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Computational studies based on Density Functional Theory (DFT) and time-dependent DFT (TD-DFT) were used to determine molecular and thermodynamic parameters, optoelectronic and electronic properties, as well as chemical descriptors, UV–vis spectra and nonlinear optical response of the chromophores of 2-Styrylquinoline (M01) and 2-(3-nitrostyryl)quinoline (M02). We evaluated the impact of the substitution of the hydrogen atom in M01 by the nitro group (NO2) to obtain the molecule M02. The results show very good optoelectronic properties with respect to very high electric fields of the order of 1.43 × 109 Vm−1 for M01 up to 5.26 × 109 Vm−1 for M02. The energy gap decreases from 3.94 eV for M01 to 3.56 eV for M02; which suggest that they are semiconductors. In addition, these two molecules exhibit ionization potential (IP) and electron affinity (EA) quite close to those of Alq3 and could therefore be good candidates for the manufacture of Organic Light-Emitting Diodes (OLED). The chemical descriptors were assessed and allowed us to discuss the stability and reactivity of our molecules. Thus, the addition of the nitro group to the virgin 2-Styrylquinoline decreases the reactivity and stability of the 2-Styrylquinoline. The analysis of the IR and Raman vibrational spectra shows several peaks between 100 cm−1 and 3200 cm−1 of which the most intense for the molecule M01 are attributed to the stretching mode of the C–H bond in the phenyl ring and the C=C double bond in the quinoline ring. For the M02 molecule, stronger peaks were assigned to the stretching mode of the O–N and N–C bonds. The analysis of the UV–vis spectra showed that the maximum absorption wavelength of M01 is 334.80 nm and that of M02 is 375.37 nm; both located in the ultraviolet. The high values of first ( β T ) and second ( γ ¯ ) hyperpolarizability showed that both molecules have very good nonlinear optical properties and thus can be used for second and third harmonic generation. [ABSTRACT FROM AUTHOR]

Three new styrylquinoline–chalcone hybrids have been synthesized using a three‐step pathway starting with Friedländer cyclocondensation between (2‐aminophenyl)chalcones and acetone to give 2‐methyl‐4‐styrylquinolines, followed by selective oxidation to the 2‐formyl analogues, and finally Claisen–Schmidt condensation between the formyl intermediates and 1‐acetylnaphthalene. All intermediates and the final products have been fully characterized by IR and 1H/13C NMR spectroscopy, and by high‐resolution mass spectrometry, and the three products have been characterized by single‐crystal X‐ray diffraction. The molecular conformations of (E)‐3‐{4‐[(E)‐2‐phenylethenyl]quinolin‐2‐yl}‐1‐(naphthalen‐1‐yl)prop‐2‐en‐1‐one, C30H21NO, (IVa), and (E)‐3‐{4‐[(E)‐2‐(4‐fluorophenyl)ethenyl]quinolin‐2‐yl}‐1‐(naphthalen‐1‐yl)prop‐2‐en‐1‐one, C30H20FNO, (IVb), are very similar. In each compound, the molecules are linked into a three‐dimensional array by hydrogen bonds, of the C—H...O and C—H...N types in (IVa), and of the C—H...O and C—H...π types in (IVb), and by two independent π–π stacking interactions. By contrast, the conformation of the chalcone unit in (E)‐3‐{4‐[(E)‐2‐(2‐chlorophenyl)ethenyl]quinolin‐2‐yl}‐1‐(naphthalen‐1‐yl)prop‐2‐en‐1‐one, C30H20ClNO, (IVc), differs from those in (IVa) and (IVb). There are only weak hydrogen bonds in the structure of (IVc), but a single rather weak π–π stacking interaction links the molecules into chains. Comparisons are made with some related structures. [ABSTRACT FROM AUTHOR]

