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Oxazole, a five‐membered cyclic ring containing oxygen and nitrogen, displays diverse interactions and structural variations, enhancing its potential applications across various domains. Oxazole derivatives exhibit diverse pharmacological activities, including antidiabetic, anticonvulsant, anticancer, phosphodiesterase inhibition, antiprotozoal, and antibacterial effects, making them appealing to medicinal chemists. Their presence in naturally occurring pharmacologically active substances as well as synthetic medicines underscores their therapeutic potential. This review encompasses recent advancements in the biological activities of oxazole derivatives during the period of 2018–2023. The discussed activities include antitumor, central nervous system (CNS) modulation, antidiabetic, anti‐Alzheimer, antibacterial, and enzyme inhibitory effects. The review highlights the mechanisms of action of these compounds in various diseases, the most potent compounds along with their respective IC50/MIC (inhibitory concentration/minimum inhibitory concentration) values, and discusses the models utilized for quantifying their activity. Currently, there are eight FDA‐approved drugs bearing oxazole scaffolds available in the market. Analysis of the literature reveals that the antitumor activity of oxazole derivatives is particularly noteworthy among their various activities. The incorporation of phenyl, methoxyphenyl, or halogen‐substituted phenyl moieties significantly enhances therapeutic activities compared to reference drugs. The substitution flexibility at three positions of oxazole derivatives contributes to their spectrum of pharmacological activities. [ABSTRACT FROM AUTHOR]

We report the development of a four‐component electrochemical method for the synthesis of CF3‐oxazoles, utilizing alkynes and NaSO2CF3 in MeCN. The method leverages the simplicity and mildness of the reaction conditions, despite the inherent complexity of utilizing four distinct components through aminotrifluoromethylation of alkyne followed by in‐situ cyclization. Notably, in addition to MeCN solvent, the presence of residual water in the reaction mixture also contributed as a coupling partner. The synthesis involves a sequence of four controlled oxidation steps under constant potential with graphite electrodes, facilitated by the mediator TMEDA, highlighting the precision achievable in electrochemistry. [ABSTRACT FROM AUTHOR]

Oxazoles and Imidazoles are heterocyclic compounds with significant biological activities. The present study explores the pharmacological effects of some new oxazole and imidazole derivatives as potential COX-2 inhibitors. Docking studies of the compounds against targeted proteins COX-2 and TACE manifested good binding affinities for both the targets supporting their anti-inflammatory potential. Compounds (3F-A, 3F-B, N-A, N-B) were evaluated for in vivo anti-inflammatory effects by carrageenan-induced paw edema. Among all, compound N-A was found to be the most effective as it displayed most pronounced reduction in inflammation that was comparable to indomethacin. The in vivo tissue antioxidant activity was performed for estimation of the level of catalase, GSH, GST, and thiobarbituric acid in paw tissue. The results exhibited that targeted compounds improved the oxidative stress and restored the expression of enzymes. H &E staining revealed that aforesaid compounds displayed well-defined restoration of cellular damage. Compound NA exhibited maximum structural and functional preservation. Reduction in the expression of inflammatory markers was also analyzed by ELISA and maximum reduction in protein expression (COX-2 and TNF-a) was observed for compound N-B. Quantification of mRNA was done using PCR and a decrease in the expression of COX-2 mRNA level in treatment groups was depicted by all the new compounds but N-B showed maximum reduction in enzyme expression. All the results obtained from the present study have shown the significant anti-inflammatory potential of new compounds via the COX-2 inhibition pathway.

This review presents an outline of current advancements in the photochemical and electrochemical synthesis of oxazoles and isoxazoles. Oxazole and isoxazole are important building blocks for a variety of medicinally useful compounds. Therefore, the synthesis of these heterocycles via sustainable technologies is worth demanding. Photochemical and electrochemical are two among the few sustainable technologies. This review covers a brief discussion on reaction parameters like catalysts, substrates scope, reaction temperature, solvents, electrodes, electrolytes (in case of electrochemical process), light source (in case of photochemical process) for individual reaction. Detailed discussion on mechanistic insight for each reaction is also presented. Finally, summary, and future direction toward the development of effective electrochemical and photochemical methods for the reaction of oxazoles and isoxazoles is also presented. [ABSTRACT FROM AUTHOR]

A targeted metabologenomic method was developed to selectively discover terminal oxazole‐bearing natural products from bacteria. For this, genes encoding oxazole cyclase, a key enzyme in terminal oxazole biosynthesis, were chosen as the genomic signature to screen bacterial strains that may produce oxazole‐bearing compounds. Sixteen strains were identified from the screening of a bacterial DNA library (1,000 strains) using oxazole cyclase gene‐targeting polymerase chain reaction (PCR) primers. The PCR amplicon sequences were subjected to phylogenetic analysis and classified into nine clades. 1H−13C coupled‐HSQC NMR spectra obtained from the culture extracts of the hit strains enabled the unequivocal detection of the target compounds, including five new oxazole compounds, based on the unique 1JCH values and chemical shifts of oxazole: lenzioxazole (1) possessing an unprecedented cyclopentane, permafroxazole (2) bearing a tetraene conjugated with carboxylic acid, tenebriazine (3) incorporating two modified amino acids, and methyl‐oxazolomycins A and B (4 and 5). Tenebriazine displayed inhibitory activity against pathogenic fungi, whereas methyl‐oxazolomycins A and B (4 and 5) selectively showed anti‐proliferative activity against estrogen receptor‐positive breast cancer cells. This metabologenomic method enables the logical and efficient discovery of new microbial natural products with a target structural motif without the need for isotopic labeling. [ABSTRACT FROM AUTHOR]

