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Carbohydrate–lectin interactions and glycol-molecule-driven self-assembly are powerful yet challenging strategies to create supramolecular nanostructures for biomedical applications. Herein, we develop a modular approach of micellization with a small molecular mannosylated-calix[4]arene synthetic core, CA4-Man3, to generate nano-micelles, CA4-Man3-NPs, which can target cancer cell surface receptors and facilitate the delivery of hydrophobic cargo. The oligomeric nature of the calix[4]arene enables the dynamic self-assembly of calix[4]arene (CA4), where an amphiphile, functionalized with mannose units (CA-glycoconjugates) in the upper rim and alkylated lower rim, afforded the CA4-Man3-NPs in a controllable manner. The presence of thiourea units between calixarene and tri-mannose moiety facilitated the formation of a stable core with bidentate hydrogen bonds, which in turn promoted mannose receptor targeted uptake and helped in the intracellular pH-responsive release of antineoplastic doxorubicin (Dox). Physiochemical features including the stability of the nanomicelle could circumvent the undesirable leakage of the cargoes, ensuring maximum therapeutic output with minimum off-targeted toxicity. Most importantly, surface-enhanced Raman scattering (SERS) was utilized for the first time to evaluate the critical micelle concentration during the formation, cellular uptake and intracellular drug release. The present study not only provides an architectural design of a new class of organic small molecular nanomicelles but also unveils a robust self-assembly approach that paves the way for the delivery of a wide range of hydrophobic chemotherapeutic drugs.

An efficient, green and sustainable method for the oxidative C‒C coupling of ketones and primary alcohols was developed using an environmentally benign bentonite-gold nanohybrid catalyst. This heterogeneous catalyst affords diverse α, β- unsaturated ketones in excellent yields under ambient reaction conditions in the presence of Cs2CO3 as weak base. The catalyst is selective, recyclable and only water is produced as the side product. This catalytic system is well applicable for the gram scale synthesis of α, β- unsaturated ketones.

A new quinaldine-functionalized calix[4]arene receptor (QHQC) was synthesized, characterized, and analyzed for its selective sensing properties toward Hg2+ ions, and the binding event with characteristic color change can be followed by the naked eye. The sensing process is reversible, and the detection limit for Hg2+ ions is 2.95 × 10–6 M. A colorimetric solid state Hg2+ sensor was fabricated by intercalating this receptor molecule into the bentonite galleries via the ion-exchange method. This organic–inorganic hybrid sensor shows properties analogous to the receptor molecule and effectively detects Hg2+ ions rapidly with visual color change. The solid state Hg2+ sensor is economically affordable, environmentally benign, portable, reversible, and reusable.

An efficient, green and reliable method for the direct reductive amination of aldehydes was developed using an environmentally benign bentonite-gold nanohybrid catalyst. Use of this heterogeneous catalyst affords a variety of secondary amines in excellent yield under ambient reaction conditions in the presence of phenyldimethylsilane as mild hydride donor. The catalyst is recyclable, selective and is well applicable for the gram-scale preparation of secondary amines.

A facile route toward the synthesis of pentaleno(1,2- b )indoles via multicomponent reaction of indole, aldehyde, and pentafulvene is realized. The reaction proceeds through Lewis acid catalyzed [3+2] cycloaddition of in situ generated indolylmethanol and pentafulvene. This methodology provides an easy access to biologically relevant indole derivatives.

Selective C-2 functionalization of N-protected and free indoles is reported. The ruthenium-catalyzed C-2 activation of indoles provided an easy access to cyclopentenylated indoles. Hydroheteroarylated bicyclic motifs were synthesized via iridium-catalyzed C-2 activation of NH indoles. The methodology was extended to different bicyclic adducts such as diaza- or urea-derived bicyclic olefins.