Three new 4‐styrylquinoline–benzimidazole hybrids have been synthesized using a reaction sequence in which 2‐methylquinoline precursors first undergo selective oxidation by selenium dioxide to form the corresponding 2‐formylquinoline intermediates, followed by oxidative cyclocondensation reactions with benzene‐1,2‐diamine to yield the hybrid products. The formyl intermediates and the hybrid products have all been fully characterized using a combination of IR, 1H and 13C NMR spectroscopy, and high‐resolution mass spectrometry, and the structures of the three hybrid products have been determined using single‐crystal X‐ray diffraction. Ethyl (E)‐2‐(1H‐benzo[d]imidazol‐2‐yl)‐4‐(4‐chlorostyryl)quinoline‐3‐carboxylate, C27H20ClN3O2, (IIIa), and ethyl (E)‐2‐(1H‐benzo[d]imidazol‐2‐yl)‐4‐(2‐methoxystyryl)quinoline‐3‐carboxylate, C28H23N3O3, (IIIb), both crystallize in the solvent‐free form with Z′ = 1, but ethyl (E)‐2‐(1H‐benzo[d]imidazol‐2‐yl)‐4‐(4‐methylstyryl)quinoline‐3‐carboxylate, C28H23N3O2, (IIIc), crystallizes as a partial hexane solvate with Z′ = 3, and the ester group in one of the independent molecules is disordered over two sets of atomic sites having occupancies of 0.765 (7) and 0.235 (7). The molecules of (IIIc) enclose continuous channels which are occupied by disordered solvent molecules having partial occupancy. In all of the molecules of (IIIa)–(IIIc), the styrylquinoline fragment is markedly nonplanar. Different combinations of N—H...O and C—H...π hydrogen bonds generate supramolecular assemblies which are two‐dimensional in (IIIb) and (IIIc), but three‐dimensional in (IIIa). Comparisons are made with the structures of some related compounds. [ABSTRACT FROM AUTHOR]

The aim of the study was to present the influence of various styrylquinoline (StQ) substituents on the luminescence, structural, and optical properties of StQ-containing copolymers. StQ-containing copolymers were synthesized by free-radical thermoinitiated polymerization. The calculations of the copolymerization ratios for the obtained copolymers were based on the basis of the integrated peak areas of the 1H NMR spectra in CDCl3. The luminescence measurements show that the change in the nature of the electron-donating and electron-withdrawing of the substituent shifts the emission band to longer wavelengths and causes a transition from blue fluorescence to green or yellow and orange (or even white), regardless of the electronic nature of the introduced substituent group. The structural properties were measured by Fourier-Transform Infrared (FTIR) and Raman spectroscopies. For all of the compounds, we observed similarities in the bands in FTIR and Raman measurements. The optical parameters were obtained from the absorbance measurements. Additionally, Scanning Electron Microscopy (SEM) was used to study the surface topography of the thin layers on the glass substrate. The SEM images confirm that we obtained smoother layers for two copolymers. The computational Density Functional Theory (DFT) analysis fully supports the beneficial features of the analyzed systems for their applications in optoelectronic devices. Based on the obtained results, it can be concluded that all of the studied styrylquinolines are promising materials for applications in organic light-emitting diodes (OLEDs). However, COP1 with an OCH3 donor substituent possess a wider luminescence band, and its layer is smoother and more transparent. [ABSTRACT FROM AUTHOR]