In this research investigation, a total of eighteen diverse tetra- and penta-lateral cyclic compounds were synthesized. These included 1,3,4-thiadiazole, thiazolidin-4- one (via an alternative method), 1,2,4-triazole, carbothioamide, thiazole-4-one, azetidin-2-one, and oxazole. The synthesis procedure entailed a sequence of reactions. The thiazolidine-4-one 1 was obtained by reaction p-aminobenzoic acid with thiosemicarbazide, followed by treatment with p-tolualdehyde to produce Schiff base 2. Reaction Schiff base 2 with mercaptoacetic acid in dry benzene was carried out to produce thiazolidine-4-one 3. In another synthesis pathway, the esterification of p-nitro benzoic acid with ethanol in the presence of sulfuric acid was obtained to formation of compound 4. Compound 4 was subsequently reacted with thiosemicarbazide, yielding compound 5. Cyclization of compound 5 was then achieved using 4% sodium hydroxide solution. This formed the 1,2,4-triazole heterocycle, designated compound 6. Thiosemicarbazone 7-9 were prepared by reaction of thiosemicarbazide with different aldehydes. Additionally, 2-substituted1,3-thiazolidine-4-one derivatives 10-12 were synthesized through the reaction of thiosemicarbazone with chloroacetic acid in the presence of anhydrous sodium acetate. The Oxazole derivative 15 was obtained through a series of reactions starting with the reaction of p-amino benzoic acid with ethyl chloroacetate, resulting in compound 13. Compound 13 was then treated with urea to obtain compound 14, followed by a reaction with 4-phenyl phenacyl bromide to yield the final product, the Oxazole derivative 15. The 2-aminooxadiazole derivative 16 was synthesized by reaction urea with 4-bromoacetophenone which was reacted with 4- bromobenzaldehyde to produce Schiff base derivative 17. Finally, β-lactam 18 is obtained through reaction Schiff base with chloroacetyl chloride in the presence of triethyl amine. FT-IR, 1H-NMR, and 13C-NMR spectroscopy were used to confirm their proposed structures. Moreover, the antibacterial and antifungal activities of certain synthesized compounds, specifically 2,3,6,11,13,15,17, and 18, were assessed against Staphylococcus aureus, Escherichia coli, and Candida albicans, demonstrating encouraging outcomes.Keywords: Antibacterial, antifungal activity, oxadaizole, heterocyclic derivatives, Oxazole. [ABSTRACT FROM AUTHOR]

Conjugation of glycosyl isothiocyanates and steroidal amino alcohol derived from estrone, followed by an oxidative cyclodesulfuration reaction allowed the synthesis of a new class of bioactive molecules. This rapid and versatile protocol represents a useful approach toward the synthesis of a wide variety of novel 2-aminobenzoxazoles. The glycoconjugates (mono- and disaccharides) were successfully obtained in good to excellent yields. The acetyl-protected and deprotected compounds were screened for antiproliferative activity against six human cancer cell lines; a total of eight compounds showed mild to moderate activity. Remarkably, both derivatives bearing a mannose moiety exhibited GI50 values at the low μM range. [ABSTRACT FROM AUTHOR]

This document is a research article that focuses on the total synthesis of ajudazol A, a natural product. The authors, researchers from the University of Bonn, provide detailed information about the experimental procedures and characterization data. The document is technical in nature and provides information relevant to organic chemistry and natural product synthesis. [Extracted from the article]

In this study, we introduced the weak electron-accepting oxazole derivative 4,5-diphenyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)oxazole (TPO) into both anthracene and pyrene moieties of a dual core structure. Ultimately, we developed 2-(4-(6-(anthracen-9-yl)pyren-1-yl)phenyl)-4,5-diphenyloxazole (AP-TPO) as the substitution on the second core, pyrene, and 4,5-diphenyl-2-(4-(10-(pyren-1-yl)anthracen-9-yl)phenyl)oxazole (TPO-AP) as the substitution on the first core, anthracene. Both materials exhibited maximum photoluminescence wavelengths at 433 and 443 nm in solution and emitted deep blue light with high photoluminescence quantum yields of 82% and 88%, respectively. When used as the emitting layer in non-doped devices, TPO-AP outperformed AP-TPO, achieving a current efficiency of 5.49 cd/A and an external quantum efficiency of 4.26% in electroluminescence. These materials introduce a new category of deep blue emitters in the organic light-emitting diodes field, combining characteristics related to the electron transport layer. [ABSTRACT FROM AUTHOR]

A powerful analgesic and anti-inflammatory agent were established by preparing a series of new heterocyclic substituted oxazole analogs. The chemical structures of the entire prepared analogs were confirmed by spectroscopic and elemental analyses. Molecular properties, ADME properties, and drug-likeness scores and toxicities of title compounds were predicted using in silico studies. In addition, title compounds were docked against two proteins namely, 3KK6, and 3LN1 using Auto Dock 4.2. In vitro analgesic and anti-inflammatory activities of prepared analogs were estimated using tail flick method and carrageenan-induced foot paw edema technique, respectively. Additionally, ulcerogenicity of potent analogs was also determined. Most of the prepared analogs showed mild-to-good analgesic and anti-inflammatory with low-to-reasonable ulcer index. Among the tested series, the most potent compound was found to be 1-(3-chlorophenyl)-3-methyl-4-(2-(4-((2-methyl-5-oxooxazol-4(5H)-ylidene) methyl)phenyl) hydrazono)-1H-pyrazol-5(4H)-one (OHPA3). [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a degenerative neurological condition that severely affects the elderly and is clinically recognised by a decrease in cognition and memory. The treatment of this disease has drawn considerable attention and sparked increased interest among the researchers in this field as a result of a number of factors, including an increase in the population of patients over time, a significant decline in patient quality of life, and the high cost of treatment and care. The current work was carried out for the synthesis of benzimidazole-oxazole hybrid derivatives as efficient Alzheimer's inhibitors and as a springboard for investigating novel anti-chemical Alzheimer's prototypes. The inhibition profiles of each synthesised analogue against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes were assessed. All the synthesized benzimidazole-based oxazole analogues displayed a diverse spectrum of inhibitory potentials against targeted AChE and BuChE enzymes when compared to the reference drug donepezil (IC50 = 2.16 ± 0.12 M and 4.50 ± 0.11 µM, respectively). The most active AChE and BuChE analogues were discovered to be analogues 9 and 14, with IC50 values of 0.10 ± 0.050 and 0.20 ± 0.050 µM (against AChE) and 0.20 ± 0.050 and 0.30 ± 0.050 µM (against BuChE), respectively. The nature, number, position, and electron-donating and -withdrawing effects on the phenyl ring were taken into consideration when analysing the structure-activity relationship (SAR). Molecular docking studies were also carried out on the active analogues to find out how amino acids bind to the active sites of the AChE and BuChE enzymes that were being studied. [ABSTRACT FROM AUTHOR]

