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Some new 4-((1H-imidazol-1-yl)diarylmethyl)-5-methyl-1-aryl-1H-1,2,3-triazoles 7a-i were designed and synthesized by the one-pot reaction of diaryl-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)methanol compounds with 1H-imidazole. The new compounds 7a-i were ch

Antibiotic resistance is one of the greatest threats to modern medicine. Drugs that were once routinely used to treat infections are being rendered ineffective, increasing the demand for novel antibiotics with low potential for resistance. Here we report

The photodecomposition of azides to generate nitrenes usually requires wavelengths in the 300 nm region. In this study, we show that this reaction can be readily performed in the UVA region (368 nm) when catalyzed by Pd-decorated TiO2. In aqueous medium the reaction leads to amines, with water acting as the H source; however, in non-protic and non-nucleophilic media, such as acetonitrile, nitrenes recombine to yield azo compounds, while azirine-mediated trapping occurs in the presence of nucleophiles. The heterogeneous process facilitates catalyst separation while showing great chemoselectivity and high yields.

The copper(I)-exchanged zeolite CuI-USY proved to efficiently catalyze the direct azidation of arylboronic acids with sodium azide under simple and practical conditions, namely at room temperature under air with methanol as solvent and without any additive. This easy-to-prepare and cheap catalytic material has been demonstrated to be recyclable and the mild azidation conditions further showed good functional-group tolerance, leading to a variety of substituted (hetero)aryl azides (18 examples). Interestingly, the azidation reaction has been successfully coupled to a CuAAC reaction, thus allowing access to triazoles from arylboronic acids via a one-pot CuI-catalyzed process.

The nucleophilic iron complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) is an active catalyst in C?H-amination but also in proton-transfer catalysis. Herein, we describe the successful use of this complex as a proton-transfer catalyst in the cyclocondensation reaction between azides and ketones to the corresponding 1,2,3-triazoles. Cross-experiments indicate that the proton-transfer catalysis is significantly faster than the nitrene-transfer catalysis, which would lead to the C?H amination product. An example of a successful sequential Dimroth triazole–indoline synthesis to the corresponding triazole-substituted indolines is presented.

Chemical probes of microRNA (miRNA) function are potential tools for understanding miRNA biology that also provide new approaches for discovering therapeutics for miRNA-associated diseases. MicroRNA-21 (miR-21) is an oncogenic miRNA that is overexpressed in most cancers and has been strongly associated with driving chemoresistance in cancers such as renal cell carcinoma (RCC). Using a cell-based luciferase reporter assay to screen small molecules, we identified a novel inhibitor of miR-21 function. Following structure-activity relationship studies, an optimized lead compound demonstrated cytotoxicity in several cancer cell lines. In a chemoresistant-RCC cell line, inhibition of miR-21 via small molecule treatment rescued the expression of tumor-suppressor proteins and sensitized cells to topotecan-induced apoptosis. This resulted in a >10-fold improvement in topotecan activity in cell viability and clonogenic assays. Overall, this work reports a novel small molecule inhibitor for perturbing miR-21 function and demonstrates an approach to enhancing the potency of chemotherapeutics specifically for cancers derived from oncomir addiction.

The stereospecific photochemistry of ten N-aryl-substituted cis- or trans-Δ2-1,2,3-triazolines to form the corresponding cis- or trans-aziridines was investigated both in solution and in the solid-state. We found that photochemical reactions in the solid state are more stereospecific than in solution for the 8 crystalline Δ2-1,2,3-triazolines. Additionally, triplet sensitization for some triazolines results in triplet biradicals, which provide the more thermodynamically favored trans-aziridine regardless of the starting triazoline stereochemistry. Product analyses as a function of temperature and solvent polarity suggest that the electronic excitation of the Δ2-1,2,3-triazolines results in the formation of a 1,3-biradical intermediate.

