Substituted Phenyl Ring Research Articles

Copper-Catalysed Aminoboration of Vinylarenes with Hydroxylamine Esters-A Computational Mechanistic Study.

An in-depth computational probe of the copper-mediated formal aminoboration of β-alkylstyrenes with bis(pinacolato)diboron B2 pin2 and an archetype hydroxylamine ester by a dppbz-ligated {P^P}CuI boryl catalyst (dppbz≡{P^P}≡1,2-bis(diphenylphosphino)benzene) is presented. This first comprehensive computational study of the copper-mediated formal aminoboration utilising an electrophilic strategy has identified the most accessible pathway for productive catalysis. The mechanistic picture derived from smooth energy profiles acquired by employing a reliable computational protocol applied to a realistic catalyst model conforms to all available experimental data. The high degree of regio- and stereoselectivity achieved in syn-borylcupration and Umpolung electrophilic amination is instrumental to the exclusive generation of the (syn)-β-aminoalkylborane product. On the one hand, syn-borylcupration furnishes exclusively β-borylalkylcopper nucleophile upon boryl addition onto the vinylarene β-carbon. Its subsequent approach by the hydroxylamine electrophile to deliver the product with the release of {P^P}CuI benzoate favours a stepwise stereoretentive SN 2-type oxidative addition/N-C bond-forming reductive elimination sequence. The copper benzoate species represents the catalyst resting state, and its transformation into the catalytically active borylcopper species upon salt metathesis with Li(OtBu) base and transmetallation with B2 pin2 is turnover limiting. Electronically modified β-alkylstyrenes featuring a para-CF3 substituted phenyl ring render the borylcupration faster, and more electron-rich hydroxylamine agents decelerate the electrophilic amination.

Binding of Alkali Metal Ions with 1,3,5-Tri(phenyl)benzene and 1,3,5-Tri(naphthyl)benzene: The Effect of Phenyl and Naphthyl Ring Substitution on Cation−π Interactions Revealed by DFT Study

The effect of substitution of phenyl and naphthyl rings to benzene was examined to elucidate the cation-π interactions involving alkali metal ions with 1,3,5-tri(phenyl)benzene (TPB) and 1,3,5-tri(naphthyl)benzene (TNB). Benzene, TPB, and four TNB isomers (with ααα, ααβ, αββ, and βββ types of fusion) and their complexes with Li+, Na+, K+, Rb+, and Cs+ were optimized using DFT approach with B3LYP and M06-2X functionals in conjunction with the def2-QZVP basis set. Higher relative stability of β,β,β-TNB over α,α,α-TNB can be attributed to peri repulsion, which is defined as the nonbonding repulsive interaction between substituents in the 1- and the 8-positions on the naphthalene core. Binding energies, distances between ring centroid and the metal ions, and the distance to metal ions from the center of other six-membered rings were compared for all complexes. Our computational study reveals that the binding affinity of alkali metal cations increases significantly with the 1,3,5-trisubstitution of phenyl and naphthyl rings to benzene. The detailed computational analyses of geometries, partial charges, binding energies, and ligand organization energies reveal the possibility of favorable C-H···M+ interactions when a α-naphthyl group exists in complexes of TNB structures. Like benzene-alkali metal ion complexes, the binding affinity of metal ions follows the order: Li+ > Na+ > K+ > Rb+ > Cs+ for any considered 1,3,5-trisubstituted benzene systems. In case of TNB, we found that the strength of interactions increases as the fusion point changes from α to β position of naphthalene.

