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The Ph3P-I2-mediated reactions between isatins and amines were extensively investigated leading to the discovery of highly selective and divergent routes toward the synthesis of two distinct classes of indole-based frameworks. Through a strategic design of the reaction paths, we overcome potential side reactions to achieve convenient and straightforward one-pot methods to access either indoloquinazolines with C-12 carboxamide or 2-aminosubstituted indol-3-ones using the same reagent system. Mechanistic studies reveal the role of Ph3P-I2 in governing product selectivity, providing an efficient route to novel fused-indolone derivatives with promising applications in drug discovery and medicinal chemistry., (© 2025 Wiley‐VCH GmbH.)

Ph 3 P-I 2 -mediated condensation reactions of isatoic anhydrides and o -phenylenediamines have been developed for the regioselective syntheses of a wide range of linearly and angularly fused benzoimidazoquinazolinones. The selectivity of the products relies on the generation of either highly electrophilic oxyphosphonium or less reactive imidate intermediates. A direct amine attack at the C-2 position of the oxyphosphonium intermediate presumably drives the reaction toward the linearly fused products, whereas an attack of the diamine at the C-4 position of the in situ generated cyclic imidate leads to the angularly fused derivatives. This strategy serves as a practical handle for the efficient synthesis of other related heterocycles.

Fluoroquinolones (FQs) are among the antibiotics whose widespread use in farm-raised animals results in potentially harmful residues in the end products. Additionally, most Thai farmers use antibiotics. Amoxicillin and enrofloxacin were commonly used by pig farms, and hens were given enrofloxacin to prevent immunization side effects. Moreover, antibiotic overuse has harmed food safety in the long term, and the use of low-dose antibiotics causes bacterial resistance. Herein, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was used to make a fast, easy, sensitive, and cost-effective method for monitoring FQs residues. After immunizing hens with mixed multi-hapten ciprofloxacin-bovine serum albumin (CPFX-BSA) with norfloxacin-bovine serum albumin (NFX-BSA), the IgY antibody purified from egg yolk was used for the detection of FQs residues in chicken and pork samples. The efficiency of the IgY antibody showed excellent sensitivity, with 50% inhibitory concentration (IC 50 ) of enrofloxacin at 0.05 µg/mL, far below the MRLs defined by the EU for muscle samples, which was not to exceed 100 µg/kg. The recovery range for chicken muscle samples spiked with ENFX concentrations of 1.00-0.01 µg/mL was 86.65-112.71%, similar to pork samples, which were 84.24-117.22.2%. This method has a lot of potential for analyzing fluoroquinolones in complex samples quickly, easily, and at a low cost on-site. The IgY-based ic ELISA was developed to detect ciprofloxacin (CPFX), norfloxacin (NFX), and enrofloxacin (ENFX) residues; it confirms that IgY could be a promising choice for the detection of antibiotic residues in food samples.

Amyloid beta peptides (A β 1-42) have been found to be associated with the cause of Alzheimer's disease (AD) and dementia. Currently, methods for detecting A β 1-42 are complicated and expensive. The present study is aimed at developing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect A β 1-42 by using a polyclonal antibody from alpaca, an application used in urine samples. The serum was collected from the alpaca after immunizing it with A β 1-42 at 500  μ g/injection 5 times. The ic-ELISA was developed and showed a half-maximal inhibitory concentration (IC 50 ) of 103.20 ng/ml. The limit of detection (LOD) was 0.39 ng/100  μ l. The cross-reactivity was tested with A β 1-40 and 8 synthesized peptides that had sequence similarities to parts of A β 1-42. The cross-reactivity of A β 1-40 and peptide 1 (DAEFRHDSGYE) was 55% and 69.4%, respectively. The ic-ELISA was applied to analyze A β 1-42 in the urine and precipitated protein urine samples. This method can be used for detecting a normal level of total soluble A β (approximately 1 ng in 5 mg of precipitated urine protein) and can be used for detecting the early stages of AD. It is considered to be an easy and inexpensive method for monitoring and diagnosing AD., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Anurak Wongta et al.)

