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A palladium-catalyzed, solvent-dependent, intramolecular oxypalladation-initiated chemodivergent approach was established for the synthesis of functionalized benzazepines and tetrahydroquinolines.

A microwave-assisted, aminopalladation-initiated domino reaction of 2-alkynylanilines having a pendant α,β-unsaturated carbonyl moiety was established for the synthesis of 5,10-dihydroindeno[1,2-b]indoles.

A tandem formal [3+3]-cycloaddition/oxidation between chalcones and β-enamine esters, employing iodine as a catalyst, was developed for the construction of various substituted m-terphenyls. A wide range of chalcones and β-enamine esters were tested under metal- and solvent-free conditions for the synthesis of substituted m-terphenyls in good to excellent yields in the presence of sulfur as an oxidant. This reaction proceeds with the formation of four new bonds and one new ring, with a high atom economy.

A microwave-assisted, copper-catalyzed, one-pot, two-step synthesis of benzofused[1,6]naphthyridines is established.

The design and synthesis of amphiphilic molecules play a crucial role in fabricating smart functional materials via self-assembly.

Over the past few decades, the scientific community is actively involved in the development of edible structuring agents suitable for food, cosmetics, agricultural, pharmaceutical, and biotechnology applications. In particular, edible oil structuring using simple amphiphiles would be the best alternative for the currently used trans and saturated fatty acids, which cause deleterious health effects and cardiovascular problems. In this report, we have made an attempt to address the aforementioned consequences, by synthesizing a new class of structuring agents by a judicious combination of δ-gluconolactone and ricinoleic acid, compounds classified as GRAS, using simple steps in good yield. To our delight, the synthesized glycolipids self-assemble in a wide variety of vegetable oils and commercially viable glycerol, ethylene glycol, and polyethylene glycol via various intermolecular interactions to form a gel. The morphology of molecular gels was investigated by optical microscopy and FESEM analysis, which reveal the existence of a tubular architecture with a diameter ranging from 75 to 150 nm. Rheological studies disclosed the viscoelastic nature, thermal processability, and thixotropic behavior of both oleogels and organogels. Altogether, self-assembled oleogel and organogel reported in this paper would potentially be used in food, agricultural, cosmetics, pharmaceutical, and biotechnological applications.

Globally, wound infections are considered as one of the major healthcare problems owing to the delayed healing process in diabetic patients and microbial contamination. Thus, the development of advanced materials for wound skin repair is of great research interest. Even though several biomaterials were identified as wound healing agents, gel-based scaffolds derived from either polymer or small molecules have displayed promising wound closure mechanism. Herein, for the first time, we report an injectable and self-healing self-assembled anesthetic oleogel derived from glycolipid, which exhibits antibiofilm and wound closure performance in diabetic rat. Glycolipid derived by the reaction of hydrophobic vinyl ester with α-chloralose in the presence of novozyme 435 undergoes spontaneous self-assembly in paraffin oil furnished an oleogel displaying self-healing behavior. In addition, we have prepared composite gel by encapsulating curcumin in the 3D fibrous network of oleogel. More interestingly, glycolipid in its native form demoed potential in disassembling methicillin-resistant Staphylococcus aureus, methicillin-susceptible Staphylococcus aureus, and Pseudomonas aeruginosa biofilms. Both oleogel and composite gel enhanced the wound skin repair in diabetic induced Wistar rats by promoting collagen synthesis, controlling free radical generation and further regulating tissue remodeling phases. Altogether, the reported supramolecular self-assembled anesthetic glycolipid could be potentially used for diabetic skin wound repair and to treat bacterial biofilm related infections.

A sequential three-component cascade process was developed for the synthesis of bridged tetrahydroquinolines and chromanes bearing 2,6-methanobenzo[d][1,3]diazocine and 2,6-methanobenzo[g][1,3]oxaz...

A tandem amidation/epoxidation sequence between various substituted chalcones and N,N-dimethylformamide (DMF) for the synthesis of trisubstituted epoxides employing N-heterocyclic carbene catalysis was developed. This reaction was performed under metal-free conditions in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant. Trisubstituted epoxides bearing a ketone and an amide functionality (N,N-dimethyl formyl group) were synthesized starting from a wide range of chalcones in moderate to good yields with excellent diastereoselectivity.

A solvent-dependent chemodivergent approach was established for the synthesis of 6,12-methanodibenzo[b,f][1,5]diazocin-13-ylmethanones and 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines involving two distinct multicomponent processes under basic conditions. The AB2 three-component and A2B2 four-component reactions between 2-aminoarylaldehydes and aryl methyl ketones under basic conditions afforded 6,12-methanodibenzo[b,f][1,5]diazocin-13-ylmethanones (up to 95% yield) and trisubstituted tetrahydroquinolines (up to 84% yield), respectively, based on the nature of the solvent employed. The skeletal diversity and complexity were attained in these high atom- and step-economical processes by creating four new bonds in a single synthetic operation from readily available simple starting materials.