Hartree-Fock (HF) and Density Functional Theory (DFT) studies were conducted to assess the impact of potassium doping on the thermodynamic, optoelectronic, electronic and nonlinear optical properties and on the reactivity of photochromic polymers containing styrylquinoline fragments. Doping was carried out on the virgin monomer (M1) and on the derivative monomer (M2) with the nitro group NO2. Three doped monomers were investigated including, the monomer M3 obtained from M1 by substituting the H atom with a potassium, the monomer M4 by substituting two H atoms and the monomer M5 obtained from M2 by substituting the H atom. Findings proved that the use of potassium and the nitro group is an excellent process to improve the electronics properties of styrylquinoline virgin monomers. In fact, the energy gap decreases from 3.82 eV for M1 to 3.02 eV and to 2.92 eV for M3 and M4, respectively; while the decrease from 3.43 eV for M2 to 2.52 eV for M5 was observed, thus demonstrating the good semiconductor character of the obtained compounds with relevant applications in the manufacture of solar cells. Likewise, the fundamental gap decreases from 6.50 eV for M1 to 5.34 eV and to 4.62 eV for M3 and M4, respectively; while the decrease from 6.11 eV for M2 to 5.21 eV for M5 was observed; thus demonstrating an improvement in the reactivity of our doped monomers. In addition, potassium doping is an appropriate method to enhance optoelectronic properties of styrylquinoline virgin monomers. Thus, the refractive index of our doped monomers is greater than that of glass, which is a reference in optic and can be used under high electric fields of the order of 1.90×109 Vm−1 for monomer M4 up to 7.01×109 Vm−1 for M3 and to 10.89×109 Vm−1 for M5. Finally, the strong enhancement of the linear and nonlinear optical (NLO) properties that we observed leads us to conclude that these doped monomers can be appropriate candidates in devices requiring good NLO properties.

The aim of the study was to present the influence of various styrylquinoline (StQ) substituents on the luminescence, structural, and optical properties of StQ-containing copolymers. StQ-containing copolymers were synthesized by free-radical thermoinitiated polymerization. The calculations of the copolymerization ratios for the obtained copolymers were based on the basis of the integrated peak areas of the 1H NMR spectra in CDCl3. The luminescence measurements show that the change in the nature of the electron-donating and electron-withdrawing of the substituent shifts the emission band to longer wavelengths and causes a transition from blue fluorescence to green or yellow and orange (or even white), regardless of the electronic nature of the introduced substituent group. The structural properties were measured by Fourier-Transform Infrared (FTIR) and Raman spectroscopies. For all of the compounds, we observed similarities in the bands in FTIR and Raman measurements. The optical parameters were obtained from the absorbance measurements. Additionally, Scanning Electron Microscopy (SEM) was used to study the surface topography of the thin layers on the glass substrate. The SEM images confirm that we obtained smoother layers for two copolymers. The computational Density Functional Theory (DFT) analysis fully supports the beneficial features of the analyzed systems for their applications in optoelectronic devices. Based on the obtained results, it can be concluded that all of the studied styrylquinolines are promising materials for applications in organic light-emitting diodes (OLEDs). However, COP1 with an OCH3 donor substituent possess a wider luminescence band, and its layer is smoother and more transparent.

A new series of 4,6-disubstituted 2-(4-(dimethylamino)styryl)quinoline 4a,b–9a,b was synthesized by the reaction of 2-(4-(dimethylamino)styryl)-6-substituted quinoline-4-carboxylic acids 3a,b with thiosemicarbazide, p-hydroxybenzaldehyde, ethylcyanoacetate, and 2,4-pentandione. In addition, the antitumour activity of all synthesized compounds 3a,b–9a,b was studied via MTT assay against two cancer cell lines (HepG2 and HCT116). Furthermore, epidermal growth factor receptor (EGFR) inhibition, using the most potent antitumour compounds, 3a, 3b, 4a, 4b, and 8a, was evaluated. The interpretation of the results showed clearly that the derivatives 3a, 4a, and 4b exhibited the highest antitumour activities against the tested cell lines HepG2 and HCT116 with IC50 range of 7.7–14.2 µg/ml, in comparison with the reference drugs 5-fluorouracil (IC50 = 7.9 and 5.3 µg/ml, respectively) and afatinib (IC50 = 5.4 and 11.4 µg/ml, respectively). In vitro EGFR screening showed that compounds 3a, 3b, 4a, 4b, and 8a exhibited moderate inhibition towards EGFR with IC50 values at micromolar levels (IC50 range of 16.01–1.11 µM) compared with the reference drugs sorafenib (IC50 = 1.14 µM) and erlotinib (IC50 = 0.1 µM). Molecular docking was performed to study the mode of interaction of compounds 3a and 4b with EGFR kinase.