A novel phosphonium-mediated reaction of isatins is described. In the presence of alcohol, the reaction proceeds to furnish C-12 modified tryptanthrin derivatives. Without alcohol, self-dimerization of isatins gives rise to tryptanthrin and its analogs. This divergent and step-economic approach provides a facile access to diverse indoloquinazoline structures including the natural alkaloids, methylisatoid and cephalanthrin B, in high yields from simple precursors under mild and metal-free reaction conditions.

An atom- and step-economic synthesis of aryliminophosphoranes bearing ortho urea was achieved via unprecedented Ph 3 P-I 2 mediated ring-opening of 1,3-dihydro-1 H -benzimidazol-2-ones with secondary amines. Tandem aza-Wittig/heterocyclization of the functionalized aryliminophosphoranes upon treatment with isothiocyanates enables a facile access to a single regioisomer of N 1 -substituted 2-aminobenzimidazoles as well as fused tetracyclic quinazolinone derivatives in one-pot. 31 P{ 1 H} NMR studies suggested that the urea C-N bond of benzimidazolone is weakened by N -phosphorylation, leading to aminolysis rather than the expected deoxygenative amination.

Instead of the expected substituted 2-aminobenzo[ d ]oxazoles, relatively stable ring-opened oxyphosphonium betaines were isolated for the first time from the Ph 3 P-I 2 -mediated reactions of benzo[ d ]oxazol-2(3 H )-ones with acyclic secondary amines. The structure of one of these compounds was unambiguously confirmed by single-crystal X-ray analysis. Thermolysis of the betaines gave rise to 2-dialkylaminobenzoxazoles with concomitant loss of triphenylphosphine oxide, suggesting their possible role as intermediates in an alternative reaction path.

A highly diastereoselective synthesis of anti-α-allyl-β-fluoroamines has been developed involving enantioselective α-fluorination of aldehydes followed by a diastereoselective Petasis allyl borono-Mannich reaction. The products are obtained generally in good overall yields for the two steps and with drs of 97 : 3-99 : 1 and ees of 86-92%. Selected products were converted to 3-, 5- and 6-membered ring heterocycles, the latter two types incorporating an exo-cyclic fluorine.

The unprecedented reaction of tertiary amines with 2(3 H)-benzoxazolones has been investigated. In the presence of the Ph 3 P-I 2 reagent system, the reaction of both acyclic and cyclic aliphatic tertiary amines led to the formation of 2- N, N-dialkylaminobenzoxazoles with the selective cleavage of an alkyl group. Especially, N-(2-iodoethyl)piperazinyl derivatives were rapidly produced in good yields when using DABCO as the nitrogen source. Only in the cases when the nucleophilicity of the substrates exceeds that of the amine, competitive self-condensation of benzoxazolones then proceeds preferentially. 31 P{ 1 H}-NMR study suggested the involvement of an aryloxyphosphonium intermediate and/or possibly 2-iodobenzoxazole which activates the C-2 position of benzoxazolones toward nucleophilic aromatic substitution.

The first direct one-pot approach for the synthesis of N -substituted amidoximes from secondary amides or the intermediate amides has been developed. Through the Ph 3 P-I 2 -mediated dehydrative condensation, a variety of N -aryl and N -alkyl amidoximes (R 1 (C[double bond, length as m-dash]NOH)NHR 2 , where R 1 or R 2 = aryl, alkyl, or benzyl) were readily afforded under mild conditions and short reaction times. The synthetic application of the obtained amidoximes has also been demonstrated through the formation of 1,2,4-oxadiazolones via base-mediated carbonylative cyclization with 1,1'-carbonyldiimidazole., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A convenient one-pot procedure for the synthesis of acyclic and cyclic guanidines mediated by the Ph 3 P/I 2 system is described. Sequential condensation of aryl isothiocyanates with amines followed by dehydrosulfurization and guanylation could lead to both symmetric and unsymmetric N,N',N″-substituted derivatives. Through a tandem guanylation-cyclization, a series of 2-iminoimidazolin-4-ones could also be prepared in good yields from the reaction of aryl isothiocyanates with amino acid methyl esters.