Chitosan‐functionalized silica‐double magnetite parts that contains magnetite in the core and outer layer of synthetic nanoparticles (Fe3O4@SP@chitosan@Fe3O4) were prepared and approved by field emission scanning electron microscope (FE-SEM), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), X-ray spectroscopy (EDS), transmission electron microscope (TEM), and vibrating sample magnetometry (VSM). The presence of Fe3O4 in the outer shell of the synthetic nanoparticle, in addition to its core, increased the acidity and other properties of the nanoparticle or composite. This structural modification increased the reusability up to eight cycles due to the improvement of magnetic properties, and on the other hands, the reaction time and yields were improved. Fe3O4@SP@chitosan@Fe3O4 nanoparticle supply an eco-friendly procedure for the synthesis of some novel 4-benzylidene-2-phenyloxazol-5-ones through one-pot reaction of various benzoyl chlorides, glycine and synthetized azo-linked benzaldehydes. These high-yield compounds were obtained at short reaction times. The structures of the synthesized 4-benzylidene-2-phenyloxazol-5-ones were confirmed by FT-IR spectroscopy, and 1H and 13C NMR data, and elemental analyses. [ABSTRACT FROM AUTHOR]

Bis(azolylsulfonyl)pyrrole dicarboxamides were prepared from azolylsulfonamides and pyrrole-2,4-dicarboxylic acid under ultrasonication and studied their antimicrobial and cytotoxic activities. Docking methodology was used to predict their binding conformation thereby to explain the biological activities. Chloro substituted bis(oxazolylsulfonyl)pyrrole dicarboxamide (16c), unsubstituted, methyl and chloro substituted bis(imidazolylsulfonyl)pyrrole dicarboxamides (18a, 18b, 18c) showed high affinity toward colchicine binding site and could be used as possible leads for therapies against cancers. All the compounds were screened in vitro for their cytotoxic effect on three cancer cell lines. In fact, 16c, 18a and 18c pretreatment was shown to modulate the cytotoxic activity against lung, colon and prostate cancer cells while 18b against lung and prostate cancer cell lines. Further, antimicrobial studies revealed that unsubstituted, chloro substituted bis(thiazolylsulfonyl)pyrrole dicarboxamides (17a, 17c) and chloro substituted bis(imidazolylsulfonyl)pyrrole dicarboxamide (18c) displayed antibacterial activity against B. subtilis greater than the standard drug Chloramphenicol. Compounds 17c and 18c showed antifungal activity on A. niger greater than the standard drug Ketoconazole. [ABSTRACT FROM AUTHOR]

The coumarins are found in both natural and synthetic compounds that display a broad spectrum of biological properties including anticoagulant, antibacterial, antioxidant, and antiviral as well as anticancer properties. On the other hand, oxazole, thiazole, and imidazole are also important for their antimicrobial, anticancer, antitubercular, anti-inflammatory, antidiabetic, antiobesity properties and act as topoisomerase inhibitors, microtubule polymerization inhibitors and cytochrome P450 enzymes inhibitors. It has been reported that the coumarin fused oxazole, thiazole, and imidazole derivatives were found to exhibit antibacterial, antioxidant, antitumor, anticonvulsant, anti-inflammatory, anticancer as well as antimetastatic activity. The main purpose of this review is to highlight different synthetic methodologies for the synthesis of oxazolo/thiazolo/imidazolocoumarins (either angular or linear) and their biological importances reported in the literature. Several methods for the synthesis of such fused compounds in which 3-nitro/aminocoumarin derivatives are mostly used as the starting material, have been described in the literature. [ABSTRACT FROM AUTHOR]

In an attempt to synthesize new derivatives of imidazo[1,5-a][1,5]benzodiazepine-3-carboxylic acid esters by activation of the amide group of the heterocycle to iminophosphate and its cyclocondensation with ethyl isocyanoacetate, unexpected 5-substituted ethyl oxazole-4-carboxylates were obtained as the main products. Structures of the novel oxazole derivatives were confirmed by IR, 1H, 13C, and 31P NMR, and mass spectra, and the reaction course was rationalized using computational molecular modeling techniques. [ABSTRACT FROM AUTHOR]