In an attempt to arrive at more potent cytotoxic agent than the bioactive natural product betulinic acid, influence of small structural modifications of its 1, 2, 3 triazole derivatives tethered at C-28 and both C3, C-28 using click chemistry approach has been studied. The chemically characterized triazoles have been screened for in vitro cytotoxicity against four human cancer cell lines HL-60, MiaPaCa-2, PC-3 and A549 which has allowed to identify triazole derivative 28{1N (4-fluoro phenyl)-1H-1, 2, 3-triazol-4-yl} methyloxy betulinic ester having better potency profile than the parent compound with IC50 values in the range of 5-7 μM. It caused disruption of mitochondrial membrane potential, rendered Bcl-2 cleavage, Bax translocation and decrease Bcl-2/Bax ratio. These events are accompanied by activation of caspases -9, -3, which cleave the PARP-1. It also induces caspase-8, which is involved in extrinsic apoptotic pathway. Therefore, it induces apoptosis through both intrinsic and extrinsic pathways in human leukemia HL-60 cells.

One-pot, atom-economical, catalyst-free and tri-component domino reactions are applied to the diversity-oriented synthesis (DOS) of disubstituted piperazine derivatives under mild conditions with moderate to high yields. This protocol exhibits potential a

Some new (S)-1-aryl-N-(1-hydroxy-3-phenylpropan-2-yl)-5-methyl-1 H-1,2,3-triazole-4-carboxamides 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j have been synthesized and established by 1H and 13C NMR, IR, MS spectra, CHN analyses, and x-ray

Magnetically recoverable and reusable CuFe2O4 nanoparticles are shown to be highly efficient catalysts for the one-pot synthesis of biologically important 1,4-diaryl-1,2,3-triazoles starting from boronic acids, sodium azide, and acetylenes. The use of aqueous reaction medium at room temperature, the low cost and facile recovery of the catalyst by application of an external magnetic field, and consistently high catalytic efficiency for at least three consecutive cycles renders the protocol operationally attractive. Magnetic and catalytically competent CuFe 2O4 nanoparticles proved to be highly efficient in the three-component synthesis of 1,4-diaryl-1,2,3-triazoles, a class of compounds that has been recognized for its anticancer activity. Copyright

1,2,3-Triazoles have been extensively studied as compounds possessing important biological activities. In this work, we describe the synthesis of ten 2-(1-aryl-1H- 1,2,3-triazol-4-yl)propan-2-ols via copper catalyzed azide alkyne cycloaddition (CuAAc or click chemistry). Next the in vitro antifungal activity of these ten compounds was evaluated using the microdilution broth method against 42 isolates of four different Candida species. Among all tested compounds, the halogen substituted triazole 2-[1-(4-chlorophenyl)-1H- (1,2,3)triazol-4-yl]propan-2-ol, revealed the best antifungal profile, showing that further modifications could be done in the structure to obtain a better drug candidate in the future.

A series of 3-(1 -aryl-1 H-1,2,3-triazol-4-yl)-6-phenyl-1,2,4-triazines were synthesized by the reaction of 1-aryl-1tf-1,2,3-triazole-4-carbohydrazide with 2-bromo-1- phenylethanone and sodium acetate in refluxed EtOH and AcOH. Their structures were chara

Rate constants for acid-catalyzed dehydration of cis-2-substituted 1,2-dihydro-naphthols are well correlated by the Taft relationship log k = -0.49 - 8.8σI, with minor negative deviations for OH and OMe. By contrast the trans substituents show a poor correlation with σI and in most cases react more slowly than their cis isomers. The behavior is consistent with rate-determining formation of a 2-substituted carbocation (naphthalenium ion) intermediate that for cis reactants possesses a 2-C-H bond suitably oriented for hyperconjugation with the charge center. For the trans isomers the 2-substituent itself is oriented for hyperconjugation in the initially formed conformation of the cation. It is argued that k cis/ktrans rate ratios for substituents (Me, 8.4; Bu t, 12.7; Ph, 3.8; NH3+, 160; OH, 440) reflect their hyperconjugating ability relative to hydrogen. Faster reactions of trans isomers are observed for substitutents known (RS, N3) or suspected (EtSO, EtSO2) of stabilizing the cation by a π or σ neighboring group effect. The good Taft correlation is taken to indicate that cis substuents are reacting normally, differentiated only by their inductive effects. The slower reactions of the trans isomers are the judged to be "abnormal". This is confirmed by comparing effects of cis and trans β-OH substituents on the reactivities of dihydro phenols, naphthols, and phenanthrols. Whereas kH/kOH for cis substituents varies by less than 8-fold and is consistent with the influence of an inductive effect of the OH group (kH/kOH ≈ 2000), kH/k OH for the trans substituents varies by 3 orders of magnitude, reflecting the additional influence of the lesser hyperconjugating ability of a C-OH bond compared to a C-H bond. The magnitude and variation of this difference is consistent with C-H hyperconjugation conferring aromatic character on the arenium ions

