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The emergence of multi-drug resistant pathogenic bacteria represents a serious and growing threat to national healthcare systems. Most pressing is an immediate need for the development of novel antibacterial agents to treat Gram-negative multi-drug resistant infections, including the opportunistic, hospital-derived pathogen, Acinetobacter baumannii. Herein we report a naturally occurring 1,2-benzisoxazole with minimum inhibitory concentrations as low as 6.25 μg ml−1 against clinical strains of multi-drug resistant A. baumannii and investigate its possible mechanisms of action. This molecule represents a new chemotype for antibacterial agents against A. baumannii and is easily accessed in two steps via de novo synthesis. In vitro testing of structural analogs suggest that the natural compound may already be optimized for activity against this pathogen. Our results demonstrate that supplementation of 4-hydroxybenzoate in minimal media was able to reverse 1,2-benzisoxazole’s antibacterial effects in A. baumannii. A search of metabolic pathways involving 4-hydroxybenzoate coupled with molecular modeling studies implicates two enzymes, chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyltransferase, as promising leads for the target of 3,6-dihydroxy-1,2-benzisoxazole.

Base-promoted benzannulation of conjugated N-sulfonylhydrazones and 3-formylchromones for the synthesis of diverse biaryl sulfones is described. The approach facilitates new C-C and C-S bond formation via the cascade diazo formation/Michael addition/ring opening/denitrogenative sulfonylation/intramolecular cycloaddition/dehydration and introduces diverse functional groups onto biaryl sulfones. The synthesized compounds are converted to aryl sulfones bearing bioactive benzisoxazole and benzofuran frameworks. Moreover, the synthesized biaryl sulfones possess potent turn-on fluorescence sensing and UV absorbance properties.

Herein, we report spiropyrimidinetriones (SPTs) incorporating N-linked azole substituents on a benzisoxazole scaffold with improved Gram-positive antibacterial activity relative to previously described analogues. SPTs have an unusual spirocyclic architecture and represent a new antibacterial class of bacterial DNA gyrase and topoisomerase IV inhibitors. They are not cross-resistant to fluoroquinolones and other DNA gyrase/topoisomerase IV inhibitors used clinically. The activity of the SPTs was assessed for DNA gyrase inhibition, and the antibacterial activity across Gram-positive and Gram-negative pathogens with N-linked 1,2,4-triazoles substituted on the 5-position provides the most worthwhile profile. Directed nucleophilic and electrophilic chemistry was developed to vary this 5-position with carbon, nitrogen, or oxygen substituents and explore structure-activity relationships including those around a target binding model. Compounds with favorable pharmacokinetic parameters were identified, and two compounds demonstrated cidality in a mouse model of

A series of thirty-six novel 5-(2-(4-(benzo[d]isoxazol-3-yl)piperazin-1-yl)acetyl)indolin-2-one and 5-(2-(4-substitutedpiperazin-1-yl)acetyl)indolin-2-one analogues were synthesized, characterized and screened for their in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain. These compounds exhibited minimum inhibitory concentration between 1.56 and 50 μg/mL. Among these derivatives, compounds 10c, 10d, 10j, 10o and 10v (MIC 6.25 μg/mL) displayed moderate activity, while compounds 10e, 10l, 10q, 10w,10x, 12d, 12e and 12i (MIC 3.12 μg/mL) showed good anti-tubercular activity and compounds 10f, 10k, 10p, 10r, 12f, 12j and 12k (MIC 1.56 μg/mL) exhibited excellent anti-tubercular activity. In addition, MTT assay was accomplished on the active analogues of the series against mouse macrophage (RAW 264.7) cells to evaluate the cytotoxic effect of the newly synthesized compounds and selectivity index of the compounds was determined. Keywords: Benzisoxazole, Oxindole, Piperazine, Mycobacterium tuberculosis, Anti-tubercular agents

Two series of novel 4-aryl-2H-pyrido[1,2-c]pyrimidine (6a–i) and 4-aryl-5,6,7,8-tetrahydropyrido[1,2-c]pyrimidine (7a–i) derivatives were synthesized. The chemical structures of the new compounds were confirmed by 1H and 13C NMR spectroscopy and ESI-HRMS spectrometry. The affinities of all compounds for the 5-HT1A receptor and serotonin transporter protein (SERT) were determined by in vitro radioligand binding assays. The test compounds demonstrated very high binding affinities for the 5-HT1A receptor of all derivatives in the series (6a–i and 7a–i) and generally low binding affinities for the SERT protein, with the exception of compounds 6a and 7g. Extended affinity tests for the receptors D2, 5-HT2A, 5-HT6 and 5-HT7 were conducted with regard to selected compounds (6a, 7g, 6d and 7i). All four compounds demonstrated very high affinities for the D2 and 5-HT2A receptors. Compounds 6a and 7g also had high affinities for 5-HT7, while 6d and 7i held moderate affinities for this receptor. Compounds 6a and 7g were also tested in vivo to identify their functional activity profiles with regard to the 5-HT1A receptor, with 6a demonstrating the activity profile of a presynaptic agonist. Metabolic stability tests were also conducted for 6a and 6d.