Purpose: Ulcer is a serious disease that is caused due to different bacteria and over usage of various NSAIDs which caused to reduce the defensive system of stomach. Therefore, some novel series are needed to overcome these issues. Methods: Oxazole-based imidazopyridine scaffolds (4a-p) were designed and synthesized by two step reaction protocol and then subjected to urease inhibition profile (in vitro). All the newly afforded analogs (4a-p) were found potent and demonstrated moderate to significant inhibition profile. Results: Particularly, the analogs 4i (IC50 = 5.68 ± 1.66 μM), 4o (IC50 = 7.11 ± 1.24 μM), 4 g (IC50 = 9.41 ± 1.19 μM) and 4 h (IC50 = 10.45 ± 2.57 μM) were identified to be more potent than standard thiourea drug (IC50 = 21.37 ± 1.76 μM). Additionally, the variety of spectroscopic tools such as 1H NMR, 13C NMR and HREI-MS analysis were employed to confirm the precise structures of all the newly afforded analogs. Discussion: The structure–activity relationship (SAR) studies showed that analogs possess the substitution either capable of furnishing strong HB like –OH or had strong EW nature such as -CF3 & –NO2 groups displayed superior inhibitory potentials than the standard thiourea drug. A good PLI (protein–ligand interaction) profile was shown by most active analogs when subjected to molecular study against corresponding target with key significant interactions such as pi-pi stacking, pi-pi T shaped and hydrogen bonding.

A series of 4-aryl-2-[2-(arylmethylidene)hydrazinyl]-1,3-oxazoles were synthesized from the corre-sponding aromatic aldehyde semicarbazones and phenacyl bromides. The synthesized compounds were characterized by NMR and high-resolution mass spectra and evaluated for their inhibitory activity against β-glucuronidase. All compounds showed a varying degree of inhibitory potential (IC50) ranging from 2.40±0.10 to 43.20±0.20 µM in comparison with the standard drug D-saccharic acid 1,4-lactone (IC50 = 48.4±1.25 µM). The most potent analogs displayed IC50 values of 2.40±0.10 and 5.30±0.20 µM. A limited structure–activity relationship analysis was performed, which showed that the nature, position, and number of the substituents on phenyl ring are the major factors responsible for the inhibitory activity. A molecular docking study was carried out to determine the binding interaction of the most potent compounds in the active site of the enzyme. [ABSTRACT FROM AUTHOR]

To better understand the molecular definition of 3-[4-(trifluoromethyl)phenyl]-3a,4,8,8a-tetrahydro-6H-[1,3] dioxepino[5,6-d][1,2]oxazole (OXE–OXA) compound, we examined its molecular geometric structure and spectroscopic properties in detail. First, we determined the OXE–OXA compound's crystal structure using single-crystal X-ray diffraction data, then we grew a single crystal of the OXE–OXA compound using the slow evaporation solution magnification technique at room temperature with ethanol. It was found that the OXE–OXA compound crystallizes in the monoclinic crystal system with the noncentrosymmetric space group P1 21/n1. We performed the theoretical calculations for OXE–OXA compound at the B3LYP/6-311++G(d,p) and HSEh1PBE/6-311++G(d,p) levels of the density functional theory method. According to the comparison of our obtained data, the experimental 1H and 13C nuclear magnetic resonance chemical shifts were in strong agreement with the values for simulated chemical shifts. Later, we investigated the experimental FT-IR and theoretical IR spectrum of OXE–OXA compounds in the 4000–400 cm–1 region. [ABSTRACT FROM AUTHOR]

Two series of bis-2,5-diphenyloxazolato cyclometalated iridium(III) complexes with substituted 2,2′-bipyridine or dipyridophenazine as the ancillary ligand have been prepared and characterized by X-ray structural analysis, 1H NMR, and high resolution mass spectrometry. Bipyridine-based complexes exhibited bright emission in the yellow-orange region in solution, whereas their dipyridophenazine analogues demonstrated low quantum yields in the same spectral area. Varying the substituents in the ancillary ligand (CH3, H, COOH) caused noticeable shifts of the long-wavelength absorption bands retaining the redox potentials of the complexes practically unchanged. Crystallization of the complexes with iodine species gave interesting salts containing infinite polyiodide chains forming intermolecular contacts with the π-system of the ligands. Complexes bearing "anchoring" COOH-groups were used in sensitization of titania photoanodes followed by their study under the AM 1.5 G condition. [ABSTRACT FROM AUTHOR]

A new series of dihydro-1, 2-oxazole coumarin derivatives (SR1-SR10) was prepared using a multi-step reaction. The syntheses of intermediates coumarinyl chalcones and final compounds were characterized by IR, Mass, and 1H NMR spectra. The final compound's SR1-SR10 binding mode and its inhibitor susceptibility were studied by molecular docking with the receptor DNA gyrase B (PDB code: 5L3J). It is responsible for catalyzing changes during DNA replication and validated targets for antibacterial molecules. The docking score of compounds SR1-SR10 ranges from -4.18 to -2.15 kcal mol-1. Among all these compounds, chloro-substituted dihydro isoxazole chromen-2-one (SR10) showed the best docking score with -4.18 kcal mol-1. SR10 interacted with the ATP-binding site of E. coli DNA gyrase B through a hydrogen bond with GLY77 and hydrophobic bond, charged negatives and polar interaction. SR1-SR10 antibacterial inhibitory property by tube dilution method was performed, and its minimum inhibitory concentrations (MIC) were observed. The MIC values of (SR1-SR10) range from 3.12 to 25 µg mL-1. Compounds SR3 and SR10 showed significant antibacterial activity with a MIC value of 3.12 µg mL-1. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of 2,4-disubstituted-oxazole derivatives were designed and synthesized from lead 3a. • 5k increased glucose consumption by 60 % in HepG2 cells compared to the solvent control. • An oral glucose tolerance test confirmed that 5k is an effective hypoglycemic agent. • Compound 5k showed weak inhibitory activity against various subtypes of human cytochrome P450. • Compound 5k may exert its hypoglycemic activity through the activation of the AMPK pathway. A series of 2,4-disubstituted-oxazole derivatives have been designed and synthesized based on compound 3a, a promising lead compound developed in our lab. Among these derivatives, the optimized compound 5k exhibited potent hypoglycemic activity, increasing glucose consumption by 60 % in HepG2 cells compared to the solvent control, and its activity was higher than that of metformin. Further investigation indicated that compound 5k exhibited negligible cytotoxic effects at a concentration of 25 μM in HepG2 and 3T3-L1 cells and showed moderate inhibitory activity against various subtypes of human cytochrome P450 subtypes. An oral glucose tolerance test confirmed that 5k is an effective hypoglycemic agent. Additionally, mechanistic studies suggested that 5k may exert its hypoglycemic activity through the activation of the AMPK pathway. [ABSTRACT FROM AUTHOR]

