Search

Benzoxazoles and benzothiazoles are a class of aromatic heterocyclic compounds having similar ring structures, in which a benzene ring is fused to the 4 and 5 positions of the 1,3-oxazole and 1,3-thiazole rings respectively. They constitute an interesting class of organic compounds due to their powerful and significant biological, agrochemical, pharmaceutical and physicochemical activities. Indeed, benzoxazole and benzothiazole derivatives possess a wide range of applications, such as: anticancer, anti-inflammatory, antioxidant, anticonvulsant, antitubercular, antifungal, pesticidal, anticorrosive, complexing properties and so on. The synthesis of benzoxazole and benzothiazole derivatives has attracted much attention from several researchers across the world and numerous synthetic methods have been developed to access these compounds over the past decades. In this review, we present new and recent synthetic strategies, as well as some biological properties of benzoxazole and benzothiazole derivatives. [ABSTRACT FROM AUTHOR]

One pot, rapid and green preparation of 2-aryl-1,3-benzoxazole and their derivatives via the reaction of o-amino phenol and substituted aryl aldehydes by using amla fruit extract at room temperature or under microwave radiation. Amla fruit extract is a biocatalyst associated with low-cost, inexpensive, non-volatile, and environmentally friendly. The prepared catalyst shows many chemical, phytochemical, and anti-oxidant constituents, which are unfavorable to increase the acidic contents of water extract. The noteworthy benefits of this process are simple, easy methodology, an excellent yield of product, minimum time of reaction, ease of separation, easy work, and green catalyst. The prepared compound where characterized by analytical or spectroscopic techniques such as FT-IR (infrared) spectrum, H1-NMR, C13-NMR, and LC-MS (Mass) analysis. [ABSTRACT FROM AUTHOR]

Renin inhibitors derived from natural ingredients often belong to the saponin or polyphenol chemical class. Pegagan (Centella asiatica) is a natural plant in Indonesia that contains saponins and polyphenols. The active compounds of Pegagan include asiaticoside, madasiatic acid, madecassoside, madecassic acid, and asiatic acid. This study investigates the possible renin-inhibitory properties of phytochemicals from Centella asiatica using in-silico molecular docking. Using AutoDock v4.2.6, up to five C. asiatica compounds were docked with 2V0Z Renin with Inhibitor 10 (Aliskiren) in human subjects (Homo sapiens 6LU7). These compounds included asiaticoside, madasiatic acid, madecassoside, madecassid acid, and asiatic acid. SwissADME was used to evaluate these drugs' pharmacokinetic characteristics. The molecular docking results of 5 test ligands obtained affinity energy values from -8.7 kcal/mol to -10.4 kcal/mol. In contrast, the affinity energy value for the comparison ligand (aliskiren) is -9.0 kcal/mol. Madecasosside has an affinity energy value of -10.4 kcal/mol, asiaticoside of -9.6 kcal/mol and asiatic acid of -9.2 kcal/mol. Based on this energy affinity value, the active compound C. asiatica has the potential as a renin inhibitor. Pharmacokinetic analysis revealed that asiatic acid, madecassic acid, madasiatic acid, and asiatic acid have good pharmacokinetic properties. It may be concluded based on in silico molecular docking and pharmacokinetics investigation that the molecule most strongly suggested for additional in vitro renin inhibitor research was asiatic acid. Keywords: Renin Inhibitor, Centella asiatica, Molecular Docking. [ABSTRACT FROM AUTHOR]

A facile, efficient, and eco‐friendly strategy to access benzoxazole heterocyclic products has been accomplished through oxidation of catechols followed by condensation/cyclization/aromatization sequences. This process is catalyzed by nanostructured iron(III)‐porphyrin complex to form desired benzoxazole derivatives at room temperature under air condition. The procedure is widely applicable to diverse amines, and can provide the heterocyclic products in a scalable fashion, as well. One of the most significant types of oxidizing agents in nature is the iron‐porphyrin complexes (0.1 mol‐%), existing in the structure of hemoglobin. They have benefits such as low toxicity and high oxidation potential for many substrates. [ABSTRACT FROM AUTHOR]

Owing to its high reactivity and commercial availability, 2-cyanoacetohydrazide can be utilized as a versatile and appropriate intermediate for synthesis of a broad variety of heterocyclic compounds. Thus, 2-cyanoacetohydrazide and 2-(1,3-dioxoisoindolin-2-yl) acetyl chloride were used as starting materials for construction of new heterocyclic compounds bearing 1,3-dioxoisoindoline moiety. The newly synthesized compounds were recognized by elemental analyses and spectral data (IR, 1H-NMR, and 13C-NMR spectra). The synthesized compounds were screened for their anti-proliferative activity against two human epithelial cell lines; breast (MCF-7) and liver (HepG2) as well as to normal fibroblasts (WI-38). The data showed distinctly that compounds 1 and 12 presented promising in-vitro anti-proliferative activity against two cell lines (MCF-7 and HepG2) without harming normal fibroblasts. [ABSTRACT FROM AUTHOR]