Radical scavenging potency of 2-(benzofuran-2-yl)-2-oxoethyl 3-(methyl/amino)benzoate: synthesis, crystal structure and Hirshfeld surface analysis

Abstract Two novel 2-(benzofuran-2-yl)-2-oxoethyl 3-(methyl/amino)benzoates 2(a–b), were synthesized under mild conditions and characterized by spectroscopic analysis. The three-dimensional (3D) crystal structures of these compounds were further determined using single crystal X-ray diffraction technique and revealed that both compounds tend to twist away with respect to their attached carbonyl groups at the C(=O)–C–O–C(=O) connecting bridge, exhibiting a nearly perpendicular conformation with torsion angle in a range of 75–94°. In both compounds, each of the benzofuran and substituted phenyl rings are individually planar while almost perpendicular to each other. Their molecular conformation are comparable with related structures from the Cambridge Structural Database (CSD). Furthermore, the intermolecular interactions in these crystal structures were quantified and analyzed using Hirshfeld surfaces computational method. The quantitative data on the percentage contributions of overall interactions on the molecules 2a and 2b (A & B) is calculated by the 2-D fingerprint plots from the HS analysis. These structures were evaluated for their antioxidant properties by diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferrous ion chelating (FIC) and hydrogen peroxide radical scavenging assays (H2O2). Noteworthy, compound 2b with an amino substituent attached to the phenyl ring exhibited an IC50 value of 45.37 μg/mL in H2O2 scavenging assay, which showed better scavenging effect than the standard drug, ascorbic acid (IC50=81.02 μg/mL).

Investigation of reactive and spectroscopic properties of oxobutanoic acid derivative: Combined spectroscopic, DFT, MD and docking study

The optimized geometry and wavenumbers of 4-[(4-acetylphenyl)amino]-2-methylidene-4-oxobutanoic acid (APAMOB) have been calculated by density functional theory (DFT) using Becke's three-parameters hybrid functional (B3LYP) with 6–311++G(d) (5D, 7F) basis set. The theoretically predicted vibrational wavenumbers were compared with the observed FT-IR and FT-Raman spectra. The NH stretching wavenumber is red shifted in the IR spectrum from the computed wavenumber, which indicates the weakening of the NH bond. The ring breathing mode of the para substituted phenyl ring is assigned at 836 cm−1 experimentally and at 835 cm−1 theoretically. Molecular electrostatic potential map has also been plotted for predicting the reactive sites in the molecule. Using natural bond orbitals analysis hyperconjugative interactions and second order stabilization energies are calculated. Nonlinear optical properties of the molecule are predicted. In order to determine molecule sites that could be sensitive towards electrophilic attacks we have calculated ALIE values and mapped them to electron density surface. In the same way we have also visualized Fukui functions, which helped us to further gain an insight into the local reactivity properties of title molecule. Bond dissociation energies (BDE) have been calculated in order to determine if autoxidation mechanism is possible, while the potential influence of hydrolysis was investigated to calculations of radial distribution functions (RDF) obtained after molecular dynamics (MD) simulations. Molecular docking study suggests that the title compound shows the inhibitory activity against 2-deoxy-d-gluconate 3-dehydrogenase.

Jack Bean Urease Inhibitors, and Antioxidant Activity Based on Palmitic acid Derived 1-acyl-3- Arylthioureas: Synthesis, Kinetic Mechanism and Molecular Docking Studies.

A series of acylthioureas was synthesized and their inhibitory effects on the DPPH and jack bean urease were evaluated. The results showed that all of the synthesized compounds exhibited significant jack bean urease inhibitory activities. Especially, 1-(4-chlorophenyl)-3 palmitoylthiourea 5a bearing 4-chloro substituted phenyl ring exhibited the most potent tyrosinase inhibitory activity with an IC50 value 0.0170 μM compared to the IC50 value of 4.720 μM of thiourea used as standard. The inhibition mechanism analyzed by Lineweaver-Burk plots revealed that the type of inhibition of compound 5a on tyrosinase was noncompetitive. The docking study against jack bean urease enzyme was also performed to determine the binding affinity of the compounds. The compounds 4c and 4e showed the highest binding affinity with the active binding site of tyrosinase. The initial structure activity relationships (SARs) analysis suggested that further development of such compounds might be of interest. The statistics of our results endorses that all compounds and particularly 5a may serve as a structural template for the design and development of novel urease inhibitors Graphical Abstract.