5-Substituted-2-ethoxy-1,3,4-oxadiazoles were conveniently prepared through a one-pot sequential N-acylation/dehydrative cyclization between ethyl carbazate and N-acylbenzotriazoles in the presence of Ph 3 P-I 2 as a dehydrating agent. Subsequent treatment with a stoichiometric amount of alkyl halides (X = Cl, Br, I) enables a rapid access to a variety of 3,5-disubstituted 1,3,4-oxadiazol-2(3H)-ones in good to excellent yields.

Readily available N-substituted amides or their requisite carboxylic acids or acid chlorides have been used to construct 2,3-disubstituted-3H-quinazolin-4-ones in a one-pot procedure. Key transformation in this convergent approach involves Ph 3 P-I 2 -mediated formation of amidine upon condensation of an amide or the intermediate amide with methyl anthranilate. Cyclization of the amidine-tethered anthranilate then affords 2,3-disubstituted-3H-quinazolin-4-ones in good to excellent yields under mild conditions.

An ultrasound-assisted one-pot acylation/cyclization reaction between N-acylbenzotriazoles and 2-hydroxybenzaldehydes has been developed for the synthesis of substituted 3-arylcoumarins. Using ultrasound not only allows rapid and clean conversion but also simplifies experimental setup and parallel workup leading to rapid generation of 3-arylcoumarin libraries under mild, solvent-free, and chromatography-free conditions.

1,1-Dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) is the major metabolite of insecticide 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT) and a persistent organic pollutant (POPs) with concerns regarding its bioaccumulation and persistence in the environment and food chain. In the present study, an indirect competitive enzyme-linked immunosorbant assay (ic-ELISA) specific for the detection of p,p'-DDE is described. In hapten synthesis, 2,2'-bis(4-chlorophenyl)ethanol and glutaric anhydride were used as precursor and spacer arm, respectively. The hapten was then conjugated to bovine serum albumin (BSA) as immunogen for mouse immunization and also conjugated to ovalbumin as coating antigen for ELISA. The developed ic-ELISA was used for detecting p,p'-DDE in human milk samples and validated against the results from conventional gas chromatography-electron capture detection (GC-ECD). Coefficients of variation (%CV) of ELISA were 5.7-10.4% for intra-assay and 10.6-19.6% for interassay variations. The Pearson correlation coefficient of p,p'-DDE concentrations between ic-ELISA and GC-ECD was r = 0.766, which was in an acceptable range. The results indicate that the developed assay could be an alternative analytical tool for monitoring p,p'-DDE in lipimic matrices such as human milk.

In Thailand detection of acaricide dicofol residues has been sporadically performed due to the limitation of analytical techniques. Conventional analytical methods for detecting dicofol residues most often use chromatographic-based techniques. Our ultimate aim is to develop an alternative method for rapidly analyzing dicofol residues in vegetables and fruit samples. Here we report the production of monoclonal antibodies specific to dicofol and its derivatives. Hapten-protein carriers were prepared by linking succinic anhydride to dichlorobenzhydrol (DCBH), which was then conjugated to bovine serum albumin (BSA) and oval albumin (OVA). DCBH-BSA conjugate was used as immunogen while DCBH-OVA conjugate was used as capture antigen for competitive inhibition assay. Female BALB/c mice were immunized with DCBH-BSA conjugate subcutaneously, and antibody (Ab) level was determined 2 weeks after the last immunization. Spleen cells producing high titer antibody were isolated and fused with myeloma cells of P3.X6.Ag8.653. After limiting dilutions, antibody produced by one clone had high affinity, which was found to be of IgG1 with κ light chain. Specificity and inhibition concentrations of the monoclonal antibody (MAb) were determined by competitive indirect ELISA with dicofol, and its 50% (IC(50)) was 0.28 μg/mL. Working ranges of the developed immunoassay were from 0.07 to 25 μg/mL. Hence, the prepared MAb will be able to be applied for immunoassay development for detecting dicofol residue in vegetables and fruits far below the maximum residue limit such that 5 g of fruits and berries can be detected below 0.1 mg/kg.