An efficient Pd(II)-catalyzed cascade approach was established for the synthesis of 9-chloro-1H-benzo[b]furo[3,4-e]azepin-1-ones starting from N-propargyl arylamines having a pendant α,β-unsaturate...

A palladium catalyzed cascade process involving syn-chloropalladation, intramolecular olefin insertion, and oxidative C-Cl bond formation reactions was demonstrated for the synthesis of dichlorinated tetrahydroquinolines in high yields (up to 93%). The N-propargyl arylamines having a tethered α,β-unsaturated carbonyl moiety underwent a regioselective syn-chloropalladation followed by a Heck-type reaction to deliver the tetrahydroquinoline scaffold. The rare insertion of the second chlorine atom was rationalized comprising a Pd

Tetrahydroquinoline is one of the most important simple nitrogen heterocycles, being widespread in nature and present in a broad variety of pharmacologically active compounds. This Review summarizes the progress achieved in the chemistry of tetrahydroquinolines, with emphasis on their synthesis, during the period from mid-2010 to early 2018.

Flavonoids and their derivatives have been extensively studied for their pharmaceutical applications due to their antioxidant and anti-inflammatory properties. The coordination complexes of several flavonoids have demonstrated DNA binding ability that can confer anticancer properties. The structure of the flavonoid has a pronounced influence on its pharmacological properties. Herein we report the synthesis and characterization of alkylated quercetin and its complex with gadolinium. The structure of the complex was confirmed using spectroscopic techniques. The ability of the gadolinium–alkylated quercetin complex to serve as a magnetic contrast agent was compared with gadolinium–quercetin complex. The quercetin–gadolinium complex was found to exhibit better contrast property with a relaxivity of 0.2952 μg mL–1 s–1 when compared to the gadolinium complex of alkylated quercetin. This difference primarily arises due to the greater hydrophobicity of the alkylated quercetin complex that restricts access of wate...

The quinoline scaffold is present in numerous alkaloids and bioactive compounds often associated with remarkable biological properties. Common approaches to assemble the quinoline ring system include the Skraup, Friedlander, Combes, Doebner-von Miller, and Conrad-Limpach reactions, but the utility of these synthesis methods is limited by their harsh acidic and extreme reaction conditions. Similarly, the isoquinoline moiety is a key structural feature of many natural products and pharmacologically relevant compounds. Owing to the significance of these scaffolds in drug discovery and medicinal chemistry, the development of new methodologies for the synthesis of quinoline and isoquinoline remains a very active field of research. Copper-catalyzed annulation reactions have emerged as powerful and promising approaches for the synthesis of diverse nitrogen heterocycles, including quinolines and isoquinolines. Moreover, copper salts, being economical and having low toxicity, have received significant attention as an inexpensive alternative to precious transition-metal catalysts. Consequently, this chapter summarizes the copper-catalyzed synthetic methodologies to access quinolines and isoquinolines.

Palladium(II)-catalyzed regioselective syn-chloropalladation and anti-acetoxypalladation-initiated cascade processes were developed for the synthesis of functionalized tetrahydroquinolines. A series of N-propargyl arylamines tethered with an α,β-unsaturated carbonyl scaffold underwent atom economical cascade reactions to deliver chloro- and acetoxy-substituted tetrahydroquinolines bearing an exocyclic double bond in high yields. A mechanism is proposed for these cascade processes involving a sequential syn-chloropalladation or anti-acetoxypalladation of alkynes followed by intramolecular olefin insertion (6-exo-trig) and protonolysis steps. The reaction was completely regioselective and the terminal aryl/alkyl group of the propargyl moiety dictated the regiochemistry of the initial nucleopalladation. The role of the bidentate nitrogen ligand is crucial to trigger the acetoxypalladation-initiated cascade sequence in contrast to the chloropalladation-initiated process.

A sequential three-component cascade process was developed for the synthesis of bridged tetrahydroquinolines and chromanes bearing 2,6-methanobenzo[

An oxidant-free three-component synthesis of biologically significant 7-amino-6H-benzo[c]chromen-6-ones was established involving a Sc(OTf)3 catalyzed three-component reaction between primary amines, β-ketoesters and 2-hydroxychalcones under green conditions. In this strategy, both the B and C rings of 6H-benzo[c]chromen-6-ones were constructed simultaneously starting from acyclic precursors by generating four new bonds including two C–C, one C–N and one C–O in a single synthetic operation. The mechanism of this sequential cascade process involves the initial formation of a β-enaminone intermediate followed by Michael addition with 2-hydroxychalcone, intramolecular cyclization, dehydration, lactonization and aromatization steps. Unlike the related literature approaches, this reaction delivered the products without the addition of any external oxidants to achieve the key aromatization step.