Drugs against malaria are losing their effectiveness because of emerging drug resistance. This underscores the need for novel therapeutic options for malaria with mechanism of actions distinct from current antimalarials. To identify novel pharmacophores against malaria we have screened compounds containing structural features of natural products that are pharmacologically relevant. This screening has identified a 4-nitro styrylquinoline (SQ) compound with submicromolar antiplasmodial activity and excellent selectivity. SQ exhibits a cellular action distinct from current antimalarials, acting early on malaria parasite's intraerythrocytic life cycle including merozoite invasion. The compound is a fast-acting parasitocidal agent and also exhibits curative property in the rodent malaria model when administered orally. In this report, we describe the synthesis, preliminary structure-function analysis, and the parasite developmental stage specific action of the SQ scaffold.

Abstract Functionalized photochromic materials have attracted a growing interest during the last few decades since they are promising materials to be used in optoelectronics and photonics. In this paper, the results of the nonlinear optical (NLO) investigation (second and third harmonic generation) of spin deposited high-quality thin films of styrylquinoline containing methacrylic polymers studied by using Maker fringes technique employing 30 ps laser pulses at fundamental wavelength of 1064 nm are presented. Photochromic styrylquinoline units were oriented in the thin films by corona poling technique promoting second order NLO activity. Strong dependence of the NLO response upon the structure of the polymers has been found, which is related to the different charge transfer within the styrylquinoline fragments. These investigations were completed by theoretical studies using HOMO-LUMO energy levels theory and the first and second order hyperpolarizability values. Good compatibility has been achieved between the theoretical and experimental results. Studied styrylquinoline-based polymers showed the contrast in NLO response after their trans-cis photoisomerization making them interesting for using in photonic devices. Graphical abstract Image 1057 Highlights • Control of NLO response upon the molecular structure of the styrylquinoline fragments. • Strong charge transfer lead to strong NLO modulation of NLO properties. • High electron delocalization induce large NLO properties. • Trans -cis photoisomerization lead to photoswitchable NLO properties due to UV irradiation. [ABSTRACT FROM AUTHOR]

A nickel catalyzed straightforward method for the construction of functionalized 4‐styrylquinolines via Friedlander coupling of 2′‐aminochalcones with 1,3‐dicarbonyl compounds or cyclic ketones is described. This method offers both cycloalkyl and styryrl groups fused quinoline skeleton in one pot. Further, 4‐styrylquinolines on treatment with aryl aldehydes gave corresponding 2,4‐distyrylquinolines in highly regioselective manner. A nickel catalyzed annulation of 2'‐aminochalcones with mono and di‐keto compounds to access 4‐styrylquinolines by Friedlander strategy and its application to give 2,4‐distyrylquinolines is described in high yields. [ABSTRACT FROM AUTHOR]

A new series of 4,6-disubstituted 2-(4-(dimethylamino)styryl)quinoline 4a,b-9a,b was synthesized by the reaction of 2-(4-(dimethylamino)styryl)-6-substituted quinoline-4-carboxylic acids 3a,b with thiosemicarbazide, p-hydroxybenzaldehyde, ethylcyanoacetate, and 2,4-pentandione. In addition, the antitumour activity of all synthesized compounds 3a,b-9a,b was studied via MTT assay against two cancer cell lines (HepG2 and HCT116). Furthermore, epidermal growth factor receptor (EGFR) inhibition, using the most potent antitumour compounds, 3a, 3b, 4a, 4b, and 8a, was evaluated. The interpretation of the results showed clearly that the derivatives 3a, 4a, and 4b exhibited the highest antitumour activities against the tested cell lines HepG2 and HCT116 with IC50 range of 7.7-14.2 µg/ml, in comparison with the reference drugs 5-fluorouracil (IC50 = 7.9 and 5.3 µg/ml, respectively) and afatinib (IC50 = 5.4 and 11.4 µg/ml, respectively). In vitro EGFR screening showed that compounds 3a, 3b, 4a, 4b, and 8a exhibited moderate inhibition towards EGFR with IC50 values at micromolar levels (IC50 range of 16.01-1.11 µM) compared with the reference drugs sorafenib (IC50 = 1.14 µM) and erlotinib (IC50 = 0.1 µM). Molecular docking was performed to study the mode of interaction of compounds 3a and 4b with EGFR kinase. [ABSTRACT FROM AUTHOR]

