial agents become a serious health problem for a few years in the past. As benzimidazole possess various types of biological activities, it has been synthesized, in the present study, a new series of (5-(3-(1H-benzo[d]imidazol-2-yl)-4-hydroxybenzyl)benzofuran-2-yl)(phenyl)methanone analogs by using the condensation and screened for its in vitro antimicrobial activity and cytotoxicity.

Results

The synthesized (5-(3-(1H-benzo[d]imidazol-2-yl)-4-hydroxybenzyl) benzofuran-2-yl)(phenyl)methanone analogs were confirmed by IR, ¹H and ¹³C-NMR, MS spectra and HRMS spectral data. The synthesized compounds were evaluated for their in vitro antimicrobial potential against Gram-positive (Bacillus subtilis, Bacillus megaterium, Staph aureus and Streptococcus pyogenes), Gram-negative (Escherichia coli, Proteus vulgaris, Proteus mirabilis and Enterobacter aerogenes) bacterial and fungal (Aspergillus niger, Candida albicans, Fusarium oxysporum, Fusarium solani) strains by disc diffusion method and the minimum inhibitory concentration (MIC) in which it has been recorded in microgram per milliliter in comparison to the reference drugs, ciprofloxacin (antibacterial) and nystatin (antifungal). Further, the cytotoxicity (IC₅₀ value) has also been assessed on human cervical (HeLa), Supt1 cancer cell lines by using MTT assay.

Conclusions

The following screened compounds (4d), (4f), (4g), (4k), (4l), (4o) and (4u) were found to be the best active against all the tested bacterial and fungal strains among all the demonstrated compounds of biological study. The MIC determination was also carried out against bacteria and fungi, the compounds (4f) and (4u) are found to be exhibited excellent potent against bacteria and fungi respectively. The compounds (4f) and (4u) were shown non-toxic in nature after screened for cytotoxicity against the cancer cell lines of human cervical (HeLa) and Supt1. Additionally, structure and antibacterial activity relationship were also further supported by in silico molecular docking studies of the active compounds against DNA topoisomerase.

Electronic supplementary material

The online version of this article (10.1186/s13065-017-0364-3) contains supplementary material, which is available to authorized users.