A highly efficient, simple and rapid method for the preparation of various 2-aminobenzoxazoles and other benzoxazole derivatives using a catalytic amount of poly (ethylene glycol)-bound sulfonic acid (PEG-SO3H) is described. PEG-SO3H is found to be an economical and reusable catalyst with low catalytic loading. The percent yield was found to be satisfactory, experimental set up and purification of final products are facile and easy.

Modifying the position and numbers of lateral fluorine substituent is a common method to design and adjust the mesophase of liquid crystal compounds. Here, a series of 2-(2,2ʹ-difluoro-4ʹ-alkoxy-1,1ʹ-biphenyl-4-yl)-5-substituted benzoxazole with both non-polar (H, CH3) and polar (NO2) groups (coded as nPF(2)PF(2)Bx) is synthesised and characterised. All of the compounds show a conspicuous inter-ring twist angle of 38° compared with corresponding reference compounds I and II which are calculated by density functional theory method, and it is interesting to note that the final compounds nPF(2)PF(2)Bx show only nematic mesophase during heating or cooling. Meanwhile, the UV-vis absorption bands and photoluminescence emission peaks both display remarkable blue-shifted. The aforementioned results reveal that lateral difluoro substituents play a key role to stable the nematic mesophase by increasing the dihedral angle of biphenyl. [ABSTRACT FROM AUTHOR]

Background: Due to the biological importance of the benzoxazole derivatives, some 1- (benzo[d]oxazol-2-yl)-3,5-diphenyl-formazans 4a-f were synthesized and screened for in-silico studies and in-vitro antibacterial activity., Methods: The benzo[d]oxazole-2-thiol (1) was prepared by reacting with 2-aminophenol and carbon disulfide in the presence of alcoholic potassium hydroxide. Then 2-hydrazinylbenzo[d] oxazole (2) was synthesized from the reaction of compound 1 with hydrazine hydrate in the presence of alcohol. Compound 2 was reacted with aromatic aldehydes to give Schiff base, 2-(2- benzylidene-hydrazinyl)benzo[d]oxazole derivatives 3a-f. The title compounds, formazan derivatives 4a-f, were prepared by a reaction of benzene diazonium chloride. All compounds were confirmed by their physical data, FTIR, 1 H-NMR, and 13 CNMR spectral data. All the prepared title compounds were screened for in-silico studies and in-vitro antibacterial activity on various microbial strains., Results: Molecular docking against the 4URO receptor demonstrated that molecule 4c showed a maximum dock score of (-) 8.0 kcal/mol. MD simulation data reflected the stable ligand-receptor interaction. As per MM/PBSA analysis, the maximum free binding energy of (-) 58.831 kJ/mol was exhibited by 4c. DFT calculation data confirmed that most of the molecules were soft molecules with electrophilic nature., Conclusion: The synthesized molecules were validated using molecular docking, MD simulation, MMPBSA analysis, and DFT calculation. Among all the molecules, 4c showed maximum activity. The activity profile of the synthesized molecules against tested micro-organisms was found to be 4c>4b>4a>4e>4f>4d., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Fluorinated aromatics is generally chosen as mesogenic cores to design novel liquid crystal compounds. Here, a series of benzoxazole derivatives with laterally multifluorinated biphenyl units, 2-(3′,3-difluoro −4′-alkoxy-1,1′-biphenyl-4-yl)-benzoxazole derivatives (coded as nPF(3)PF(3)Bx), are synthesized and characterized, where methyl and nitro moieties are selected as terminal groups to investigate the effects of different polar substituents on the liquid crystal properties. The compounds nPF(3)PF(3)Bx show enantiotropic mesophases with mesophase ranges of 0-40°C and 0-63°C on heating and cooling for hydrogen-terminated derivatives (nPF(3)PF(3)BH), 43-93°C and 54-123°C for methyl-terminated ones (nPF(3)PF(3)BM), 60-108°C and 74-152°C for nitro terminated ones (nPF(3)PF(3)BN), respectively. They exhibit photoluminescence emission peaks at 390-392 nm and UV-vis absorption bands with maxima at 327-330 nm, respectively. The results reveal that lateral multifluoro substituents lead to a decrease in melting/clearing points, while electron-withdrawing terminal nitro moiety results in increases in both melting point and mesophase range. [ABSTRACT FROM AUTHOR]