Neurotrophins are a family of growth factors that regulate the peripheral and central nervous system. We designed and tested a mini-library of small molecules peptidomimetics based on beta-turns of the neurotrophin growth factor polypeptides NT-3, which is the natural ligand for TrkC receptors. Biological studies identified a peptidomimetic 2Cl that exhibited selective antagonism of TrkC. 2Cl reduces TrkC activation and signaling promoted by NT-3, and selectively blocks ligand-dependent cell survival. 2Cl also blocks ligand-independent TrkC activation and signals that take place when the receptor is over-expressed. This work adds to our understanding of how the neurotrophins function through Trk receptors, and demonstrates that peptidomimetics can be designed to selectively disturb neurotrophin-receptor interactions, and receptor activation.

Salbutamol, one of the beta-agonists, is misused as a growth promoter in meat producing animals. In-house synthesized colloidal gold was conjugated with the polyclonal anti-salbutamol antibodies. A rapid immunochromatographic assay was developed in a competitive format. The salbutamol-BSA conjugate and goat anti-rabbit IgG were immobilized on a nitrocellulose membrane as test and control lines, respectively. The color intensity of a purple test line was inversely proportional to the amount of salbutamol presenting in the samples. The sensitivity was estimated to be about 80 ng/mL of salbutamol in PBS. The method can be useful as an "on-site" screening procedure for detection of salbutamol.

We report a novel one-step immunochromatographic strip test for the rapid, qualitative detection of nevirapine in plasma samples from human immunodeficiency virus-infected patients. The sensitivity was 100% (95% confidence interval [95% CI], 97.8 to 100%), and the specificity was 99.5% (95% CI, 97.2 to 99.9%). The limit of detection was 25 ng/ml. Immunochromatographic strip tests are simple, rapid, and cheap assays that could greatly facilitate drug level monitoring in resource-limited settings.

We designed a minilibrary of 55 small molecule peptidomimetics based on beta-turns of the neurotrophin growth factor polypeptides neurotrophin-3 (NT-3) and nerve growth factor (NGF). Direct binding, binding competition, and biological screens identified agonistic ligands of the ectodomain of the neurotrophin receptors TrkC and TrkA. Agonism is intrinsic to the peptidomimetic ligand (in the absence of neurotrophins), and/or can also be detected as potentiation of neurotrophin action. Remarkably, some peptidomimetics afford both neurotrophic activities of cell survival and neuronal differentiation, while others afford discrete signals leading to either survival or differentiation. The high rate of hits identified suggests that focused minilibraries may be desirable for developing bioactive ligands of cell surface receptors. Small, selective, proteolytically stable ligands with defined biological activity may have therapeutic potential.

A program to identify small molecules that mimic or disrupt protein-protein interactions led us to design the peptidomimetics 1-3. Solid-phase syntheses of 1-3 were developed. The purities of the crude materials isolated from the resin tend to be highest for the S- and N-compounds 2 and 3 and better than in the corresponding syntheses of peptidomimetics A. The particular dipeptide units incorporated were chosen to correspond with the turn regions of the neurotrophins (e.g., nerve growth factor [NGF] and the neurotrophin factor-3 [NT-3]). Preliminary studies were performed to access the binding of these analogues to Trk receptors and their ability to induce cell survival (just as NGF and NT-3 do). Several active compounds were identified. However, poor water solubilities of some of the other compounds preclude reliable testing. Consequently, solid-phase modifications to the synthetic procedures were investigated to provide access to the derivatives 12-14 in which the aromatic nitro group is replaced by amine, guanidine, or sulfonamide functionalities. The latter are more acceptable pharmacophores than nitro groups and also tend to increase the water solubilities of the peptidomimetics.