Oxazoles and Imidazoles are heterocyclic compounds with significant biological activities. The present study explores the pharmacological effects of some new oxazole and imidazole derivatives as potential COX-2 inhibitors. Docking studies of the compounds against targeted proteins COX-2 and TACE manifested good binding affinities for both the targets supporting their anti-inflammatory potential. Compounds (3F-A, 3F-B, N-A, N-B) were evaluated for in vivo anti-inflammatory effects by carrageenan-induced paw edema. Among all, compound N-A was found to be the most effective as it displayed most pronounced reduction in inflammation that was comparable to indomethacin. The in vivo tissue antioxidant activity was performed for estimation of the level of catalase, GSH, GST, and thiobarbituric acid in paw tissue. The results exhibited that targeted compounds improved the oxidative stress and restored the expression of enzymes. H &E staining revealed that aforesaid compounds displayed well-defined restoration of cellular damage. Compound NA exhibited maximum structural and functional preservation. Reduction in the expression of inflammatory markers was also analyzed by ELISA and maximum reduction in protein expression (COX-2 and TNF-a) was observed for compound N-B. Quantification of mRNA was done using PCR and a decrease in the expression of COX-2 mRNA level in treatment groups was depicted by all the new compounds but N-B showed maximum reduction in enzyme expression. All the results obtained from the present study have shown the significant anti-inflammatory potential of new compounds via the COX-2 inhibition pathway. [ABSTRACT FROM AUTHOR]

In this study, we introduced the weak electron-accepting oxazole derivative 4,5-diphenyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)oxazole (TPO) into both anthracene and pyrene moieties of a dual core structure. Ultimately, we developed 2-(4-(6-(anthracen-9-yl)pyren-1-yl)phenyl)-4,5-diphenyloxazole (AP-TPO) as the substitution on the second core, pyrene, and 4,5-diphenyl-2-(4-(10-(pyren-1-yl)anthracen-9-yl)phenyl)oxazole (TPO-AP) as the substitution on the first core, anthracene. Both materials exhibited maximum photoluminescence wavelengths at 433 and 443 nm in solution and emitted deep blue light with high photoluminescence quantum yields of 82% and 88%, respectively. When used as the emitting layer in non-doped devices, TPO-AP outperformed AP-TPO, achieving a current efficiency of 5.49 cd/A and an external quantum efficiency of 4.26% in electroluminescence. These materials introduce a new category of deep blue emitters in the organic light-emitting diodes field, combining characteristics related to the electron transport layer.

Alzheimer’s disease (AD) is a degenerative neurological condition that severely affects the elderly and is clinically recognised by a decrease in cognition and memory. The treatment of this disease has drawn considerable attention and sparked increased interest among the researchers in this field as a result of a number of factors, including an increase in the population of patients over time, a significant decline in patient quality of life, and the high cost of treatment and care. The current work was carried out for the synthesis of benzimidazole-oxazole hybrid derivatives as efficient Alzheimer’s inhibitors and as a springboard for investigating novel anti-chemical Alzheimer’s prototypes. The inhibition profiles of each synthesised analogue against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes were assessed. All the synthesized benzimidazole-based oxazole analogues displayed a diverse spectrum of inhibitory potentials against targeted AChE and BuChE enzymes when compared to the reference drug donepezil (IC50 = 2.16 ± 0.12 M and 4.50 ± 0.11 µM, respectively). The most active AChE and BuChE analogues were discovered to be analogues 9 and 14, with IC50 values of 0.10 ± 0.050 and 0.20 ± 0.050 µM (against AChE) and 0.20 ± 0.050 and 0.30 ± 0.050 µM (against BuChE), respectively. The nature, number, position, and electron-donating and -withdrawing effects on the phenyl ring were taken into consideration when analysing the structure-activity relationship (SAR). Molecular docking studies were also carried out on the active analogues to find out how amino acids bind to the active sites of the AChE and BuChE enzymes that were being studied.

Interaction between α-(N-alkylamino) ketones and 1,1,3-trichloro-1H-isoindole in the presence of tertiary amine leads to nucleophilic substitution of three chlorine atoms and formation of 3-amino-1H-isoindol-1-ylidene-1-aminium quaternary salts possessing two amino ketone residues. Both substituents at nitrogen in aminium salts can adopt either (Z)- or (E)-configuration. Their treatment with bases in air leads via blue enolates (λmax 595.5 nm, CHCl3) to a relatively stable free radical, probably of a bisspiro structure. Reaction can also proceed further with isoindole ring opening and formation of (1H-imidazol-2-yl)phenyl-1,3-oxazol-3-ium derivative. Oxazolium moiety undergoes easy hydrolytic ring cleavage leading to 2-(1H-imidazol-3-ium)benzamide derivative. When N,N-dimethylbenzylamine is used as a base, the reaction proceeds via its cleavage and formation of unsymmetrical aminium salt containing both dimethylamino group along with α-(N-alkylamino) ketone residue. [ABSTRACT FROM AUTHOR]