Literature reported the insulin is an important for the humans and it is secreted in the pancreas and controls, regulates the glucose level. It also controls the mechanism and growth. On decreasing the amount of insulin can caused diabetes, several cancers and other disease. Therefore, there is a need to find promising candidates can binds with insulin and stabilize them. Organic compounds containing hetero atoms have lots of biological potency in different area, therefore, researchers are designing new biological potent compounds. Further, insilico studies attracted the researchers in last one decade mainly to get the drug in less time with a clear strategy. In the present work, authors have designed two types of conjugates, xanthenes with trizole as well benzisoxazole and study their interaction with the insulin using computational methods. The library of compounds was screened through molecules docking in terms of binding energy between the designed compound and the active site of the receptor. Further, their ADME properties are investigated. CMPD19 showed best binding affinity with the insulin and may be considered as oral drug based on the bioactive scores.

Herein, we have designed various benzisoxazole acetamide derivatives with and without glycine spacer as DPP-IV inhibitors. Compounds 9a–d and 11a–e were synthesized and screened for their in vitro DPP-IV inhibition. Compounds 11a and 11c showed moderate activity for DPP-IV inhibition, whereas other remained inactive at 25–200 µM concentrations. DPP-IV inhibition can be a good strategy for modulating diabetes and cancer; hence, we have screened compounds 9a–d and 11a–e for their anticancer activity using MTT assay against A549 and MCF7 cell lines. Compounds 9a–d without glycine spacer have shown good anticancer activity compared to compounds 11a–e with glycine spacer. Compound 9b has shown moderate activity with IC50 values 4.72 ± 0.72 and 4.39 ± 0.809 µM against A549 and MCF7 cell lines, respectively. Interestingly, compound 9c with cyano group has shown very good anticancer activity with IC50 2.36 ± 0.34 µM against MCF7 cell line as compared to fluorouracil with IC50 45.04 ± 1.02 µM.

The title compound, (4-(6-fluorobenzo[d]isoxazol-3-yl) piperidin-1-yl)(morpholino)methanone was prepared from 3-(piperidin-4-yl)benzo[d]isoxazole and evaluated for antiproliferative activity and structure was characterized using IR, 1H NMR, LC-MS spectra and finally the structure was confirmed by X-ray diffraction studies. The compound crystallizes in the monoclinic crystal system with the space group P21/c. The piperidine ring and the morpholine ring in the title compound adopt a chair conformation with the benzisoxazole ring in the planar conformation within the experimental limits. The molecular structure is stabilized by both inter and intra-molecular hydrogen bonds of the type C—H…O and C—H…N respectively which can account for the stability of the molecule. Further, Hirshfeld surface analysis employing 3D molecular surface contours and 2D fingerprint plots have been used to analyze intermolecular interactions present in the solid state of the crystal.

2,1-Benzisoxazoles, also called anthranils, are one of the two types of aromatic bicyclic heterocycles having a benzene ring fused with an isoxazole, which are particularly recognized as valuable intermediates in organic synthesis. Nevertheless several methods can be found in the literature to prepare 2,1-benzisoxazoles, we herein report a new, efficient, simple, mild, and alternative procedure to prepare 3-substituted-2,1-benzisoxazoles from 5-(2-nitrobenzylidene)barbiturates in moderate to good yields (51–82%). All the novel benzisoxazoles showed spectral data fully consistent with the assigned structures, which were unequivocally confirmed by single crystal X-ray analysis. A possible mechanism of the reaction is proposed. In addition, a screening of the bioactivity of these benzisoxazoles as xanthine oxidase inhibitors, antioxidants, and cytotoxic compounds was performed. The benzisoxazole formed from barbituric acid revealed moderate xanthine oxidase inhibitory effects (IC50 = 22.10 μM).