Methodology is presented for assembling fluorescently labeled bivalent molecules from monovalent constituents, without side chain protection or coupling agents. To illustrate the procedure, a series of bivalent peptidomimetics directed toward the Trk receptors were prepared and screened via fluorescent activated cell sorting scan assays.

Efficient solid phase syntheses of the constrained beta-turn peptidomimetics 1-3 were devised, and the conformational properties of three representative compounds in DMSO were determined.

beta-Turn peptidomimetics 1 were designed to mimic hot spots of neurotrophin-3 (NT-3) and others. Solid-phase syntheses of these were developed, though limitations were encountered with scale-up. Consequently, an alternative design with 2 was investigated. 1 and 2 favored distorted type I beta-turn conformations in solution. It was found that peptidomimetic 2b has NT-3-like neurotrophic activity in cell survival assays, selectively binds the NT-3 receptor TrkC, and induces the tyrosine phosphorylation of the TrkC receptor.

Bifunctional linker-scaffolds (compounds 1-3) were designed to meet several criteria for solid-phase syntheses of bivalent ligands. They have two amine-functionalized arms that can be differentially protected. Elaboration of these arms could give ligand-pharmacophore dimers wherein the two active components are held reasonably rigidly at around 10 A separation. Their bifunctional design also enables reactions of libraries with libraries to amplify diversity in a truly combinatorial fashion. Molecules 1-3 are also designed so that cleavage of the linker liberates the scaffold entity into solution under conditions that create only byproducts that should not interfere with biological assays. Thus they contain 2-nitrobenzene sulfonamide components that cleave in the presence of good nucleophiles. In the event, the linker-scaffolds 1-3 were prepared (Schemes 1 and 2). The N-benzyl system 2 was shown to have good stability to the types of conditions that might be used to functionalize the scaffold arms and to be sufficiently labile to the cleavage nucleophile (vide infra). The nucleophiles generally used to cleave nitrobenzene sulfonamides either generate undesirable byproducts (thiophenol or alkane thiols) or proved to be insufficiently reactive for the required solid-phase transformations (n-propylamine). However, sodium sulfide was investigated as a new alternative and shown to be a highly reactive cleavage agent that gives only volatile byproducts and sodium hydroxide. It is suggested that sodium sulfide is a highly desirable nucleophile for cleavage of 2-nitrobenzene sulfonamides, in general. The linker-scaffolds 1-3 were used to prepare a small library of bivalent ligands targeted to a protein receptor having charged cavities separated by approximately 10 A. These systems were made from guanidine, pyridinium, carboxylic acid, and sulfonic acid constituents (Tables 1 and 2).

A library of guanidine-based compounds was produced to mimic the lead compound 1, which is a substance known to have intensely sweet-taste characteristics. Libraries of guanidinocarboxylic acids were therefore prepared via two synthetic methods. The solid-phase method involving trapping of solution-phase carbodiimides by supported amines was used to produce N,N'-dialkyl derivatives (Scheme 1). The second solid-phase method, featuring supported carbodiimides and solution-phase amines (Scheme 2), was devised to prepare N,N'-disubstituted and N,N',N'-trisubstituted guanidinocarboxylic acids. A small collection of guanadinoacetic acid dimers and trimers was also prepared, but this time via a solution-phase coupling of carbodiimides to a polyamine linker.

[formula: see text] Efficient solid-phase SN2 macrocyclization reactions were sought to facilitate preparations of focused libraries of beta-turn mimetics. A very efficient, but undesired, cyclization reaction to give five-membered ring lactams 4 was identified in attempts to use O-nucleophiles. Subsequent studies focused exclusively on S-nucleophiles. These reactions gave the desired macrocyclization products 1 in high purities and good overall yields. Conformational analyses of illustrative macrocyclization products 1 via NMR, CD, and molecular simulations showed that they seem to sample both type I and type II beta-turn conformations in solution. CD studies indicate a curious relationship between the preferred conformation and the amino acids encapsulated in the macrocycles.