A highly efficient, environmentally benign and reusable heterogeneous bentonite-gold nanohybrid catalyst was designed and synthesized. This heterogeneous catalyst could efficaciously catalyse the oxidation of organosilanes to silanols. The reaction is 98.7% atom economical and the products were obtained in excellent yield without the formation of disiloxanes as byproducts. The catalyst was also well applicable for the gram scale preparation of silanols.

A triethylene glycol modified quinoline ester ( PQTEG ) is synthesised, which acts as a colorimetric sensor for Al 3+ ions with a detection limit of 8 × 10 −7 M in acetonitrile/water (95:5, v/v) solvent system. A visible colour change from colourless to deep yellow was observed on binding of PQTEG with the metal ion. The unshared electron pairs of oxygen and nitrogen in triethylene glycol ester of quinoline provide a high binding affinity towards Al 3+ and serves as the binding site. The metal binding was further confirmed from 1 H NMR studies and IR spectroscopic studies.

An efficient stereoselective route for the synthesis of cyclopentene fused 2-pyrrolines has been established via a Pd-catalyzed C–H activation/oxidative coupling of aryl enamides with diazabicyclic olefins. The proposed two-stage mechanism was successfully proven by isolating the intermediate trans-disubstituted cyclopentene.

Introduction Octenisept (OCT; Schulke & Mayr, Nordersdedt, Germany), an antimicrobial, antibiofilm agent and a promising root canal irrigant, can be potentially combined with sodium hypochlorite (NaOCl) during endodontic treatment. The aim of this study was first to identify the precipitate formed on the interaction between OCT and NaOCl and secondly to compare its effect on dentinal tubules with that of precipitate formed on combining chlorhexidine (CHX) and NaOCl. Methods This observational study was conducted in 3 stages. Initially, the color changes and precipitate formation were assessed when the test solution 0.1% OCT and 5.2% NaOCl were mixed. Color changes were compared with those observed when 2% CHX was mixed with 5.2% NaOCl. The residue obtained on combining OCT and NaOCl was subjected to proton nuclear magnetic resonance ( 1 H NMR) and mass spectrometric (MS) analysis. In the final stage, dentinal surfaces irrigated alternatively with OCT and NaOCl were compared using scanning electron microscopy (SEM) with the dentinal surface irrigated with CHX and NaOCl. Results The OCT-NaOCl mixture changed in color from initial milky white to transparent over time, whereas the CHX-NaOCl mixture showed an immediate peach-brown discoloration. 1 H NMR and MS analysis established that the whitish precipitate obtained on combining OCT and NaOCl solutions correlated with the structure of phenoxyethanol (PE). SEM revealed dense precipitate occluding the dentinal tubules with the CHX and NaOCl group, whereas the precipitate was sparse and partially occluded in the OCT and NaOCl group. Conclusions The whitish precipitate formed with the OCT-NaOCl mixture was identified as PE, a compound already present in OCT, and it partly occluded the dentinal tubules.

An anthracene-oxyquinoline dyad (HQ-AN) is synthesized which acts as a selective fluorescent reporter for Hg(II) with a detection limit of 3.2 × 10 −6 M in acetonitrile–water system. The phenomenon of unfolding of HQ-AN from its initial folded conformation in acetonitrile–water system, selectively in the presence of Hg(II) is indicated from spectrofluorometric studies. The sensing event is monitored by the marked change in fluorescence emission occurring due to quenching of the excimer and retaining of the monomer emission of the two anthracene units in HQ-AN.

A fluorescent Zn 2+ sensor based on the 2-(2-nitrostyryl)-8-methoxyquinoline (2-nitroSQ) has been designed, synthesized, and characterized by various spectral techniques. The designed fluorophore displays high selectivity, sensitive fluorescence enhancement (13-fold), and strong binding affinity toward Zn 2+ among the various biologically significant metal ions examined in ACN–H 2 O (9:1, v/v).