Study of the molecular structure on liquid crystal properties with reference to thermotropic azoester derivatives

ABSTRACTAn azoester homologues series: RO‒C6H4‒COO‒C10H6‒N˭N‒C6H4‒OC5H11 (para) as novel liquid crystalline (LC) materials has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on LC properties with reference to laterally substituted phenyl ring and terminally substituted ‒OR and ‒OC5H11 (n) groups; including ‒COO‒ and ‒N˭N‒ central bridges. Novel homologous series of thermotropic LC variety consists of thirteen homologues (C1 to C18). C1 to C3 derivatives are nonliquid crystal (NLC); C4 is only nematogenic and C5 to C18 are smectogenic plus nematogenic. All the mesogenic homologues (C4 to C18) are enantiotropically nematogenic or/and smectogenic as confirmed by a polarizing optical microscopy (POM) equipped with a heating stage. Transition curves Cr-I/M, Sm‒N, and N‒I behaved in normal manner in a phase diagram. Odd-even effect is exhibited by Sm‒N and N‒I transition curves. Analytical, spectral and thermal data confirms the molecular structure of novel homologues. Novel azoester series is predominantly nematogenic and partly smectogenic whose mesogenic temperatures ranges minimum to maximum from 79.0°C to 162.0°C. Thermal stability for smectic and nematic are 128.2°C and 147.7 °C, respectively. Thus, it is a middle ordered melting type of novel series whose total mesophaselength ranges from 20.0°C to 56.0°C. Textures of nematic are threaded or schlieren and that of smectic are smectic A or C.

Microsomal Metabolism of Prochiral Polychlorinated Biphenyls Results in the Enantioselective Formation of Chiral Metabolites.

Polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substituents and their metabolites exist as stable rotational isomers, or atropisomers, that are nonsuperimposable mirror images of each other. Additionally, the oxidation of certain axially prochiral PCBs, such as 2,2′,4,6′-tetrachlorobiphenyl (PCB 51) and 2,2′,4,5,6′-pentachlorobiphenyl (PCB 102), in the meta position of the symmetrically substituted phenyl ring is expected to form axially chiral hydroxylated metabolites (OH-PCBs); however, the formation of chiral OH-PCBs from prochiral PCBs has not been demonstrated experimentally. Here, we investigate if the oxidation of PCB 51 and PCB 102 by different microsomal preparations results in the formation of chiral OH-PCBs. Gas chromatographic analysis revealed that PCB 51 and PCB 102 were metabolized to 2,2′,4,6′-tetrachlorobiphenyl-3′-ol (OH-PCB 51) and 2,2′,4,5,6′-pentachlorobiphenyl-3′-ol (OH-PCB 102), respectively, by liver microsomes from male rats pretreated with different inducers; untreated male monkeys, guinea pigs, rabbits, and hamsters; and female dogs. The formation of both metabolites was inducer- and species-dependent. Both OH-PCB 51 and OH-PCB 102 were chiral and formed enantioselectively by all microsomal preparations investigated. These findings demonstrate that axially chiral PCB metabolites are formed from axially prochiral PCB congeners, a fact that should be considered when studying the environmental fate, transport, and toxicity of OH-PCBs.

Spectroscopic and reactive properties of a newly synthesized quinazoline derivative: Combined experimental, DFT, molecular dynamics and docking study

The molecular geometry, the normal mode wavenumbers and corresponding vibrational assignments, natural bond orbital analysis and the HOMO-LUMO analysis of 3-(4-oxo-phenethyl-3,4-dihydroquinazolin-2-ylthio)-N-(3,4,5-trimethoxyphenyl)propanamide were performed by B3LYP level of theory using the 6-311++G(d,p)(5D,7F) basis set. The experimentally obtained wavenumbers are in agreement with the theoretically predicted wavenumbrs. From the MEP plot it is evident that the negative charge covers carbonyl group, mono substituted phenyl ring, O59 atom and the positive region is over the nitrogen atoms and hydrogen atoms. NLO behavior of the title molecule was investigated by the determination of the first and second order hyperpolarizabilities. The molecular orbitals and molecular electrostatic potential map are also reported. The NMR spectra and Fukui indices are also analyzed. Molecule sites important from the aspect of reactivity have been determined by calculations of average local ionization energy (ALIE), Fukui functions and bond dissociation energies (BDE). BDE for hydrogen abstraction served us to investigate the possibility for autoxidation mechanism of the investigated molecule. Molecular dynamics (MD) simulations were used in order to investigate which atoms of the title molecule have the most pronounced interactions with water molecules. Molecular docking studies reveal that the inhibitor forms a stable complex with HNE as is evident from the binding affinity −10.9 kcal/mol and the results suggest that the compound exhibit inhibitory activity against HNE.