In a DCC-mediated coupling 2,3,4,6-tetra-O-acetyl-β-d- glucopyranosylamine and propiolic acid gave N-propynoyl-2,3,4,6-tetra-O-acetyl- β-d-glucopyranosylamine which was transformed by 1,3-dipolar cycloadditions with aromatic azides and nitrile-oxides to t

We report here the one-pot synthesis of 1,2,3-triazoles of arylboronic acids in water. An efficient method has been developed for the synthesis of 1,2,3-triazoles via a one-pot reaction of an arylboronic acid with sodium azide in the presence of Cu2-β-CD (CD = Cyclodextrin) as a nanocatalyst in water followed by a click cyclization reaction with an alkyne at room temperature in air without any additives. This method is simple, rapid, and high yielding.

Montmorillonite KSF clay supported CuO nanoparticles efficiently catalyzes one-pot aromatic azidonation of aryl boronic acids followed by regioselective azide-alkyne 1,3-dipolar cycloaddition (CuAAC) reaction producing corresponding 1-aryl-1,2,3-triazole derivatives at room temperature in excellent yields without use of any additives. Investigations on mechanism of CuAAC revealed that sodium azide, which is used as azidonating reagent in one-pot protocol reduces Cu(II) to click-active Cu(I). The catalytic efficiency of another Cu(II) source CuSO4 in combination with NaN3 for this one-pot CuAAC protocol, further supported our mechanism. This is the first report for use of Cu(II)/NaN3 catalytic system for CuAAC protocol. The clay-Cu(II) catalyst being ligand-free, leaching-free, easy to synthesize from inexpensive commercially available precursors, recyclable, and environmentally friendly will be highly useful for economical synthesis of 1,4-disubstituted 1,2,3-triazoles.

A simple and general copper-catalyzed method has been developed for transformations of various functional groups (i I, i N3, i SO2R, i OH, i NH2, and i NO 2) on aromatic rings from arylboronic acids in water under air. The protocol uses cheap and readily available inorganic salts (KI, NaN3, NaSO2R, NaOH, NaNO2) and aqueous ammonia as the functional-group sources, simple Cu2O/NH3 as the catalyst system, environmentally friendly water as the solvent, and oxygen in air as the oxidant. Importantly, the copper catalyst system in water was recyclable. This study should provide a useful strategy for interconversions of the functional groups on aromatic rings.

5-(O-Perbenzoylated-β-d-glucopyranosyl)tetrazole was obtained from O-perbenzoylated-β-d-glucopyranosyl cyanide by Bu3SnN 3 or Me3SiN3-Bu2SnO. This tetrazole was transformed into 5-ethynyl- as well as 5-chloromethyl-2-(O-perbenzoylated- β-d-glucopyranosyl)-1,3,4-oxadiazoles by acylation with propiolic acid-DCC or chloroacetyl chloride, respectively. The chloromethyl oxadiazole gave the corresponding azidomethyl derivative on treatment with NaN3. These compounds were reacted with several alkynes and azides under Cu(I) catalysed cycloaddition conditions to give, after removal of the protecting groups by the Zemple?n protocol, β-d-glucopyranosyl-1,3,4-oxadiazolyl-1,2,3- triazole, β-d-glucopyranosyl-1,2,3-triazolyl-1,3,4-oxadiazole, and β-d-glucopyranosyl-1,3,4-oxadiazolylmethyl-1,2,3-triazole type compounds. 5-Phenyltetrazole was also transformed under the above conditions into a series of aryl-1,3,4-oxadiazolyl-1,2,3-triazoles, aryl-1,2,3-triazolyl-1,3,4- oxadiazoles, and aryl-1,3,4-oxadiazolylmethyl-1,2,3-triazoles. The new compounds were assayed against rabbit muscle glycogen phosphorylase b and the best inhibitors had inhibition constants in the upper micromolar range (2-phenyl-5-[1-(β-d-glucopyranosyl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 36: Ki = 854 μM, 2-(β-d-glucopyranosyl)-5-[1-(naphthalen-2- yl)-1,2,3-triazol-4-yl]-1,3,4-oxadiazole 47: Ki = 745 μM).