Spectral and photochemical properties of 1-(9-phehanthryl)-2-(2-quinolyl)ethylene (9Ph2QE) in neutral and protonated forms have been investigated. It has been found that both isomers of 9Ph2QE are photoactive. The quantum yield of trans-cis photoisomerization (ϕtc = 0.47) in the neutral form is typical of the diabatic photoisomerization; on passing to the protonated form, ϕtc increases up to 0.70. Thus, the double annelation of the 2-styrylquinoline phenyl group to form 9Ph2QE makes it possible to conserve the α-effect, which consists in an increase in the quantum yield to ϕtc > 0.5 on passing from the neutral to protonated form, whereas the effect disappears for other types of annelation (naphthylquinolylethylenes, 1-(9-anthryl)-2-(2-quinolyl)ethylene). [ABSTRACT FROM AUTHOR]

7-Nicotinoyl-styrylquinoline (MB96) displays an antiviral activity on HIV-1 infected CEM cell lines and is a promising inhibitor of the serine/threonine-protein Pim-1 kinase. By means of UV–vis spectroscopy supported by theoretical calculations this styrylquinoline is shown to exist in different conformations: the s-trans planar conformation along with other twisted ones with respect to the torsion around the single bond between the quinoline and the phenylethenyl appendage. Hydrogen bonding interactions with the solvent shift the skeleton of the MB96 towards the planar form, enhancing conjugation of π-electrons between the quinoline and the catechol parts, while self-association process seems furthering this planar conformation. [ABSTRACT FROM AUTHOR]

Drugs against malaria are losing their effectiveness because of emerging drug resistance. This underscores the need for novel therapeutic options for malaria with mechanism of actions distinct from current antimalarials. To identify novel pharmacophores against malaria we have screened compounds containing structural features of natural products that are pharmacologically relevant. This screening has identified a 4-nitro styrylquinoline (SQ) compound with submicromolar antiplasmodial activity and excellent selectivity. SQ exhibits a cellular action distinct from current antimalarials, acting early on malaria parasite's intraerythrocytic life cycle including merozoite invasion. The compound is a fast-acting parasitocidal agent and also exhibits curative property in the rodent malaria model when administered orally. In this report, we describe the synthesis, preliminary structure-function analysis, and the parasite developmental stage specific action of the SQ scaffold. [ABSTRACT FROM AUTHOR]

Algunas de las drogas más usadas y efectivas en los tratamientos antileucémicos poseen como estructura química principal anillos de quinolina y grupos estireno, lo que podría sugerir que compuestos análogos a estos servirían como posibles nuevos agentes antiproliferativos. Recientemente, uno de nuestros laboratorios sintetizó 6 nuevos análogos de estirilquinolina, candidatas para efectos antiproliferativos y/o anticancerígenos. Así, mediante el ensayo colorimétrico (MTT) se evaluó la citotoxicidad de los seis compuestos en la línea celular Jurkat de origen leucemoide. Los resultados muestran ausencia de efecto citotóxico en las concentraciones y tiempos evaluados. Además, cuando los tratamientos fueron aplicados en presencia de la fracción microsomal S9, no se alteró la viabilidad en este modelo celular leucemoide in vitro. Queda abierta la posibilidad de evaluar estas estirilquinolinas en otras líneas celulares y/o que representen otro modelo de enfermedades, con miras a tamizar efectos biomédicos promisorios.Some of the most commonly used and effective drugs used in antileukemic treatments posses principal chemical structures with quinoline rings and/or styrene groups, which might suggest that analogous compounds may serve as potential new antiproliferative agents. Recently, one of our laboratories synthesised six new styrylquinoline analogues as candidates for having antiproliferative and/or anti-cancer effects. Thus, using the MTT assay we evaluated the cytotoxicity of these six compounds in the leukemoid cell line Jurkat. The results showed an absence of cytotoxic effects at the concentrations and times assayed. In addition, when the treatments were applied in the presence of S9 microsomal fraction, cell viability was not altered in this leukemoid in vitro model. These results open the possibility of evaluating these styrylquinolines in other cell lines or diseases models with the goal of examining promising biomedical effects.