DFT and PCM-TD-DFT investigation of the electronic structures and spectra of 5-(3-phenyl-2-propenylidene)-2-thioxo-4-thiazolidinone derivatives

UV–Visible absorption spectra of 5-(3-phenyl-2-propenylidene)-2-thioxo-4-thiazolidinones (5pR-PPTT, R = H, CH3, CH3O, and N(CH3)2) were measured in different solvents and investigated using the theoretical PCM-TD-DFT scheme. A benchmark evaluation against experimental results on the accuracy of different DFT functionals has been performed. The best agreement with X-ray data is achieved by using the long-range corrected LC-wPBE functional, while the PBE0 functional provided the most accurate λmax for the studied compounds. The thionic forms of the ZE isomers of the studied compounds are found to be the most stable tautomers. The assignation debate of the second absorption band of rhodanine [2-thioxo-4-thiazolidinone (Rd)] has been solved by confirming on its π-π∗ nature. It was found that the expansion of the π-conjugation system at position 5 of Rd ring leads to significant bathochromic shift. The CT lengths (Δr) and dipole moment change (ΔμCT) indices showed that the charge transfer character of the electronic transitions is directly proportional to the electron-releasing strength of substituted phenyl ring. It was concluded that the red shifting of the maximum absorption is mainly regulated by the solvent polarizability and much less by solvent polarity.

New Dihydropyrimidines as Antimicrobial Agents

A series of novel dihydropyrimidines having benzo chromone and substituted phenyl ring along with pyrimidine nucleus have been synthesized under microwave irradiation. Synthesized compounds were characterized by physical, chemical and spectroscopic methods. Solvent free conditions, simple procedures, with high purity of the products in a very less time make this method highly valuable. The compounds were screened for antimicrobial properties to check their efficacy against few bacterial species. Results of the invitro antimicrobial activities showed that the compounds possess very promising antibacterial properties.

Synthesis and Antimicrobial Activity of Novel 3,7-Disubstituted 2H-1- Benzopyran-2-Ones

2H-1-benzopyran-2-one (Coumarin), an important oxygen heterocyclic scaffold, widely distributed throughout the plant kingdom, displayed a wide range of potential biological activities such as anti-microbial, anti-inflammatory and antioxidant activities. In this paper, we have synthesized a novel class of 3,7-disubstituted 2H-1-benzopyran- 2-one derivatives (3aa-3hb) bearing a basic ether side chain at C-7 and a substituted phenyl ring at C-3 of the coumarin ring. These compounds have been evaluated for anti-microbial (antibacterial/antifungal) activities. Some of the compounds 3ac, 3ae, 3bb, 3bc have shown significant anti-fungal activities against selective strains. Compound 3ae and 3bc with the MIC values of 1.56 μg/mL displayed better antifungal activity than fluconazole against Trichophyton mentagrophytes.