Mast cells are central regulators of allergic inflammation that function by releasing various proallergic inflammatory mediators, including histamine, eicosanoids and proinflammatory cytokines. Occasionally, bacterial infections may initiate or worsen allergic inflammation. A number of studies have indicated that activation of lipoxygenase in mast cells positive regulates allergic inflammatory responses by generating leukotrienes and proinflammatory cytokines. In the present study, the effects of benzoxazole derivatives on the lipopolysaccharide (LPS)‑induced expression of proinflammatory cytokines, production of histamine and surface expression of co‑stimulatory molecules on bone marrow‑derived mast cells (BMMCs) were studied. The benzoxazole derivatives significantly reduced the expression of interleukin (IL)‑1β, IL‑6, IL‑13, tumor necrosis factor‑α, perilipin (PLIN) 2, and PLIN3 in BMMCs treated with LPS. Furthermore, histamine production was suppressed in BMMCs treated with LPS, or treated with phorbol‑12‑myristate‑13‑acetate/ionomycin. Benzoxazole derivatives marginally affected the surface expression of cluster of differentiation (CD)80 and CD86 on BMMCs in the presence of LPS, although LPS alone did not increase the expression of those proteins. Therefore, benzoxazole derivatives inhibited the secretion of proinflammatory cytokines in mast cells and may be potential candidate anti‑allergic agents to suppress mast cell activation. [ABSTRACT FROM AUTHOR]

A new series of substituted- N -(3,4-dimethoxyphenyl)-benzoxazole derivatives 13a – 13p was synthesized and evaluated in vitro for their COX (I and II) inhibitory activity, in vivo anti-inflammatory and ulcerogenic potential. Compounds 13d , 13h , 13k , 13l and 13n exhibited significant COX-2 inhibitory activity and selectivity towards COX-2 over COX-1. These selected compounds were screened for their in vivo anti-inflammatory activity by carrageenan induced rat paw edema method. Among these compounds, 13d was the most promising analogs of the series with percent inhibition of 84.09 and IC 50 value of 0.04 µM and 1.02 µM (COX-2 and COX-1) respectively. Furthermore, ulcerogenic study was performed and tested compounds ( 13d , 13h , 13k , 13l ) demonstrated a significant gastric tolerance than ibuprofen. Molecular docking study was also performed with resolved crystal structure of COX-2 to understand the binding mechanisms of newly synthesized inhibitors in the active site of COX-2 enzyme and the results were found to be concordant with the biological evaluation studies of the compounds. These newly synthesized inhibitors also showed acceptable pharmacokinetic profile in the in silico ADME/T analyses. [ABSTRACT FROM AUTHOR]

For finding novel bioactive compounds with significant antifungal activities, 17 novel benzoxazole derivatives containing a 1,2,3-triazole moiety were synthesized by the copper(II) acetylacetonate-catalyzed cyclization reaction between 2-aminophenol derivatives and 1 H-1,2,3-triazole-4-carbaldehyde derivatives ( 4a), which were prepared through three steps using aromatic amine as the starting material. Antifungal activities of the prepared compounds were evaluated against Botrytis cinerea (BC) and Fusarium Verticillium (FV). The test results indicated that compounds 5b, 5c, 5h, and 5n show good inhibitory effects on fungi. The preliminary structure-activity relationship is also discussed. [ABSTRACT FROM AUTHOR]

A highly efficient, simple and rapid method for the preparation of various 2-aminobenzoxazoles and other benzoxazole derivatives using a catalytic amount of poly (ethylene glycol)-bound sulfonic acid (PEG-SO 3 H) is described. PEG-SO 3 H is found to be an economical and reusable catalyst with low catalytic loading. The percent yield was found to be satisfactory, experimental set up and purification of final products are facile and easy. [ABSTRACT FROM AUTHOR]