A series of triazole linked tetrahydropyran–oxazole hybrids was synthesized based on a previously reported lead compound with selective antiproliferative activity against human tumour cell lines. The series was prepared to evaluate the impact of LogP and different modifications in the activity, and the new compounds were assayed against A549, HBL‐100, HeLa, SW1573, T‐47D, and WiDr cell lines. Also, the potentiality to be P‐gp substrate was tested. The compounds exhibited good antiproliferative results when compared with the standards cisplatin and 5‐fluorouracil. In silico studies to evaluate pharmacokinetic properties using pkCSM software were also carried out. [ABSTRACT FROM AUTHOR]

Eco-friendly, low-cost and high-yielding synthetic route toward imidazoles and oxazoles has been developed. 1-(4,6-Dimethylpyrimidin-2-yl)-2-(alkylamino)-1,5-dihydro-4H-imidazol-4-one 3a–c have been synthesized via regiospecific reaction of ethyl 2-(N-(4,6-dimethylpyrimidin-2-yl)cyanamide)acetate 1 with primary aliphatic amines in water as green solvent. While, the reaction between 4,6-dimethylpyrimidin-2-yl(2-oxo-2-phenylethyl)cyanamide 2 and primary aliphatic amines using water and/or iso-propanol as green solvents afforded 3-(4,6-dimethylpyrimidin-2-yl)-5-phenyl-1,3-oxazole-2(3H)-imine 6 and 1-(4,6-dimethylpyrimidin-2-yl)-N-alkyl-4-phenyl-1H-imidazol-2-amine 7a–d, respectively. [ABSTRACT FROM AUTHOR]

An efficient procedure has been developed for the synthesis of new heterocyclic compounds from 2-substituted functionalized allyl bromides as precursors to electrophilic and nucleophilic building blocks for 1,3-dicarbonyl compounds. [ABSTRACT FROM AUTHOR]

A variety of azolyl pyrimidinyl acetamides were prepared from azolyl glycinate and 4,6-diaryl/heteroarylpyrimidinyl-2-amines in the presence of DMAP under ultrasonication. Nitrophenyl, pyridinyl and indolyl substituted thiazolyl pyrimidinyl acetamides (9c, 9e, 9f) and imidazolyl pyrimidinyl acetamides (10c, 10e, 10f) showed excellent antibacterial activity against B. subtilis and MBC is 2xMIC. The compounds 9c, 10c and 10e also showed excellent antifungal activity against A. niger and MFC is 2xMIC. [ABSTRACT FROM AUTHOR]

Four series of novel hydrazide/thiazol/oxazol/oxime ester hybrids of chromene derivatives were designed and synthesized to explore natural-product-based fungicide candidates. Preliminary antifungal activity assay results demonstrated that hydrazide-chromene and thiazol-chromene derivatives exhibited excellent and broad-spectrum inhibitory activity against ten phytopathogenic fungi. Among them, six compounds 4b , 4c , 4d , 4e , 4h , and 4l displayed the most remarkable antifungal effects. Notably, compounds 4e and 4l showed comparable protective and curative effects with chlorothalonil against potatoes and cherry tomatoes infected by Fusarium solani and Botrytis cinerea , respectively. Meanwhile, compound 4e also exerted potential protective and curative effects against rice and pepper leaves infected by Pyricularia oryzae and Phytophthora capsici , respectively. Additionally, a preliminary antifungal mechanism study revealed that compound 4e could significantly inhibit the germination of spores and promote increased mycelium permeability and content leakage by disrupting the fungal membrane structure. The in vitro cytotoxicity results indicated that almost all of the hydrazide-chromene derivatives possessed relatively low cytotoxicity. These findings provide the foundation for the application of chromene-based derivatives as novel fungicide candidates.

The N , O -acetal derived from diethyl mesoxalate (DEMO) undergoes elimination of acetic acid upon treatment with a base, leading to the formation of N -acylimine in situ. Lithium acetylide readily attacks the imino group to afford N ,1,1-tricarbonylated propargylamines. When the resulting propargylamine reacts with butyllithium, ring closure occurs between the ethynyl and carbamoyl groups, yielding 2,5-disubstituted oxazole-4-carboxylates. This cyclization also occurs when the propargylamine is heated with ammonium acetate, resulting in double activation., (Copyright © 2024, Iwai et al.)

Human immunodeficiency virus (HIV) especially HIV-1 infection and its progression to acquired immune deficiency syndrome (AIDS) remains a significant global health challenge. The advent of the highly active antiretroviral therapy (HAART) has greatly extended the life expectancy of patients living with HIV, but it has become evident that long-term HAART will not eliminate the HIV reservoir and cure the infection. Moreover, the drug resistance and undesirable side effects hamper efficacious therapy, creating an urgent need to develop novel, more effective and less toxic anti-HIV therapeutics. Imidazole, oxazole and thiazole with two heteroatoms at meta-position of five-membered rings are fascinating structures and constitute an important class of heterocycles in drug discovery. Their derivatives could exert the anti-HIV activity through diverse mechanisms and possess promising antiviral activity against both drug-sensitive and drug-resistant HIV strains. This review summarizes the research progress made regarding the anti-HIV potential of imidazole, oxazole and thiazole hybrids, and the structure–activity relationships (SARs) are also discussed to facilitate further rational design of more effective candidates, covering articles published from 2012 to 2022.