Synthesis and photophysical studies of a simple and efficient dansyl-styrylquinoline conjugate (DansSQ) which shows excellent selectivity toward Fe2+ over other transition metal ions including Fe3+ are described. The fluorescent emission of DansSQ at 450 nm was enhanced upon addition of Fe2+ in the presence of common interfering metal ions in background. These studies suggest that DansSQ could be used as fluorescent sensor for Fe2+.

Calix[4]arene derived bis(spirodienone) can act as a 4π component in cycloaddition reaction with a variety of carbo- and hetero-dienophiles yielding the bisadducts in excellent to quantitative yields. Bis(spirodienone) also undergoes addition reactions with dichlorocarbene resulting in mono- and bis-dichlorocyclopropyl derived bis(spiroenones) in excellent yields.

A calix[4]arene derived bis(spirodienone) acts as the 2π component in a cycloaddition reaction with two molecules of 3,5-di-tert-butyl-1,2-benzoquinone in the [2+4] manner leading to macrocycles with a benzodioxin moiety. A theoretical rationalization of the results suggested a sterically encumbered regioselective pathway, which gives sterically crowded products.

Summary This paper describes the results of the investigations carried out on the extraction of thorium(IV) and uranium(VI) from dilute nitric acid solutions into chloroform with 1-phenyl-3-methyl-4-pivaloyl-5-pyrazolone (HPMPP) in the presence and absence of various neutral organophosphorus extractants, tributylphosphate (TBP), octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and trioctylphosphine oxide (TOPO). The results demonstrated that these metal ions were extracted into chloroform as Th(PMPP)4 and UO2(PMPP)2 with HPMPP alone and as Th(PMPP)4·S and UO2(PMPP)2·S in the presence of neutral organophosphorus extractants (S). High selectivity (S.F.=2.8×105) has been observed between thorium(IV) and uranium(VI) when extracted with HPMPP alone. The equilibrium constants of the extracted complexes have been deduced by non-linear regression analysis. The equilibrium constants of the synergistically extracted complexes have been correlated with the donor ability of the phosphoryl oxygen of the neutral organophosphorus extractants in terms of their 31P NMR chemical shifts and basicity values (K H = nitric acid uptake constant). The addition of a neutral organophosphorus extractant to the metal chelate system significantly enhances the extraction efficiency of these metal ions. Thorium(IV) and uranium(VI) complexes of HPMPP and mixtures of HPMPP and neutral organophosphorus extractants were synthesized and characterized by IR spectral data to further clarify the nature of the extracted complexes.

The reaction of 1:1 zwitterionic intermediate generated in situ from dimethyl acetylenedicarboxylate (DMAD) and cyclohexyl isocyanide with aldehydes and quinones is described. The reaction of stoichiometric amounts of DMAD, isocyanide and aldehydes afforded 2-aminofurans in good yields, while the reaction with quinones gave iminolactones.

This paper embodies the results of the investigations carried out on the extraction behavior of lanthanoids such as Nd(III), Eu(III), and Tm(III) from perchlorate solutions into chloroform with 1‐phenyl‐3‐methyl‐4‐pivaloyl‐5‐pyrazolone (HPMPP) in the presence and absence of various crown ethers (CE), 18‐crown‐6 (18C6), dicyclohexano‐18‐crown‐6 (DC18C6), and dibenzo‐18‐crown‐6 (DB18C6). The results demonstrate that these trivalent metal ions are extracted into chloroform as Ln(PMPP)3, with HPMPP alone, and in the presence of CE as Ln(PMPP)3·CE. The equilibrium constants of the extracted complexes have been determined by nonlinear regression analysis and are found to increase monotonically with decreasing ionic radii of these metal ions. The addition of a CE to the metal chelate system not only enhances the extraction efficiency but also improves the selectivities among these trivalent lanthanoids, especially in the presence of DB18C6.

Typically mono-cyclopentyl functionalized products are obtained but 2-phenyl benzimidazole (VI) furnishes the corresponding bis-cyclopentenyl derivatives under similar conditions.