A growing number of studies have demonstrated that interleukin (IL)-6 plays pathological roles in the development of chronic inflammatory disease and autoimmune disease by activating innate immune cells and by stimulating adaptive inflammatory T cells. So, suppression of IL-6 function may be beneficial for prevention and treatment of chronic inflammatory disease. This study reports that a series of synthetic derivatives of benzoxazole have suppressive effects on IL-6-mediated signaling. Among 16 synthetic derivatives of benzoxazole, the compounds 4 , 6 , 11 , 15 , 17 , and 19 showed a strong suppressive activity against IL-6-induced phosphorylation of signal transducer and activator of transcription (STAT) 3 by 80–90%. While the cell viability was strongly decreased by compounds 11 , 17 , 19 , the compounds 4 , 6 , and 15 revealed less cytotoxicity. We then examined the effects of the compounds on inflammatory cytokine production by CD4+ T cells. CD4+ T cells were induced to differentiate into interferon (IFN)-γ-, IL-17-, or IL-4-producing effector T cells in the presence of either the compound 4 or the compound 7 . While the inactive compound 7 had no significant effect on the cytokine production by effector T cells, the active compound 4 strongly suppressed the production of inflammatory cytokines IFN-γ and IL-17, and also inhibited allergic inflammatory cytokines IL-4, IL-5, and IL-13 produced by effector Th2 cells. These results suggest that a benzoxazole derivative, compound 4 effectively suppresses IL-6-STAT3 signaling and inflammatory cytokine production by T cells and provides a beneficial effect for treating chronic inflammatory and autoimmune disease. [ABSTRACT FROM AUTHOR]

The purpose of the article is to promote and facilitate prediction of antifungal activity of the investigated series of benzoxazoles against Candida albicans. The clinical importance of this investigation is to simplify design of new antifungal agents against the fungi which can cause serious illnesses in humans. Quantitative structure activity relationship analysis was applied on nineteen benzoxazole derivatives. A multiple linear regression (MLR) procedure was used to model the relationships between the molecular descriptors and the antifungal activity of benzoxazole derivatives. Two mathematical models have been developed as a calibration models for predicting the inhibitory activity of this class of compounds against Candida albicans. The quality of the models was validated by the leave-one-out technique, as well as by the calculation of statistical parameters for the established model. [Projekat Ministarstva nauke Republike Srbije, br. 172012 i br. 172014]

Based on benzoxazole and benzothiazole scaffold as an important pharmacophore, two series of 2-(aryloxymethyl) benzoxazole and benzothiazole derivatives were synthesized and their antifungal effects against eight phytopathogenic fungi were evaluated. Compounds 5a, 5b, 5h, and 5i exhibited significant antifungal activities against most of the pathogens tested. Especially 5a, 5b, 5h, 5i, 5j, and 6h inhibited the growth of F. solani with IC50 of 4.34–17.61 μg/mL, which were stronger than that of the positive control, hymexazol (IC50 of 38.92 μg/mL). 5h was the most potent inhibitor (IC50 of 4.34 μg/mL) against F. Solani, which was about nine times more potent than hymexazol. Most of the test compounds displayed significant antifungal effects against B. cinerea (IC50 of 19.92–77.41 μg/mL), among them, 5a was the best one (IC50 of 19.92 μg/mL). The structure-activity relationships (SARs) were compared and analyzed. The result indicates that the electron-drawing ability and position of the substituents have a significant impact on biological activities. Furthermore, docking studies were carried out on the lipid transfer protein sec14p from S. cerevisiae, and preliminarily verified the antifungal activities. Taken together, these results provide 2-(phenoxymethyl)benzo[d]oxazole as an encouraging framework that could lead to the development of potent novel antifungal agents.

In the present work, a quantitative relationship between the lipophilicity and antifungal activity of some benzoxazole derivatives against Candida albicans was investigated by using QSAR (quantitative structure-activity relationship) analyses. The descriptors which describe numerically the lipophilicity, logP, were calculated using Chem-Office Software version 7.0. The linear correlation between the minimal inhibitory concentration (log1/cMIC) and lipophilicity descriptors was investigated. The best QSAR model predicting the antifungal activity of the investigated series of benzoxazole was developed. The results are discussed on the basis of statistical data. High agreement between theoretical and experimental inhibitory values was obtained. The results of this study indicate that the lipophilicity parameter has a significant effect on antifungal activity of this class of compounds, which can be very useful in the design of new biologically active molecules.

Myeloid differentiation protein 2 (MD2), a key TLR4 adaptor protein for sensing LPS, plays an important role in inflammatory process and has been identified as a promising target for the treatment of a variety of inflammatory diseases. In our study, a series of benzoxazolone derivatives were synthesized, characterized and tested for anti-inflammatory activity in vitro. The compounds 3c, 3d and 3g demonstrated the greatest anti-inflammatory activity against IL-6 with IC 50 values of 10.14±0.08, 5.43±0.51 and 5.09±0.88 μM, respectively. Furthermore, the bis-ANS displacement assay revealed that these compounds competitively inhibited the binding between the probe bis-ANS and the MD2 protein. The most active compound 3g, revealed a directly bind with MD2 protein via Arg90 binding and a dissociation constant value of 1.52×10 -6  mol L -1 as determined by the biological layer interference (BLI) assay. Our finding suggested that compounds 3g could be a promising lead compound as MD2 inhibitor for further anti-inflammatory agent development., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