The present study envisaged the development of an efficient protocol of Mn-catalyzed reductive carbonylation of aryl iodides to aryl aldehydes and their corresponding imidazole and oxazole derivatives, by using CO as a carbonyl source, in the presence of hydrosilanes and base [Na2CO3 and NaHCO3 (1:1)] under mild reaction conditions gave a series of aldehydes in good yields. This approach could be extended for further functionalization of aryl aldehydes and to their corresponding benzimidazole and benzoxazole derivatives with high efficiency [ABSTRACT FROM AUTHOR]

A polymorphic transition as a result of grinding was found for 3-[1-(tertbutoxycarbonyl) azetidin-3-yl]-1,2-oxazole-4-carboxylic acid. The thorough study of polymorphic structures before and after crystal structure transformation has revealed some pre-conditions for a polymorphic transition and regularities of changes in molecular and crystal structure. In metastable polymorph 1a, the conformationally flexible molecule adopts a conformation with the higher energy and forms a less preferable linear supramolecular synthon. Additional energy imparted to a crystal structure during the grinding process proved to be enough to overcome low energy barriers for the nitrogen inversion and rotation of the oxazole ring around the sp3-sp2 single bond. As a result, polymorph 1b with a molecule adopting conformation with lower energy and forming a more preferable centrosymmetric supramolecular synthon was obtained. The study of pairwise interaction energies in the two polymorphs has shown that metastable polymorph 1a is organized by molecular building units and has a columnar-layered structure. A centrosymmetric dimer should be recognized as a complex building unit in more stable polymorph 1b, which has a layered structure. [ABSTRACT FROM AUTHOR]

The five membered heteroaromatic oxazole motifs and their scaffolds exhibit significant pharmaceutical and biological applications. Remarkably, the high efficiency in the assembly of structurally diverse oxazole scaffolds via C(sp3)‐H functionalization of benzylamines have attracted synthetic organic chemists. In this review, the different synthetic strategies from benzylamines as a new emerging substrate via C−H/C−N bond functionalization towards oxazole synthesis are discussed in detail. Moreover, it highlights substrate scope along with the reaction mechanism involved during the reaction. [ABSTRACT FROM AUTHOR]

The dynamic growth in green organic synthetic methodologies for diverse heterocyclic scaffolds has substantially contributed to the field of medicinal chemistry over the last few decades. The use of hybrid metal nanocatalysts (NCs) is one such benign strategy for ensuring the advancement of modern synthetic chemistry by adhering to the principles of green chemistry, which call for a sustainable catalytic system that converts reacting species into profitable chemicals at a faster rate and tends to reduce waste generation. The metal nanoparticles (NPs) enhance the exposed surface area of the catalytic active sites, thereby making it easier for reactants and metal NCs to have an effective interaction. Several review articles have been published on the preparation of metal NCs and their uses for various catalytic heterocyclic transformations. This review will summarize different metal NCs for the efficient green synthesis of various O-heterocycles. Furthermore, the review will provide a concise overview of the role of metal NCs in the synthesis of O-heterocycles and will be extremely useful to researchers working on developing novel green and simple synthetic pathways to various O-heterocyclic-derived molecules. [ABSTRACT FROM AUTHOR]

• Hint about inflammation response with different inflammatory targets. • Some reported oxazoles and imidazoles as anti-inflammatory agents with different inflammatory targets. • Side effects of non-selective COX inhibitors and selective COX-2 inhibitors. • Reported oxazoles and imidazoles as COX inhibitors with their biological activity and molecular docking. • Synthetic pathways of some oxazole and imidazole derivatives. NSAIDs are the most famous anti-inflammatory drugs and are mainly classified into two groups, the non-selective NSAIDs that inhibit both COX-1 and COX-2 enzymes with side effects such as gastric ulcers and the selective COX-2 inhibitors with more gastric tolerability. Recently, the researchers are seeking to design COX-2 inhibitors with enhanced safety profile. Imidazole and oxazole containing compounds were previously known for their wide scale of biological activities, additionally, they are the blockade for designing COX-2 inhibitors. This article presents some of the previously reported imidazole and oxazole derivatives as COX inhibitors with their reported docking studies. The imidazole and oxazole derivatives below are classified according to the contained substituents, the introduced biologically active ring such as indole ring to the imidazole and oxazole derivatives and the fused ring with the concerned rings. Therefore, substituted imidazole and oxazole can be considered as an interesting scaffold for synthesis of anti-inflammatory agents exhibiting COX-2 selectivity with an enhanced safety profile. Additionally, the activities of the reported derivatives are illustrated by their docking investigations. At the end of the article, the reported synthetic pathways of some imidazole and oxazole derivatives are briefly introduced to be conversant with these derivatives. [Display omitted] [ABSTRACT FROM AUTHOR]

In the title compound, C33H26N4O4, the two fused five-membered rings and their N-bound aromatic substituents form a pincer-like motif. The relative conformations about the three chiral carbon atoms are established. In the crystal, a combination of C—H...O and C—H...N hydrogen bonds and C—H...π(ring) interactions leads to the formation of layers parallel to the bc plane. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H...H (44.3%), C...H/H...C (29.8%) and O...H/H...O (15.0%) contacts.