Calix[4]bis(spirodienones) can perform as either 4π or 2π components in cycloaddition reactions with various carbo- and hetero-dienophiles and with 1,2-benzoquinones leading to the formation of highly functionalized macrocycles. In this Letter we report, highly regio- and stereoselective 1,3-dipolar cycloaddition reactions of a bis(spirodienone) derivative of calix[4]arene with nitrones that provide easy access to isoxazolidine derived macrocycles in excellent yields. These isoxazolidine derivatives can be considered as direct precursors of 1,3-amino alcohols.

The extraction of yttrium and some trivalent lanthanides from thiocyanate and nitrate solutions using Cyanex 923 { TRPO ) in xylene as an extractant has been investigated. It has been found that these trivalent metal ions are extracted from thiocyanate solution as M(SCN)3.n TRPO ; n in general having the values of 4 and 3 for the lighter and the heavier lanthanides respectively. On the other hand, from nitrate solutions these trivalent metal ions are extracted as M(NO3)3 3 TRPO. The equilibrium constants of the extracted complexes have been obtained by non-linear regression analysis. In both the thiocyanate and nitrate systems, the distribution ratios of trivalent lanthanides are found to increase with decreasing ionic radii and the distribution ratio of yttrium lies along with those of the middle lanthanides. The separation factors between these trivalent metal ions were evaluated and compared with those obtained using commercially important extraction reagents like tributylphosphate (TBP), trio...

Mixed-ligand chelate extraction of trivalent lanthanides such as Nd(III), Eu(III) and Lu(III) into benzene with mixtures of 4,4,4-trifluoro-1-phenyl-1,3-butanedione (HBFA) and bis-2-ethylhexyl sulphoxide (B2EHSO) or triphenylphosphine oxide (TPhPO) from thiocyanate solutions was investigated. The results demonstrate that these metal ions are extracted as Ln(BFA) 3 with HBFA alone and in the presence of a neutral oxo-donor, B2EHSO or TPhPO(S), as Ln(BFA) 3 ·S and Ln(BFA) 3 ·2S. The equilibrium constants of the above species increase monotonically with decreasing ionic radii of these metals ions. The addition of a neutral donor to the metal chelate system not only enhances the extraction efficiency but also improves the selectivity among these trivalent lanthanides. Hence this mixed-ligand system may be useful for the extraction and separation of individual lanthanides and also for the separation of lanthanides as a group from other metal ions.

Highly regio- and stereoselective Diels–Alder reactions of bis(spirodienone) derivatives of calix[4]arene with acetylenes that provide easy access to bisbicyclo[2.2.2]octenones are described.

o-Thioquinones, generated in situ from o-hydroxyphenylthiophthalimides, underwent facile [4 + 1] cycloaddition reactions with isocyanides to afford 2-imino-1,3-oxathioles.

Many plants are used in Ayurveda for the treatment of tuberculosis. Our aim was to examine if these plants possess any specific molecule that inhibits Mycobacterium tuberculosis. One of them, Kaempferia galanga, yielded an anti-TB molecule, ethyl p-methoxycinnamate (EPMC). By resazurin microtitre assay (REMA), EPMC was shown to inhibit M. tuberculosis H37Ra, H37Rv, drug susceptible and multidrug resistant (MDR) clinical isolates (MIC 0.242-0.485mM). No cross resistance was observed to any standard anti-TB drugs in the MDR strains. The compound did not inhibit any prototype bacteria tested. EPMC seems to be a potential anti-TB lead molecule.

The 1,3-dipolar species generated from diisopropylaminoisocyanide and dimethyl acetylenedicarboxylate (DMAD) is trapped with aldehydes affording substituted 3(5H)-pyrrolin-2-ones presumably via a Dimroth-type rearrangement of the initially formed furanone hydrazones in good yields.

The reactivity of calix[4]bis(spirodicnones) depends on the nature of the dienophile used. With 1,4-benzoquinones it acts as a 4π component whereas with 1,2-benzoquinones as a 2n system, yielding benzodioxin derived macrocycles in good yield. Bis(spirodienoncs) can thus perform as a diene as well as a dienophile in cycloaddition reactions.