In the present work we calculate structural parameters, vibrational spectra (IR, 1 H NMR and UV–Visible Absorption) and corresponding mode of vibrational assignments of two ligands derived from benzoxazole; L 1 : 2-(5-(trifluoromethylpyridin-2-yl)-benzoxazole and L 2 : 2-(5-methylpyridin-2-yl)-benzoxazole at B3LYP/6-311++G** level, in the gas phase. The HOMO and LUMO study is used to determine the charge transfer within the molecules. Reactivity descriptors such as ionization energy, electronic affinity, global hardness, global softness, electrophilicity, nucleophilicity and condensed Fukui functions using NBO population analysis are also determined to predict the reactivity of L 1 and L 2 . The calculated geometrical parameters are in good agreement with those of similar benzoxazole derivatives. Theoretical frequencies assignments confirmed the experimental ones of these benzoxazole derivatives. [ABSTRACT FROM AUTHOR]

The title compound 2-(2-hydroxyphenyl)benzo[d]oxazole-6-carbaldehyde (1a) was synthesized and characterized by single-crystal X-ray diffraction. Compound1apossesses intramolecular C–H···O and O–H···N hydrogen bonds, which generate S(5) and S(6) rings, respectively. Intermolecular π–π stacking is observed in the crystal structure, which links a pair of molecules into a cyclic centrosymmetric dimer. The crystal structure is further stabilized by three different intermolecular C–H···O hydrogen bonds, which link the molecules into a continuous three-dimensional framework. Its spectroscopic properties and complementary density functional theory (DFT) calculations are also reported. [ABSTRACT FROM AUTHOR]

By modifying the molecular dipole moments with lateral monofluorine substituent, improved mesophase stabilities were obtained for novel benzoxazole derivatives, 2-(4ʹ-alkoxy-3-fluorobiphenyl-4-yl)-benzoxazole liquid crystals (coded asnPPF(3)Bx). The series ofnPPF(3)Bxwith lateral monofluorine substituent ortho to benzoxazole group have larger calculated dipole moments by about 2 D than the corresponding fluorine-substituted analogs (compounds I) with lateral monofluorine ortho to alkoxy group; it is interesting to note that they show lower melting and clearing points but better mesophase stability with wider mesophase ranges for the molecules with both polar (NO2, Cl) and nonpolar (CH3, H) terminal groups. Meanwhile, compoundsnPPF(3)Bxshow greater red-shifted photoluminescence emissions than compounds I, which suggest that π–π interaction between molecules is reinforced by the enhanced dipole–dipole interaction caused by increased dipole moments. These results suggest that modification of the molecular dipole moment is an effective method to improve the mesophase stability of the classical mesogenic compounds. [ABSTRACT FROM PUBLISHER]

[Display omitted] • A series of benzoxazole derivatives were designed and synthesized as H 3 R ligands. • Compound 8d showed high affinity for H 3 R, low affinities for ten other off-target receptors, and negligible effects on hERG. • Compound 8d exerted dose-dependent antinociceptive effects in the formalin-induced pain and chronic constriction injury (CCI) models. • Compound 8d exhibited an excellent safety profile in acute toxicity test and had a favorable drug-like pharmacokinetic profile. To discover effective analgesics, we summarize the synthesis, optimization, and pharmacological anti-nociceptive effects of a novel series of benzoxazole derivatives targeting H 3 receptor (H 3 R). The new benzoxazoles were assayed in vitro for histamine H 3 R and H 1 R binding affinity. The best compound 8d (2-methyl-6-(3-(4-methylpiperazin-1-yl)propoxy)benzo[ d ]oxazole) exhibited high affinity for H 3 R (K i = 19.7 nM), high selectivity for ten other off-target receptors, and negligible effects on human ether-a-go-go-related gene (hERG, cardiac ion channel). In rodent animals, compound 8d dose-dependently reversed formalin-evoked pain (Phase I, ED 50 = 6.0 mg/kg; Phase II, ED 50 = 7.8 mg/kg) and CCI-induced neuropathic pain (chronic constriction injury, ED 50 = 15.6 mg/kg). Furthermore, compound 8d showed an excellent safety profile in acute toxicity test (LD 50 > 2000 mg/kg) with a therapeutic index (TI = LD 50 /ED 50) > 250 and showed a desirable drug-like pharmacokinetic profile. Above characteristics indicate that compound 8d represents a promising candidate analgesic for the treatment of neuropathic pain. [ABSTRACT FROM AUTHOR]