Several new N-[4-acetyl-4,5-dihydro-5-(1-aryl-5-methyl-1H-1,2,3-triazol-4- yl)-5-methyl-1,3,4-thiadiazol-2-yl]acetamide derivatives have been synthesized and the structures of these compounds have been established by MS, IR, CHN and 1H NMR spec

Benzene-cis- and trans-1,2-dihydrodiols undergo acid-catalyzed dehydration at remarkably different rates: kcis/ktrans = 4500. This is explained by formation of a β-hydroxycarbocation intermediate in different initial conformations, one of which is stabilized by hyperconjugation amplified by an aromatic no-bond resonance structure (HOC6H6 + HOC6H5 H+). MP2 calculations and an unfavorable effect of benzoannelation on benzenium ion stability, implied by pKR measurements of -2.3, -8.0, and -11.9 for benzenium, 1-naphthalenium, and 9-phenanthrenium ions, respectively, support the explanation.

Aromatic azides are inert toward triethylsilane under thermal conditions in the presence of a radical initiator, but in the presence of additional catalytic amounts of tert-dodecanethiol, they afford anilinosilanes and thence the corresponding anilines in virtually quantitative yields.

The cyclization of 1-amino-2-mercapto-5-[1-(4-ethoxyphenyl)-5-methyl-1,2,3- triazol-4-yl]-1,3,4-triazole which was synthesized from p-ethoxyaniline with various triazole acid in absolute phosphorus oxychloride yields 3,6-bis(1,2,3-triazolyl)-s-triazolo[3,

This article provides insight into the various factors by which electronegative substituents affect the kinetic acidity of arenes and, more specifically, naphthalenes. Both 1- and 2-(trifluoromethyl)naphthalenes were consecutively treated with an organometallic or lithium dialkylamide-type base and carbon dioxide. Due to single electron-transfer triggered side reactions, the yields of (trifluoromethyl)naphthoic acids were moderate to poor. 1-(Trifluoromethyl)naphthalene was exclusively attacked at the 2-position as expected. The 2-isomer reacted with tert-butyllithium in the presence of potassium tert-butoxide solely at the 1-position, but with sec-butyllithium in the presence of N,N,N′,N′-tetramethylethylene-diamine concomitantly at the 3- and 4-positions. Authentic samples of the key acids 1, 4, 5 and 6 were prepared based on independent, unambiguous methods.

Photochemical rearrangement of 1,6-(N-aryl)aza-[60]fulleroids (1) to 1,2-(N-arylaziridino)-[60]fullerenes (2) depends on the N-aryl substituents remote from the reaction center. A systematic kinetic study of the N-substituents discloses a decrease in the reaction rates of the photochemical rearrangement in the order 1-naphthyl (1b) > 1-pyrenyl (1d) > phenyl (1a) > 2-naphthyl (1e). The large substituent effect in the rates, which vary by ca. 2200-fold, is interpreted in terms of changes in the reaction mechanisms. The fast photochemical rearrangement of derivatives 1b,d proceeds through the normal triplet states of 1; in the case of 1b, triplet sensitization by the product 2b also operates. For the slow rearrangement rates of 1a.c, nanosecond transient absorption spectroscopy reveals that different triplet states participate, namely, electron transfer between the N-aryl substituent and the fullerene.

Novel compounds, their salts and compositions related thereto having activity against mammalian factor Xa are disclosed. The compounds are useful in vitro or in vivo for preventing or treating coagulation disorders.

Lithium derivatives of varied aromatic, heterocyclic, aliphatic, and alicyclic primary amines react efficiently with azidotris(diethylamino)phosphonium bromide in THF at low temperatures to give azides, lithium bromide, nitrogen, and tris(diethylamino)pho

Novel compounds, their salts and compositions related thereto having activity against mammalian factor Xa are disclosed. The compounds are useful in vitro or in vivo for preventing or treating coagulation disorders.