A new thiacalix [4]arene derivative in a 1,3-alternate conformation bearing four quinolinoloxy groups through propyl chains has been synthesized, and its metal ion-binding and fluorescence-sensing properties were investigated in both THF and 10% H2O-THF systems. The designed ligand exhibited pronounced Hg2+ -selective on-off type fluoroionophoric properties among the representative transition and heavy metal ions including Cu2+. The detection limit for Hg2+ was found to be 2.0 x 10(-6) M in the mixed H2O-THF system. Detailed spectral studies including 1H NMR and MALDI-TOF mass spectroscopy reveal the unusual formation of a tetramercury complex with the ligand, in which the four propyl arms containing the quinolinoloxy groups adopt a "tetrapodand" conformation enclosing one Hg2+ ion each in the four cavities thus formed.

The reaction of 1:1 zwitterionic intermediate generated in situ from dimethyl acetylenedicarboxylate (DMAD) and cyclohexyl isocyanide with aldehydes and quinones is described. The reaction of stoichiometric amounts of DMAD, isocyanide and aldehydes afforded 2-aminofurans in good yields, while the reaction with quinones gave iminolactones.

The Rh(II)-catalyzed reaction of dimethyl diazomalonate with aryl aldehydes and beta-nitrostyrenes results in the formation of highly substituted tetrahydrofurans. The reaction may be considered to involve the Huisgen dipolar cycloaddition of the carbonyl ylide, generated from the dicarbomethoxycarbene and the aldehyde, to the beta-nitrostyrene. The diastereoselectivity of the reaction may be attributed to the concerted nature of the carbonyl ylide cycloaddition.

The 1,3-dipolar species generated from diisopropylaminoisocyanide and dimethyl acetylenedicarboxylate (DMAD) is trapped with aldehydes affording substituted 3(5H)-pyrrolin-2-ones presumably via a Dimroth-type rearrangement of the initially formed furanone hydrazones in good yields.

A novel class of efficient visible light sensitized antenna complexes of Eu3+ based on the use of a highly conjugated β-diketonate, namely, 1-(4-biphenoyl)-3-(2-fluoroyl)propanedione (HBFPD) and 1,10-phenanthroline as an ancillary ligand has been designed, synthesized, characterized and their photophysical properties (PL) investigated. PL measurement results indicated that suitably expanded π-conjugation in the complex molecules makes the excitation band red shift to the visible region and hence the Eu3+ complexes exhibit intense red emission under blue light excitation (440 nm) with a solid-state quantum yield of 32 ± 3%, which is the highest so far reported in the literature. Further, in the present work, the visible sensitized Eu3+complex has been covalently anchored to the ordered mesoporous MCM-41 via the modified HBFPD ligand for the first time to the best of our knowledge. β-Diketonate grafted to the coupling agent 3-(triethoxysilyl)propylisocyanate was used as the precursor for the preparation of mesoporous nanomaterials. MCM-41 consisting of ternary complex Eu(SiBFPD)3(phen) covalently bonded to the silica-based network, which was designated as Eu(SiBFPD)3(Phen)/MCM-41 (3), was obtained by interacting europium nitrate, SiBFPD-Na and 1,10-phenanthroline into the hybrid material via a ligand-exchange reaction. The designed material was further characterized by powder X-ray diffraction, dynamic light scattering (DLS) technique, thermogravimetric analysis, N2 adsorption-desorption, SEM, TEM, FT-IR, FT-Raman, 13C and 29Si CPMAS NMR and photoluminescence spectroscopic techniques. The hybrid material covalently bonded to MCM-41 exhibits an efficient intramolecular energy transfer process from the silylated β-diketonate to the central Eu3+, namely, the “antenna effect”, which favored a stronger red/orange intensity ratio, longer lifetime, and high thermal stability than the precursor complex.