DESIGN AND SYNTHESIS OF 4-SUBSTITUTED QUINAZOLINE DERIVATIVES FOR THEIR ANTICONVULSANT AND CNS DEPRESSANT ACTIVITIES

<p><strong>Objective: </strong>The present work is designed to synthesise some isomeric new series of Quinazoline-4-one/4-thione derivatives, based on the pharmacophoric model of central nervous system (CNS) activity by structural modifications retaining the essential structural features for the activity and evaluated for their anticonvulsant and CNS depressant properties.</p><p><strong>Methods: </strong>A series of 7-chloro-3-[substituted (amino/phenylamino)]-2-phenyl quinazolin-4 (3H)-one/thione derivatives and 1-(7-chloro-4-oxo/-2-phenylquinazoline-3 (4H-yl)) substituted urea derivatives were prepared. The reaction scheme proceeds through the intermediate 7-chloro-2-phenyl-4H-benzo[d] [1, 3] oxazin-4-one. The structures of the newly synthesised compounds were characterized from infrared (IR), <sup>1</sup>H nuclear magnetic resonance (NMR) and mass spectra (m/z) and elemental analysis. The anti-convulsant and CNS depressant activity were investigated by maximum electroshock (MES) seizure test and porsolt’s behavioural despair test (forced swimming) respectively. The rota-rod test was performed to assess any probable changes in motor coordination induced by the test compounds.</p><p><strong>Results: </strong>The physicochemical and spectroscopic data clearly confirmed the synthesis of quinazoline derivatives with a common skeleton. The synthesised compounds were evaluated for their anticonvulsant and CNS depressant properties. Among them, six compounds <strong>(IIc, </strong>IIg, IIj, IIIc, IIIg, IIIj) exhibited a good activity profile in CNS depressant activity. Five compounds (IIc, IIg, IIj, IIIg, IIIh) showed protection against MES-induced seizures.</p><p><strong>Conclusion: </strong>The Quinazoline derivatives obtained from this research work indicates that the methyl/methoxy group in phenyl ring, amine and thiourea substitution at 3<sup>rd</sup> position of quinazoline derivatives are essential for CNS depressant activity as well as anticonvulsant activity. Compounds IIc, IIg, IIj, IIIc, IIIg, IIIj, and IIIh were found to be a potent compound which may be effective as a potential source for the development of CNS depressant and anti-convulsant drugs with lesser side effects</p>

Functional Characterization of a Novel Series of Biased Signaling Dopamine D3 Receptor Agonists.

Dopamine receptors play an integral role in controlling brain physiology. Importantly, subtype selective agonists and antagonists of dopamine receptors with biased signaling properties have been successful in treating psychiatric disorders with a low incidence of side effects. To this end, we recently designed and developed SK609, a dopamine D3 receptor (D3R) selective agonist that has atypical signaling properties. SK609 has shown efficacy in reversing akinesia and reducing L-dopa-induced dyskinesia in a hemiparkinsonian rats. In the current study, we demonstrate that SK609 has high selectivity for D3R with no binding affinity on D2R high- or low-affinity state when tested at a concentration of 10 μM. In addition, SK609 and its analogues do not induce desensitization of D3R as determined by repeated agonist treatment response in phosphorylation of ERK1/2 functional assay. Most significantly, SK609 and its analogues preferentially signal through the G-protein-dependent pathway and do not recruit β-arrestin-2, suggesting a functional bias toward the G-protein-dependent pathway. Structure-activity relationship (SAR) studies using analogues of SK609 demonstrate that the molecules bind at the orthosteric site by maintaining the conserved salt bridge interactions with aspartate 110 on transmembrane 3 and aryl interactions with histidine 349 on transmembrane 6, in addition to several hydrophobic interactions with residues from transmembranes 5 and 6. The compounds follow a strict SAR with reference to the three pharmacophore elements: substituted phenyl ring, length of the linker connecting phenyl ring and amine group, and orientation and hydrophobic branching groups at the amine among SK609 analogues for efficacy and functional selectivity. These features of SK609 and the analogues suggest that biased signaling is an inherent property of this series of molecules.