[Display omitted] • New oxazole-based tanshinone IIA derivatives (1a-n) were synthesized to evaluate α-glucosidase inhibitory activity. • Eight compounds (1a-d , 1f-g , 1j , and 1m) demonstrated excellent inhibition with IC 50 values ranging from 0.73 ± 0.11 to 9.46 ± 0.57 μM. • The most potent compound 1j was 137-fold more potent than standard inhibitor. • Docking studies were conducted to confirm binding of the active compound with protein. α-Glucosidase is one of the therapeutic approaches for treating type 2 diabetes mellitus. Almost 95 % of diabetes patients worldwide have been diagnosed with type 2 diabetes, resulting in 1.5 million fatalities each year. Newly synthesized oxazole-based tanshinone IIA derivatives (1a - n) were designed and evaluated for their inhibitory activity against α-glucosidase enzyme. Eight compounds (1a-d , 1f-g , 1j , and 1m) demonstrated excellent inhibition with IC 50 values ranging from 0.73 ± 0.11 to 9.46 ± 0.57 μM as compared to tanshinone IIA (IC 50 = 11.39 ± 0.77 μM) and standard acarbose (IC 50 = 100.00 ± 0.95 μM). Among this series, 1j bearing two hydroxyls group over the phenyl ring was identified as the most potent α-glucosidase inhibitor with IC 50 value of 0.73 ± 0.11 μM. Molecular docking simulations were done for the most active compound to identify important binding modes responsible for inhibition activity of α-glucosidase. In addition, the kinetic study was also performed to understand the mode of inhibition. [ABSTRACT FROM AUTHOR]

A potent antibacterial drug was developed by synthesizing a set of new pyrazoles substituted oxazole derivatives using multi-step synthesis. FT-IR, ¹H-NMR, Mass spectroscopy, and bases of microanalyses are employed to confirm the structure of compounds. Molinspiration online tool was used to predict the molecular properties and molecular docking was used to predict the antitubercular potency of the target compounds. 10-Fold serial dilution method, agar streak dilution test, and DPPH radical scavenging methods are utilized to evaluate antitubercular, antibacterial, and radical scavenging properties of test compounds and reference drugs, respectively. Varying degree of antitubercular, antibacterial, and radical scavenging activities (mild to good) was displayed by synthesized oxazole compounds. In general, unsubstituted oxazole derivatives exhibited superior antibacterial potency than substituted analogs. In addition, meta-substituted analogs displayed higher activity than the corresponding para-substituted analogs. Among fifteen tested target compounds, the potent compound of this series was found to be 4-(4-(5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)benzylidene)-2-methyloxazol-5(4H)-one (PBO8). Hence, this analog may be used as a lead molecule to find potent & safer antibacterial agents. [ABSTRACT FROM AUTHOR]

Described in this paper are studies on the preparation of three classes of dimethylpyridinols derived from pyridoxine fused with aminooxazole, aminoimidazole, and aminopyrrole. The key feature of this synthetic strategy is the manipulation of hydroxymethyl moiety of C(5)-position of the pyridoxine starting material along with the installation of an amino group at C(6)-position. Efficient and practical synthesis for the oxazole- and imidazole-fused targets was accomplished, while the instability of the pyrrole-fused one was observed. [ABSTRACT FROM AUTHOR]

A new linear luminophore consisting of five conjugated units of oxazole, phenylene and a central benzothiadiazole fragment, 4,7‐bis[4‐(1,3‐oxazol‐5‐yl)phenyl]‐2,1,3‐benzothiadiazole, has been synthesized and characterized. Needle‐like single‐crystal samples up to 10 mm in length were obtained by physical vapor transport. The crystal structure was determined at 95 K and 293 K using single‐crystal X‐ray diffraction. With decreasing temperature, the space group P21/n does not change, but the unit‐cell volume of the crystal decreases. The presence of intra‐ and intermolecular hydrogen bonds was established. Melting parameters (Tm = 305.5°C, ΔHm = 52.2 kJ mol−1) and the presence of a liquid‐crystalline mesophase (TLC = 336.3°C, ΔHLC = 1.4 kJ mol−1) were determined by differential scanning calorimetry and in situ thermal polarization optical microscopy studies. The presence of linear chains of hydrogen bonds ensures high stability of the crystal structure in a wide temperature range. The luminophore is characterized by a large Stokes shift (5120–5670 cm−1) and a high quantum yield of fluorescence, reaching 96% in solutions (λmax = 517 nm) and 27% in thin crystalline films (λmax = 529 nm). The calculated absorption and emission spectra are in good agreement with the experimental data. Because of the excellent optical properties and high thermal stability, the new linear luminophore has great potential for application in organic photonics and optoelectronic devices. [ABSTRACT FROM AUTHOR]

We report here a Cu‐catalyzed enantioselective intramolecular oxidation of cyclic diaryliodoniums. With readily available cyclic diaryliodoniums as building blocks, diversified axially chiral oxazole 2‐iodobiaryls were produced with excellent yield as well as excellent enantioselectivity. Furthermore, these chiral aryl iodides could be transformed into iodine (III) species in situ, which can be employed as chiral catalysts. [ABSTRACT FROM AUTHOR]

We report the design, synthetic route, and cytotoxicity of a library of 49 newly synthesized tricyclic oxazolo[5,4‐d]pyrimidines. The condensed pyrimidinones were constructed from ethyl 5‐aminooxazole‐4‐carboxylate building blocks. A tricyclic ring system was built using the naturally occurring mackinazolinone alkaloid with a focus on the molecular diversity at position C‐2 of the oxazole ring. Synthesized compounds were evaluated against a panel of human cancer cell lines including MCF‐7 (breast), HeLa (cervical), and A549 (lung) in vitro. The results revealed that substitution of halogen‐related aromatic fragments at position C‐2 of the oxazole ring may serve as promising anticancer drug candidates. [ABSTRACT FROM AUTHOR]

A capture reaction of hexadehydro-Diels–Alder (HDDA) derived benzyne with various substituted oxazoles is reported. With methyl, hydrogen, or phenyl as the substituent at 2-position of oxazole, tetraynes afforded epoxyanthracene derivatives or underwent dicarbonylation on benzene ring. The reaction does not require any catalyst or additive. The mechanism behind the reaction was investigated. The obtained polycyclic product structure has potential application value in optoelectronic materials. The availability of dicarbonylated arene implies the uniqueness of HDDA benzyne reaction compared with traditional benzyne. [ABSTRACT FROM AUTHOR]