Benzoxazole derivatives, an important type of heterocyclic compounds, have attracted significant interest in photonics and electronics since they are highly efficient luminophores with high photo-stability. The electrochemistry and electrogenerated chemiluminescence (ECL) of benzoxazole derivatives were reported and the substituent effects on the electrochemical and ECL properties of benzoxazole derivatives were investigated in an acetonitrile:benzene (v:v = 1:1) solvent for the first time. The studied derivatives contain a 2-biphenyl benzoxazole moiety with the substituents (–CH 3 , –Cl, and –NO 2 groups) at the 5-position of the benzoxazole ring and the alkoxy chains (C n H 2 n +1 , n = 2–10) at the 4′-position of the biphenyl ring. The electrochemical and ECL behavior of benzoxazole derivatives were found to be dependent on the nature of the substituents at the 5-position of the benzoxazole ring but independent on the alkoxy chain length at 4′-position of biphenyl moiety. Under ion annihilation conditions, 5B–H (2-(4′-pentyloxy-biphenyl-4-yl)-benzoxazole), 5B–Me (2-(4′-pentyloxy- biphenyl-4-yl)-5-methylbenzoxazole), and 5B–Cl (2-(4′-pentyloxy-biphenyl-4-yl)-5-chlorobenzoxazole), display high ECL blue emission (ECL efficiencies are 0.51, 0.54, and 0.78 for 5B–H, 5B–Me, and 5B–Cl, respectively), while 5B-NO 2 (2-(4′-pentyloxy-biphenyl-4-yl)-5-nitrobenzoxazole) does low ECL emission. In the presence of benzoyl peroxide, four derivatives exhibit strong ECL blue emissions. The results provide important electrochemical and ECL information of benzoxazole derivatives as well as their structure–properties relationships for future research. [ABSTRACT FROM AUTHOR]

N -(2-Chloro-phenyl)-2-halo-benzamides (halo=I/Br/Cl) as substrates were used for the one-pot synthesis of 2-arylbenzoxazole derivatives via copper-catalyzed intermolecular C–N/intramolecular C–O couplings with primary amines. This aryl amination offers clean reaction conditions and easy work-up in good yields by using CuI as catalyst, readily available 8-hydroxyquinoline as ligand, K 3 PO 4 as base, DMF as solvent. [ABSTRACT FROM AUTHOR]

In view of their expected anticonvulsant activity, some novel derivatives of 5-chloro-2-substituted sulfanylbenzoxazoles ( 5- 15f) were synthesized and evaluated for their anticonvulsant activity against pentylenetetrazole-induced seizures in mice. The molecular docking was performed for all the synthesized compounds to assess their binding affinities to KCNQ2 receptor in order to rationalize their anticonvulsant activities in a qualitative way. The data obtained from the molecular modeling were correlated with that obtained from the biological screening. These data revealed that compounds 15f, 7c, 15b, and 15d showed the highest binding affinities toward KCNQ2 receptor along with the highest anticonvulsant activities in experimental mice. The highest active compounds showed relative potencies of 0.98, 0.94, 0.91, and 0.83, respectively, in comparing to phenobarbital sodium. [ABSTRACT FROM AUTHOR]

Energies and oscillator strengths of vertical transitions for various rotameric and tautomeric species of 2-(2′-hydroxyphenyl)benzoxazole (HBO), 2,5-bis(2-benzoxazolyl)phenol (DBP) and 2,5-bis(2-benzoxazolyl)hydroquinone (BBHQ) have been calculated in the ground and first excited states with the use of TDDFT methods. The TDDFT results demonstrate good correspondence to the frequencies of absorption and fluorescence bands of the benzoxazoles reported for measurements in supersonic jets and solution, but fail to predict relative energies of the enol and keto tautomers of DBP and BBHQ in the excited state. Low intensity of the fluorescence bands attributed to the conformations of HBO and DBP that do not undergo excited state proton transfer is shown to be caused by low concentrations of the conformations in the ground state. For the three compounds large-amplitude twisting of the keto tautomer is found to be one of radiationless processes resulting in decrease of the fluorescence with a large Stokes shift. [ABSTRACT FROM AUTHOR]