Design, synthesis, characterisation and in-vitro antimicrobial activity of some hybridized triazole scaffolds

In the present study, twelve hybridized triazole derivatives were synthesized as Glucosamine-6-phosphate synthase inhibitor and evaluated for in-vitro antimicrobial activity. The in-vitro antimicrobial results demonstrated that compound B4b, B4g and B4j possesses potential antibacterial activity against all the tested Gram positive and Gram negative bacterial strains with percentage zone of inhibition 70–89% and antifungal activity against all the screened fungal strains with 85–105%, displaying minimal inhibitory concentration values of 3.125–6.25 μg/mL against bacteria strains and 3.125–12.5 μg/mL against fungi strains compared with standard Gatifloxacin (for bacteria) and Clotrimazole (for fungi). Docking study reviews that the compounds which bind with Ser347, Thr352 and Val399 have significant anti-microbial activity. Comparing antimicrobial activity and docking results, conclude that triazolone derivatives linked through NC with substituted phenyl ring at 4th position seem to be potentially active. The docking study reveals that high affinity of synthesized derivatives (B4b, B4g and B4j) within the binding pocket of glucosamine-6-phosphate synthase strongly enhances the determined activities of these derivatives as potent antimicrobial agents, particularly as antifungal agents.

Vibrational spectroscopic investigations, molecular dynamic simulations and molecular docking studies of N′-diphenylmethylidene-5-methyl-1H-pyrazole-3-carbohydrazide

FT-IR and FT-Raman spectra of N′-diphenylmethylidene-5-methyl-1H-pyrazole-3-carbohydrazide were recorded and analyzed. Due to the industrial and biological importance of pyrazole derivatives, we have carried out an extensive quantum chemical study on N′-diphenylmethylidene-5-methyl-1H-pyrazole-3-carbohydrazide. The theoretical ground state geometry and electronic structure of the title molecule were optimized by DFT/B3LYP/6-311G++(d,p) method and compared with those of the crystal data. The wave numbers obtained are assigned by potential energy distribution. The ring breathing modes of the benzene rings are assigned theoretically at 1009 cm−1 for the mono substituted phenyl rings. The first order hyperpolarizability is comparable with that of similar derivatives and 16 times that of the standard NLO material urea. Conformational analysis was conducted in order to locate all possible conformations of the title compound, followed by investigation of local reactivity properties by MEP and ALIE surfaces. Natural bond orbital analysis has been carried out to analyse the stability of the molecule arising from hyper-conjugative interactions and charge delocalization. Further, reactive properties via autoxidation and hydrolysis mechanisms have been assessed through calculations of bond dissociation energies and radial distribution functions. Docking results confirmed that the compound was a potential inhibitor of CDK2s and were in agreement with the previous reported studies.

Design and Synthesis of Pyridone-Containing 3,4-Dihydroisoquinoline-1(2H)-ones as a Novel Class of Enhancer of Zeste Homolog 2 (EZH2) Inhibitors

A new enhancer of zeste homolog 2 (EZH2) inhibitor series comprising a substituted phenyl ring joined to a dimethylpyridone moiety via an amide linkage has been designed. A preferential amide torsion that improved the binding properties of the compounds was identified for this series via computational analysis. Cyclization of the amide linker resulted in a six-membered lactam analogue, compound 18. This transformation significantly improved the ligand efficiency/potency of the cyclized compound relative to its acyclic analogue. Additional optimization of the lactam-containing EZH2 inhibitors focused on lipophilic efficiency (LipE) improvement, which provided compound 31. Compound 31 displayed improved LipE and on-target potency in both biochemical and cellular readouts relative to compound 18. Inhibitor 31 also displayed robust in vivo antitumor growth activity and dose-dependent de-repression of EZH2 target genes.

Analysis of Intermolecular Interactions in 2,3,5 Trisubstituted Pyrazoles Derivatives: Insights into Crystal Structures, Gaussian B3LYP/6-311G (d,p), PIXELC and Hirshfeld Surface