The Kemp elimination reaction is a well-known chemical reaction that is facilitated on a protein surface microenvironment, and in particular is highly accelerated in a unique binding pocket of serum albumin. We have designed and synthesized a fluorescently activatable coumarin derivative with a benzisoxazole scaffold to enable monitoring of the Kemp elimination reaction in terms of fluorescence change for the first time. We show that this fluorescent sensor can sensitively and selectively quantitate serum albumin in blood samples. It also works in a dry-chemistry format.

A new class of phosphoramidate derivatives of 6-fluoro-3-(piperidin-4-yl)benzo[d]isoxazole were synthesized in good to excellent yields (78–96%) by an in situ, three-step process. All the synthesized molecules were evaluated for anti-bacterial and anti-fungal activities using in vitro and in silico methods. The results revealed that the compounds 4b, 4d, 4h, 4i, and 4j exhibited the most promising anti-bacterial activity against S. aureus, B. subtilis, K. pneumoniae, S. typhi and P. mirabilis and anti-fungal activity against A. niger and A. flavus when compared with the standard drugs Norfloxacin and Nystatin at concentrations of 25, 50, 75 and 100 µg/mL. The rest of the title compounds have shown moderate activity against all the bacterial and fungal strains. Molecular docking studies revealed that the synthesized compounds have exhibited significant binding modes with high dock scores ranging from −7.2 to −9.5 against 3V2B protein when compared with the standard drugs Norfloxacin (−5.8) and Nystatin (−6.6) respectively. Hence, it is suggested that the synthesized phosphoramidate derivatives of 6-fluoro-3-(piperidin-4-yl)benzo[d]isoxazole will stand as the promising antimicrobial drug candidates in future.

Demonstrated herein is an AuI -catalyzed annulation of sulfonyl-protected ynamides with substituted 1,2-benzisoxazoles for the synthesis of E-benzo[e][1,3]oxazine derivatives. The transformation involves the addition of benzisoxazole to the gold-activated ynamide, ring expansion of the benzisoxazole fragment to provide an α-imino vinylic gold intermediate, and 1,2-migration of the sulfonamide motif to the masked carbene center to deliver the respective ring-expanded benzo[e][1,3]oxazine of predominant E configuration. A trapping experiment justifies the participation of the α-imino masked gold carbene. DFT computations also support the hypothesized mechanism and rationalize the product stereoselectivity.

The synthesis of a new small library of molecules containing bis-urea/thiourea pendants in lysine conjugated to three different heterocycles is described. The heterocycles used in this study have benzisoxazole/piperazine/piperidine units. After a detailed antimicrobial, antioxidant, and anti-inflammatory evaluation, it was found that the most active compounds are 10, 11, 14, 15, 18, 19 and 10, 11, 19 and 8, 9, 12, 13, 16, 17, respectively. Further, it was observed that the presence of all three entities, that is, urea/thiourea, the substituent (OMe/F), as well as the heterocycle, is highly essential for exerting potent activity. Among the heterocycles, the presence of isoxazole seems to be highly beneficial for exerting good potency. In continuation, docking studies have revealed extraordinary binding efficiency for some of the active compounds. Given their potent biological results and docking score, some of the title compounds could be potential drug candidates for microbial-related diseases and provide a basis for future research into the development of molecules possessing multitask ability.

A method for the catalyst-free synthesis of pyrroloquinolinediones and quinolinedicarboxylates is developed through a one-pot synthesis involving denitrogenation of azide, benzisoxazole formation, aza-Diels–Alder cycloaddition, and dehydrative aromatization. Only stoichiometric amounts of N2 and H2O are produced as by-products. A comprehensive green chemistry metrics analysis indicated that this method is much more efficient and greener than two reported methods for the synthesis of pyrroloquinolinediones.

Several pharmacophore models have been proposed for 5-HT2A serotonin receptor antagonists. These typically consist of two aromatic/hydrophobic moieties separated by a given distance from each other, and from a basic amine. Although specified distances might vary, the models are relatively similar in their general construction. Because our preliminary data indicated that two aromatic (hydrophobic) moieties might not be required for such action, we deconstructed the serotonin-dopamine antipsychotic agent risperidone (1) into four smaller structural fragments that were thoroughly examined in 5-HT2A receptor binding and functional (i.e., two-electrode voltage clamp (TEVC) and intracellular calcium release) assays. It was apparent that truncated risperidone analogues behaved as antagonists. In particular, 6-fluoro-3-(1-methylpiperidin-4-yl)benzisoxazole (4) displayed high affinity for 5-HT2A receptors (Ki of ca. 12 nM) relative to risperidone (Ki of ca. 5 nM) and behaved as a potent 5-HT2A serotonin receptor antagonist. These results suggest that multiple aromatic (hydrophobic) moieties are not essential for high-affinity 5-HT2A receptor binding and antagonist activity and that current pharmacophore models for such agents are very much in need of revision.