Abstract: The energetic study of benzoxazole, 5-chloro-2-methylbenzoxazole, and 2-chlorobenzoxazole, in condensed and gaseous states, has been developed using experimental techniques and computational approaches. The values of the standard (p°=0.1MPa) molar enthalpy of formation, at T =298.15K, of crystalline benzoxazole (36.0±2.0)kJ·mol−1 and 5-chloro-2-methylbenzoxazole (145.6±2.2)kJ·mol−1 and liquid 2-chlorobenzoxazole (52.5±3.0)kJ·mol−1 were determined from the corresponding experimental standard molar energy of combustion in oxygen, −(3432.1±1.7)kJ·mol−1, −(3883.0 2.0)kJ·mol−1, and −(3298.0±2.8)kJ·mol−1, respectively , measured by static or rotating-bomb combustion calorimetry. At T =298.15K, the standard (p°=0.1MPa) molar enthalpy of sublimation of benzoxazole and 5-chloro-2-methylbenzoxazole and of vaporization of 2-chlorobenzoxazole, (69.2±0.8) kJ·mol−1, (82.4±2.2) kJ·mol−1, and (56.3±1.6) kJ·mol−1 respectively, were determined by a direct method, using the vacuum drop microcalorimetric technique. From the latter values and from the enthalpies of formation of the condensed compounds, the standard (p°=0.1MPa) enthalpies of formation of the gaseous compounds have been calculated. Standard ab initio molecular orbital calculations were performed using the G3(MP2)//B3LYP composite procedure and several working reactions in order to derive the standard molar enthalpy of formation of the three compounds. There exists a good agreement between the experimental and the computational data. [Copyright &y& Elsevier]

Abstract: Infrared spectra of solid state 2-(2′-hydroxyphenyl)benzoxazole, 2,5-bis(2-benzoxazolyl)phenol and 2,5-bis(2-benzoxazolyl)hydroquinone were studied in the region 400–4000cm−1. The measured spectra were compared with the results of density functional theory calculations of normal modes performed for different conformations of the isolated molecules. The calculated frequencies and intensities are in good agreement with the experimental values except the region 670–780cm−1 which comprises OH torsion modes, CH out-of-plane bending vibrations and torsions of the aromatic and oxazole rings. The experimental infrared spectra can be well simulated by the spectral patterns of rotamers possessing OH⋯N intramolecular hydrogen bonds. In the case of 2,5-bis(2-benzoxazolyl)phenol a number of bands are assigned to the vibrations of the conformer formed by rotation of the non-hydrogen-bridged benzoxazole moiety. [Copyright &y& Elsevier]

We synthesized liquid crystalline 2-phenylbenzothiazole derivatives and investigated their charge carrier transport properties by time-of-flight experiments. These materials show less ordered phases such as smectic A, smectic C, and nematic phases at temperature range lower than 100°C, and their mobility was relatively small, from 10-5 cm2/Vs to 10-4 cm2/Vs. In addition, the mobility depends on temperature, while it did not depend on electric fields. According to these results, we estimated the eneregy distribution of density of states responsible for condition, σ of Gaussian width, to be 78 ∼ 118 meV. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis, structures, electrochemistry, and photophysics of a series of cyclometalated iridium(III) complexes based on benzoxazole derivatives and different β-diketonate ligands are reported. These complexes have a general formula C∧N2Ir(LL′) [where C∧N is a monoanionic cyclometalating ligand; 2-phenylbenzoxazolato (pbo), 2-(4-chlorophenyl)benzoxazolato (cpbo), 2-phenyl-5-chlorobenzoxazolato (pcbo), 2-(3,5-difluorophenyl)benzoxazole (fpbo), or 2-(2-naphthyl)benzoxazolato (nbo), and LL′ is an ancillary ligand; acetylacetonate (acac), dibenzoylmethanate (dbm), or 1,1,1,5,5,5-hexafluoroacetylacetonate (hfacac)]. The complexes (pcbo)2Ir(acac) (3), (dfpbo)2Ir(acac) (4), (cpbo)2Ir(dbm) (7), (dfpbo)2Ir(dbm) (8), and (dfpbo)2Ir(hfacac) (9) have been structurally characterized by X-ray crystallography. All of the complexes show reversible oxidation between 0.45 and 1.07V, versus Fc/Fc+, and have short luminescence lifetime (τ =0.1–1.3μs) at room temperature. Except complex 9, the radiative decay rate (k r) and nonradiative decay rate (k nr) of the (C∧N)2Ir(LL′) complexes have been determined by using the lifetime and quantum efficiency. The k r ranges between 2.0×103 and 3.0×105 s−1 and k nr spans a narrower range of values (5.0×105 to 7.0×106 s−1). [Copyright &y& Elsevier]