In spite of significant progress in anti-HIV-1 therapy, current antiviral chemo-therapy still suffers from deleterious side effects and emerging drug resistance. Therefore, the development of novel antiviral drugs remains a crucial issue for the fight against AIDS. HIV-1 integrase is a key enzyme in the replication cycle of the retrovirus since it catalyzes the integration of the reverse transcribed viral DNA into the chromosomal DNA. Efforts to develop anti-integrase drugs started during the early nineties, culminating with the recent approval of Raltegravir. The discovery and the development of the styrylquinoline inhibitor class was an important step in the overall process. In this review we have described the key synthetic issues and the structure-activity relationship of this family of integrase inhibitors. Crystallographic and docking studies that shed light on their mechanism of action are also examined.

Highlights: [•] Forster resonance energy transfer (FRET) occurs in bichromophoric dyad. [•] FRET quenches trans → cis photoisomerization of styrylquinoline (SQ) moiety. [•] SQ trans → cis photoisomerization is switched on in protonated dyad. [•] Effect of “one-way” photoisomerization in the dyad is kinetic in nature. [ABSTRACT FROM AUTHOR]

Hartree-Fock (HF) and Density Functional Theory (DFT) studies were conducted to assess the impact of potassium doping on the thermodynamic, optoelectronic, electronic and nonlinear optical properties and on the reactivity of photochromic polymers containing styrylquinoline fragments. Doping was carried out on the virgin monomer (M1) and on the derivative monomer (M2) with the nitro group NO 2 . Three doped monomers were investigated including, the monomer M3 obtained from M1 by substituting the H atom with a potassium, the monomer M4 by substituting two H atoms and the monomer M5 obtained from M2 by substituting the H atom. Findings proved that the use of potassium and the nitro group is an excellent process to improve the electronics properties of styrylquinoline virgin monomers. In fact, the energy gap decreases from 3.82 eV for M1 to 3.02 eV and to 2.92 eV for M3 and M4, respectively; while the decrease from 3.43 eV for M2 to 2.52 eV for M5 was observed, thus demonstrating the good semiconductor character of the obtained compounds with relevant applications in the manufacture of solar cells. Likewise, the fundamental gap decreases from 6.50 eV for M1 to 5.34 eV and to 4.62 eV for M3 and M4, respectively; while the decrease from 6.11 eV for M2 to 5.21 eV for M5 was observed; thus demonstrating an improvement in the reactivity of our doped monomers. In addition, potassium doping is an appropriate method to enhance optoelectronic properties of styrylquinoline virgin monomers. Thus, the refractive index of our doped monomers is greater than that of glass, which is a reference in optic and can be used under high electric fields of the order of 1.90 × 10 9 Vm -1 for monomer M4 up to 7.01 × 10 9 Vm -1 for M3 and to 10.89 × 10 9 Vm -1 for M5. Finally, the strong enhancement of the linear and nonlinear optical (NLO) properties that we observed leads us to conclude that these doped monomers can be appropriate candidates in devices requiring good NLO properties., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Hartree-Fock (HF) and Density Functional Theory (DFT) were used to investigate the structural, optoelectronic, thermodynamic and nonlinear optical properties of two styrylquinoline monomers; the virgin styrylquinoline monomer (M1) and the derivative monomer (M2) with the NO 2 group. The results show that these two materials have good optoelectronic properties with respect to very high electric fields in particular from 3.50 × 109 Vm-1 up to 5.52 × 109Vm−1. In addition, the substitution of the H atom by the nitro group induces an increase in both ionization potential and electronic affinity, as well as a reduction in the fundamental electronic gap. The energy gap value of 3.82 eV for M1 and of 3.43 eV of M2, allows us to conclude that our molecules are semiconductors and find applications in the design of solar cells. The determination of thermodynamic properties has revealed thermodynamically stable materials with significant reactivity that are suitable for reactions with other compounds. Further, the high values of linear and nonlinear optical properties led us to conclude that these materials have very good linear and nonlinear optical properties and therefore can be used in telecommunication and signal processing. • The structural parameters and thermodynamic analysis have revealed thermodynamically stable materials. • The energy gap values of 3.82 eV for M1 and of 3.43 eV of M2, show that they are the semiconductor materials. • The two molecular systems exhibit good linear and nonlinear properties. • The reactivity of monomers containing styrylquinoline is improved by the substitution of the H atom by the nitro group. • Higher refractive index than glass can be used under strong electric fields of the order of 3.50 × 109 Vm-1 up to 5.52 × 109Vm−1. [ABSTRACT FROM AUTHOR]