BACKGROUND Privileged structures are potentially able to bind to a diverse range of biologically important proteins with high affinities, thus benefiting the discovery of novel bioactive compounds. 1,2-Benxisoxazole derivatives can be such important types of "privileged structures" possessing a rich diversity of biological properties especially in the area of CNS disorders. METHODS This review seeks to explore the most significant examples of 1,2-benzisoxazoles as privileged structures in terms of polypharmacology at the molecular level, specifically focusing on four 1,2-benzisoxazoles (zonisamide, risperidone, paliperidone, and iloperidone) which have been in clinical use and established as effective therapeutics. Furthermore, an updated and detailed account of the pharmacological properties of 1,2-benzisoxazole derivatives as therapeutics for CNS disorders is described. And finally, outlooks on current issues and future directions in this field are also provided. RESULTS 1,2-Benzisoxazole was successfully employed in the discovery and development of zonisamide for the treatment of epilepsy and Parkinson's disease. 1,2- Benzisoxazole is also a significantly important structure for the development of atypical antipsychotics. CONCLUSION It is very reasonable to say that 1,2-benzisoxazole is a good example of a privileged structure because it forms the centerpiece of small molecule chemical entities with a wide range of pharmacological properties, especially in the area of CNS disorders.

The base-mediated photochemical cyclization of 2-azidobenzoic acids with the formation of 2,1-benzisoxazole-3(1H)-ones is reported. The optimization and scope of this cyclization reaction is discussed. It is shown that an essential step of the ring closure of 2-azidobenzoic acids is the formation and photolysis of 2-azidobenzoate anions.

The Pd-catalyzed direct arylation of 2,1-benzisoxazole with aryl bromides to access 3-arylbenzoisoxazoles proceeds in moderate-to-high yields with 1 mol % Pd(OAc)2 or 2 mol % PdCl(C3H5)(dppb) (dppb=1,4-bis(diphenylphosphino)butane) as the catalysts and KOAc as an inexpensive base. A wide variety of (hetero)aryl bromides have been employed successfully. Moreover, arylations followed by benzisoxazole ring opening allowed the preparation of 2-aminobenzophenones in only two steps.

The hollow cavities of coordination cages can provide an environment for enzyme-like catalytic reactions of small-molecule guests. Here, we report a new example (catalysis of the Kemp elimination reaction of benzisoxazole with hydroxide to form 2-cyanophenolate) in the cavity of a water-soluble M8L12 coordination cage, with two features of particular interest. First, the rate enhancement is among the largest observed to date: at pD 8.5, the value of kcat/kuncat is 2 × 10(5), due to the accumulation of a high concentration of partially desolvated hydroxide ions around the bound guest arising from ion-pairing with the 16+ cage. Second, the catalysis is based on two orthogonal interactions: (1) hydrophobic binding of benzisoxazole in the cavity and (2) polar binding of hydroxide ions to sites on the cage surface, both of which were established by competition experiments.

White spot syndrome virus (WSSV), an aquatic virus infecting shrimps and other crustaceans, is widely distributed in Asian subcontinents including India. The infection has led to a serious economic loss in shrimp farming. The WSSV genome is approximately 300 kb and codes for several proteins mediating the infection. The envelope proteins VP26 and VP28 play a major role in infection process and also in the interaction with the host cells. A comprehensive study on the viral proteins leading to the development of safe and potent antiviral therapeutic is of adverse need. The novel synthesized compound 3-(1-chloropiperidin-4-yl)-6-fluoro benzisoxazole 2 is proved to have potent antiviral activity against WSSV. The compound antiviral activity is validated in freshwater crabs (Paratelphusa hydrodomous). An in silico molecular docking and simulation analysis of the envelope proteins VP26 and VP28 with the ligand 3-(1-chloropiperidin-4-yl)-6-fluoro benzisoxazole 2 are carried out. The docking analysis reveals that the polar amino acids in the pore region of the envelope proteins were involved in the ligand binding. The influence of the ligand binding on the proteins is validated by the molecular dynamics and simulation study. These in silico approaches together demonstrate the ligand's efficiency in preventing the trimers from exhibiting their physiological function.