Abstract: 5-HT3 receptor is an attractive target for the development of therapeutic agents for use in brain, heart and cancer diseases, and imaging agents for use in biomedical imaging technique PET. Benzoxazole derivatives are a novel class of 5-HT3 receptor partial agonists with high binding affinity. Carbon-11 labeled benzoxazole derivatives have been synthesized as new potential PET radioligands for imaging 5-HT3 receptor. The target tracers were prepared by N-[11C]methylation of their corresponding precursors using [11C]CH3OTf and isolated by HPLC purification procedure in 40–50% radiochemical yields, which were decay corrected to the end of bombardment (EOB), based on [11C]CO2. The overall synthesis time was 20–25min from EOB. The radiochemical purity was >99%, and specific activity was in a range of 74–111GBq/μmol at the end of synthesis (EOS). [Copyright &y& Elsevier]

Abstract: A series of N-(acridin-9-yl)-4-(benzo[d]imidazol/oxazol-2-yl) benzamides has been synthesized by the condensation of 9-aminoacridine derivatives with benzimidazole or benzoxazole derivatives. Condensation of 2-hydroxy naphthaldehyde with functionalized diamines leads to the formation of Schiff’s bases and not imidazole derivatives. All these compounds were characterized by correct FT-IR, 1H NMR, MS and elemental analyses. These compounds were screened for anti-inflammatory, analgesic and kinase (CDK-1, CDK-5 and GSK-3) inhibition activities. Compounds 11 and 7e(f) showed good anti-inflammatory (35.8% at 50mg/kg po) activity and good analgesic activity (60% at 50mg/kg po), respectively. Compound 3b showed significant in vitro activity against CDK-5 (IC50 =4.6μM) and CDK-1(IC50 =7.4μM) and compound 3a showed moderate CDK-5 inhibitory activity (IC50 =7.5μM). The other compounds showed moderate anti-inflammatory and analgesic activities. [Copyright &y& Elsevier]

Based on benzoxazole and benzothiazole scaffold as an important pharmacophore, two series of 2-(aryloxymethyl) benzoxazole and benzothiazole derivatives were synthesized and their antifungal effects against eight phytopathogenic fungi were evaluated. Compounds 5a, 5b, 5h, and 5i exhibited significant antifungal activities against most of the pathogens tested. Especially 5a, 5b, 5h, 5i, 5j, and 6h inhibited the growth of F. solani with IC50 of 4.34–17.61 μg/mL, which were stronger than that of the positive control, hymexazol (IC50 of 38.92 μg/mL). 5h was the most potent inhibitor (IC50 of 4.34 μg/mL) against F. Solani, which was about nine times more potent than hymexazol. Most of the test compounds displayed significant antifungal effects against B. cinerea (IC50 of 19.92–77.41 μg/mL), among them, 5a was the best one (IC50 of 19.92 μg/mL). The structure-activity relationships (SARs) were compared and analyzed. The result indicates that the electron-drawing ability and position of the substituents have a significant impact on biological activities. Furthermore, docking studies were carried out on the lipid transfer protein sec14p from S. cerevisiae, and preliminarily verified the antifungal activities. Taken together, these results provide 2-(phenoxymethyl)benzo[d]oxazole as an encouraging framework that could lead to the development of potent novel antifungal agents. [ABSTRACT FROM AUTHOR]

An abstract of the article "Elemental Sulfur Medicated Synthesis of Benzoxazoles, Benzothiazoles and Quinoxalines via Decarboxylative Coupling of 2-Hydroxy/mercapto/aminoanilines with Cinnamic Acids" by Tirumaleswararao Guntreddi, Rajeshwer Vanjari, and Saurabh Kumar.

An abstract of the article "Copper-Catalyzed Synthesis of Benzoxazoles via Tandem Cyclization of 2-Halophenols with Amidines" by A. R. Tiwari and B. M. Bhanage is presented.

A metal-free, convenient one-step strategy is presented proceeding at ambient temperature via a cross-dehydrogenative coupling of benzoxazole-thiones or bis(benzothiazoyl)disulfides. [ABSTRACT FROM AUTHOR]

The new cobalt-based heterogeneous catalyst is prepared by adsorbing in situ produced nitrogen-ligated cobalt(II) acetate complexes on commercially available SiO2 and subsequent pyrolysis at 800 °C for 2 h under N2 atmosphere. [ABSTRACT FROM AUTHOR]

The scalable, metal-free approach has a broad substrate scope. [ABSTRACT FROM AUTHOR]

Benzimidazoles, benzoxazoles, and benzothiazoles are prepared extremely rapidly. [ABSTRACT FROM AUTHOR]

The title reaction provides N-alkylated amines and amides in good yields and is applied to the synthesis of benzazoles. [ABSTRACT FROM AUTHOR]

The use of organic halides as oxidants to achieve the cross-dehydrogenative coupling reaction of two unfunctionalized heteroarenes (pyridines and benzoxazoles) with palladium catalyst is described. [ABSTRACT FROM AUTHOR]