Highlights: [•] UV–Vis absorption behavior of an hydroxy-quinoline derivative as inhibitor of Pim-1 kinase. [•] UV–Vis linear dichroism measurements on 7-nicotinoyl SQL aligned in stretched PVA. [•] Time dependent density functional theory (TD-DFT) calculations. [•] Orientation of transitions moments with respect to the long in-plane axis of 7-nicotinoyl SQL. [Copyright &y& Elsevier]

Abstract: Photophysical and photochemical properties of the novel bichromophoric covalently linked dyads SQmNp (m =2, 3, 4, 5), where 2-styrylquinoline (SQ) and 2-naphthol (Np) chromophoric groups are connected by dioxypolymethylene bridge –O-(CH2) m -O–, in comparison with model compounds 2-(4-methoxystyryl)quinoline MeOSQ and 3-methoxynapthol-2 MeONp, are investigated. There is no significant interaction between chromophores in the ground (S0) state. In the singlet excited (S1) state, the Forster resonance energy transfer (FRET) takes place from the Np to the SQ fragment that results in quenching of the Np-fragment fluorescence in the dyads. Calculated Forster radius (R 0) for the MeONp–MeOSQ donor–acceptor pair is equal to 3.8nm that exceeds the distance (R) between two chromophores even in the most elongated conformers of the dyads studied, and explains the efficient interaction between chromophores in the S1 state. The FRET efficiency depends on the bridge length and achieves maximal value (99.7%) in the dyad with three-methylene linking chain (m =3). The acidity of the dyad constituting fragments changes in opposite directions upon excitation; it decreases for the SQ fragment (which is a photobase) but increases for the Np fragment (which is a photoacid). The photoisomerization of the SQ fragment in the dyads occurs with the same quantum yields (∼0.5) as in the model MeOSQ and does not depend on the methylene bridge length. [Copyright &y& Elsevier]

A three-step approach to the synthesis of bichromophoric dyads of the general formula SQ-(CH)-Np (SQ is the 2-(4-oxystyryl)quinoline moiety, Np is the 3-oxy-2-naphthol moiety, n = 2, 4, 5) was developed from available reagents. [ABSTRACT FROM AUTHOR]

Successive molecular assembling in polymer chains furnished a series of the comb-shaped copolymers of 4-aminostyrene containing side styrylquinoline chromophore groups. Thermal, thermomechanical, spectroscopic, and luminescent properties of the polymers and low-molecular-weight model chromophores were studied. [ABSTRACT FROM AUTHOR]

In spite of significant progress in anti-HIV-1 therapy, current antiviral chemotherapy still suffers from deleterious side effects and emerging drug resistance. Therefore, the development of novel antiviral drugs remains a crucial issue for the fight against AIDS. HIV-1 integrase is a key enzyme in the replication cycle of the retrovirus since it catalyzes the integration of the reverse transcribed viral DNA into the chromosomal DNA. Efforts to develop anti-integrase drugs started during the early nineties, culminating with the recent approval of Raltegravir. The discovery and the development of the styrylquinoline inhibitor class was an important step in the overall process. In this review we have described the key synthetic issues and the structure-activity relationship of this family of integrase inhibitors. Crystallographic and docking studies that shed light on their mechanism of action are also examined. [ABSTRACT FROM AUTHOR]