Two derivatives of pyrazole have been synthesized with one of the systematic substitutions made on the ortho position of the phenyl ring attached to the pyrazole moiety and characterised via single crystal X-ray diffraction. The nature of the molecules appear as planar with the hydrogen bonding features analysed quantitatively. The derivatives are geometrically optimized and studied for its molecular confirmation at the B3LYP/6-311G (d,p). The structure overlay, molecular packing and intermolecular hydrogen bonding are studied quantitatively using Hirshfeld surface and 2D fingerprint plots. In both the compounds, packing of the molecules is derived via strong O–H···N and weak C–H···O, C–H···π interactions stabilizing the packing. Further, the structure overlay between the experimental structures and the geometrically optimized structures along with frequency analysis at the quantum chemical level shows the deviation in the central pyrazole moiety and the substituted phenyl ring with the RMSD value of 0.5051 and 0.6305 A respectively. The lattice energy is calculated for both the compounds using PIXELC module in Coulomb–London–Pauli (CLP) package and is partitioned into corresponding coulombic, polarization, dispersion and repulsion contributions.

Purine analogs as phosphatidylinositol 4-kinase IIIβ inhibitors

We report on an extensive structure–activity relationship study of novel PI4K IIIβ inhibitors. The purine derivative of the potent screening hit T-00127-HEV1 has served as a suitable starting point for a thorough investigation of positions 8 and 2. While position 8 of the purine scaffold can only bear a small substituent to maintain the inhibitory activity, position 2 is opened for extensive modification and can accommodate even substituted phenyl rings without the loss of PI4K IIIβ inhibitory activity. These empirical observations nicely correlate with the results of our docking study, which suggests that position 2 directs towards solution and can provide the necessary space for the interaction with remote residues of the enzyme, whereas the cavity around position 8 is strictly limited. The obtained compounds have also been subjected to antiviral screening against a panel of (+)ssRNA viruses.

Triazole tethered C5-curcuminoid-coumarin based molecular hybrids as novel antitubulin agents: Design, synthesis, biological investigation and docking studies

Keeping in view the confines allied with presently accessible antitumor agents and success of C5-curcuminoid based bifunctional hybrids as novel antitubulin agnets, molecular hybrids of C5-curcuminoid and coumarin tethered by triazole ring have been synthesized and investigated for in-vitro cytotoxicity against THP-1, COLO-205, HCT-116 and PC-3 human tumor cell lines. The results revealed that the compounds A-2 to A-9, B-2, B-3, B-7 showed significant cytotoxic potential against THP-1, COLO-205 and HCT-116 cell lines, while the PC-3 cell line among these was found to be almost resistant. Structure activity relationship revealed that the nature of Ring X and the length of carbon-bridge (n) connecting triazole ring with coumarin moiety considerably influence the activity. Methoxy substituted phenyl ring as Ring X and two carbon-bridges were found to be the ideal structural features. The most potent compounds (A-2, A-3 and A-7) were further tested for tubulin polymerization inhibition. Compound A-2 was found to significantly inhibit the tubulin polymerization (IC50 = 0.82 μM in THP-1 tumor cells). The significant cytotoxicity and tubulin polymerization inhibition by A-2 was further rationalized by docking studies where it was docked at the curcumin binding site of tubulin.

Structure and cytotoxic activity of terpenoid-like chalcones

Compounds with either ionone or chalcone skeletons present many biological properties including anticancer activity. Here we have prepared eight terpenoid-like chalcones in order to assess whether hybrid compounds with both structural frameworks could exhibit enhanced pharmacological profile. The terpenoid-like chalcones were synthesized by means of Claisen–Schmidt condensation reaction, using either α- or β-ionone with substituted benzaldehydes. The structure of six derivatives was elucidated by single crystal X-ray diffraction technique for the first time. Cyclohexene ring adopts half-chair conformation in α-ionone-derived chalcone with quaternary carbon at the flap, while twist puckering was observed in β-ionone terpenoid-like chalcones. All prepared compounds were tested for their cytotoxic activity against three cancer cell lines, namely SF-295, HCT-116 and OVCAR-8, which allowed us to establish some structure–activity relationships. Terpenoid-like chalcones with nitro substituted phenyl rings, regardless of its position and ionone type, were the most active chalcones among all that tested. The IC50 values do also reveal a trend of decrease in cytotoxic activity with weak electron-withdrawing groups at phenyl ring.