Background:Triple Negative Breast Cancer (TNBC) tends to be more aggressive than other types of breast cancer. Resistance to chemotherapy is a major obstacle hence there is a significant need for new antineoplastic drugs with multi-target potency. Numerous Benzoisoxazole moieties have been found to possess a broad spectrum of pharmacological activities. In the present study, we have synthesized 9 novel derivatives of Benzisoxazole 7(a-i) and screened them for their biological potential.Methods:Chemical synthesis, Mass spectrometry (HRMS), cell proliferation and cytotoxicity assay, wound healing assay, flow cytometry and nuclear staining. Angio-inhibitory activity assessed by corneal micropocket assay and in vivo peritoneal angiogenesis assay.Results:The Benzisoxazole derivatives 7(a-i) were synthesized and screened for their biological potency by both in vitro and in vivo experimental models. Among the series, compound 3-(1-((3-(3(Benzyloxy)-4-methoxyphenyl)- 4,5-dihydroisoxazole-5-yl)methyl)piperidine-4-yl)6-fluorobenzo[d] isoxazole (7e) was found to be most promising, with an average IC50 value of 50.36 ± 1.7 µM in MTT assay and showed 81.3% cell death. The compound 7e also showed 60-70% inhibition on a recombinant Metastasis-Associated protein (MTA1) induced proliferation and cell migration in MDAMB-231 cells, which is known to play a major role in angiogenesis. The anti-tumour studies inferred the regression of tumour activity. This was due to inhibition of neovascularization and evoking apoptosis process as assessed by corneal vascularization, peritoneal angiogenesis and apoptotic hallmarks in 7e treated cells.Conclusion:These findings not only show the biological efficacy of compound 7e but it is also an effective beginning to explore the mechanism of metastasis and cancer therapy strategy targeting MTA1. The observed biological activity makes compound 7e an attractive drug candidate.

The Kemp elimination (reaction of benzisoxazole with base to give 2-cyanophenolate) is catalyzed in the cavity of a cubic M8L12 coordination cage because of a combination of (i) benzisoxazole binding in the cage cavity driven by the hydrophobic effect, and (ii) accumulation of hydroxide ions around the 16+ cage surface driven by ion-pairing. Here we show how reaction of the cavity-bound guest is modified by the presence of other anions which can also accumulate around the cage surface and displace hydroxide, inhibiting catalysis of the cage-based reaction. Addition of chloride or fluoride inhibits the reaction with hydroxide to the extent that a new autocatalytic pathway becomes apparent, resulting in a sigmoidal reaction profile. In this pathway the product 2-cyanophenolate itself accumulates around the cationic cage surface, acting as the base for the next reaction cycle. The affinity of different anions for the cage surface is therefore 2-cyanophenolate (generating autocatalysis) > chloride > fluoride (which both inhibit the reaction with hydroxide but cannot deprotonate the benzisoxazole guest) > hydroxide (default reaction pathway). The presence of this autocatalytic pathway demonstrates that a reaction of a cavity-bound guest can be induced with different anions around the cage surface in a controllable way; this was confirmed by adding different phenolates to the reaction, which accelerate the Kemp elimination to different extents depending on their basicity. This represents a significant step toward the goal of using the cage as a catalyst for bimolecular reactions between a cavity-bound guest and anions accumulated around the surface.\ud \ud

A new series of spiro-quinoline compounds have been accomplished by the reaction of barbituric acid or thiobarbituric acid with derivatives of benzisoxazole-5-carbaldehyde or 2-substituted benzaldehyde. These compounds were evaluated for their in vitro cytotoxicity on two mammalian cancer cell lines MCF-7 and KB. The compounds exhibit cytotoxicity against these cell lines in micromolar range. Among the series of compounds, 11(a–j) particularly 11b and 11e showed relatively good activity against both the tested cell lines. Compound 11b was found to exhibit the highest cytotoxic activity with IC50 value 90.2 µM for MCF-7 and 49.8 µM for KB cell line. Flow cytometric analysis study confirmed that these molecules induced cytotoxicity via apoptosis.

Synthesis of some new fluoren-9-ones and benzisoxazoles under both thermal and microwave conditions is reported. The prepared products under microwave conditions are obtained with high yields and within shorter reaction times. Reaction of lithiated bromobenzene with aromatic aldehydes 2a,b delivered diarylmethanols 3a,b that were oxidized to 4a,b. Compound 4a was cyclized to give methoxyfluoren-9-one 5, which was demethylated affording hydroxyfluoren-9-one 6. Compound 4b was reacted with triethyl phosphite to produce benzisoxazole 10. On the other hand, reaction of triethyl phosphite with 13a,b afforded a mixture of phosphoramidates 14a,b and benzisoxazoles 15a,b. The structures of the synthesized compounds have been elucidated unambiguously by NMR-spectroscopic methods including HH COSY, HSQC, and HMBC experiments.