Abstract: HIV-1 integrase inhibitory activity data of styrylquinoline derivatives have been subjected to 3D-QSAR study by molecular shape analysis (MSA) technique using Cerius2 version 4.8 software (Accelrys). For the selection of test set compounds, initially a QSAR analysis was done based on topological and structural descriptors and K-means clustering technique was used to classify the entire data set (n =36). Clusters were formed from the factor scores of the whole data set comprising of topological and structural descriptors without the biological activity, and based on the clusters, the data set was divided into training and test sets (n =26 and n =10, respectively) so that all clusters are properly represented in both training and test sets. In the molecular shape analysis, the major steps were (1) generation of conformers and energy minimization; (2) hypothesizing an active conformer (global minimum of the most active compound); (3) selecting a candidate shape reference compound (based on active conformation); (4) performing pair-wise molecular superimposition using maximum common subgroup [MCSG] method; (5) measuring molecular shape commonality using MSA descriptors; (6) determination of other molecular features by calculating spatial and conformational parameters; (7) selection of conformers; (8) generation of QSAR equations by standard statistical techniques. The best model obtained from stepwise regression and GFA techniques shows 51.6% predicted variance (leave-one-out) and 57.3% explained variance. In case of FA–PLS regression, the best relation shows 54.0% predicted variance and 57.9% explained variance. The R 2 pred and R 2 test values for the GFA derived model are 0.611 and 0.664, respectively, while the best FA–PLS model has R 2 pred and R 2 test values of 0.602 and 0.656, respectively. These models show the importance of Jurs descriptors (total polar surface area, relative polar surface area, relative hydrophobic surface area, relative positive charge), fraction area of the molecular shadow in the XZ plane (ShadowXZfrac), common overlap steric volume and the ratio of common overlap steric volume to volume of individual molecules. Statistically reliable MSA models obtained from this study suggest that this technique could be useful to design potent HIV-1 integrase inhibitors. [Copyright &y& Elsevier]

Isomeric azidostyrylquinolines with a 4-azidostyryl group in position 2 or 4 of the quinoline ring have been synthesized. In the neutral form the azidostyrylquinolines absorb in the near UV but the protonated species absorb in the short wavelength region of the visible spectrum. In both forms the azides are lightsensitive and decompose under the influence of light with a quantum yield close to 1. [ABSTRACT FROM AUTHOR]

Highlights: [•] Simple methods for the synthesis of novel fluoroquinolines based on 2,3,4-trifluoronitrobenzene have been developed. [•] 6,7-Difluoro substituted Zn(II) complex showed blue shift of the emission peak in comparison with non-fluorinated chelate. [•] 6,7-Difluoro substituted 8-hydroxy-2-styrylquinoline showed red shift of the emission peak in comparison with non-fluorinated ligand. [Copyright &y& Elsevier]

Styrylquinoline is a quinoline molecule linked to phenyl rings with an unsaturated ethylene linker, resulting in a flat and rigid conformation. The synthesis of the molecule was reported almost a century ago but was not much explored due to its adverse toxicity and poor selectivity. In the last two decades, a plethora of work was reported related to the synthesis and antiretroviral activity of several styrylquinoline derivatives. Later, other activities such as antimicrobial and anticancer abilities of these derivatives were also reported. In this review, we summarize the diverse steps of the development and analyze the spectrum of the activity of styrylquinolines and their utilization in drug design. Styrylquinolines are extensively explored for new pharmacological activities in recent years and this makes the moiety gain more visibility as a potential drug candidate and lead molecule in medicinal chemistry. The data obtained in vitro and ex vivo shed light on their different mechanism of action. Styrylquinoline has proved to be a potential lead molecule in medicinal chemist's toolkit due to the exploration of a variety of avenues of its activity as a drug candidate., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)