The implementation of a novel approach in the development of stimuli responsive supramolecular gels is an important objective that challenges material chemists and biologists in order to access an exclusively new category of smart materials. In this report, non-toxic, bio-based amphiphilic glycosylfurans were designed and synthesized using a biocatalyst, Novozyme 435, an immobilized lipase B from Candida antarctica. The self-assembly of these compounds generated oleogels and hydrogels. To our delight, these bio-based amphiphilic glycosylfurans furnished an in situ stimuli responsive hydrogel with simultaneous encapsulation of various biologically relevant molecules and ions. For the first time we are reporting hydrogelation via in situ molecular tuning followed by a self-sorting mechanism. The sol-to-gel transition in the reported smart hydrogel was observed by the addition of acidic buffer of pH 4.0, which could be potentially used for the stimuli responsive delivery of a signalling molecule, H2S and other biomolecules that regulate many physiological and pathological processes.

We designed and synthesised coumarin-tris derivatives from a renewable resource and well characterized them using different spectral techniques. The self-assembly of coumarin-tris amphiphiles into hydrogels was examined relative to the molecular structure of the amphiphiles. The reversible morphological transition from nanofibers to vesicles and nanotubes has been observed, upon pH variation. Reversible processes and self-assembled structures such as gel, vesicle and nanotube formation have been investigated using optical microscopy and high resolution transmission electron microscopy (HRTEM). 1H NMR and XRD studies clearly suggest that the π–π stacking interactions and hydrogen bonding were the driving force for the process of gelation. The flow behaviour of the hydrogel has been identified using rheological measurements. More importantly, the chemopreventive drug curcumin has been encapsulated into the gel and subsequent release has been achieved by a gel-to-sol transition induced by pH and Fe3+ metal ion stimuli. The reported hydrogel could play a substantial role in the development of new generation stimuli responsive drug delivery systems for in vivo formulations.

A metal-free, regioselective strategy for the synthesis of 3-arylimidazo[1,2-a]pyridines from β-nitrostyrenes and 2-aminopyridines using triethylamine as the catalyst and H2O2 (30% aq.) as the oxidant is reported. The use of an inexpensive base and facile reaction conditions make this strategy a practical alternative for the synthesis of 3-arylimidazo[1,2-a]pyridines.

PurposeThe purpose of this paper is to examine why firms governed by the same environmental management standards within an industry exhibit contrasting responses, with some adhering to the letter and others achieving the spirit behind the standards.Design/methodology/approachUsing Arenaet al.(2010) as an analytical schema to examine the institutional dynamics behind such contrasting responses, the paper analyses archival and interview data relating to firm strategy, control technology and human expertise in two contrasting Australian forestry firms.FindingsThe embedding and decoupling of environmental standards with a firm’s environmental management practices is influenced, first, by the extent to which founder directors and senior management integrate environmental responsibility with the underlying business motives and, second, by the use of organisational beliefs and values systems to institutionalise the integrated strategic rationality throughout the firm. Finally, informed by the institutionalised strategic rationality, the participation and expertise of actors across the organisational hierarchy determine the level to which the design and execution of the eco-control technologies move beyond merely monitoring compliance, and act to facilitate continuous improvement, knowledge integration and organisational learning at the operational level.Originality/valueThis paper responds to institutional theorists’ call for a holistic explanation that considers the interactions among several intra-organisational factors to explain the dynamics behind why some firms decouple while others do not, even though the firms exist in the same social and regulatory context.

In developing countries, wounds are a major health concern and pose a significant problem. Hence, the development of new materials that can act as scaffolds for in situ tissue regeneration and regrowth is necessary. In this report, we present a new class of injectable oleogel and composite gel derived from glycolipids that provide reversible interlinked 3D fiberous network architecture for effective wound closure by tissue regrowth and regeneration. Glycolipids were derived from α-chloralose and various vinyl esters using Novozyme 435, an immobilized lipase B from Candida antarctica as a catalyst, in good yield. These glycolipids undergo spontaneous self-assembly in paraffin oil to form an oleogel, in which curcumin was successfully incorporated to generate a composite gel. Morphological analysis of the oleogel and composite gel clearly revealed the formation of a 3D fiberous network. Rheological investigation revealed the thermal and mechanical processability of the oleogel and composite gel under various experimental conditions. Interestingly, the developed injectable oleogel and composite gel are able to accelerate the wound healing process by regulating the overlapping phases of inflammation, cell proliferation and extracellular matrix remodelling. Since chloralose displays anesthetic properties, this study will establish a new strategy to develop anesthetic wound healing oleogels in the future.

The efficiency of N,N-dimethylformamide (DMF) in the N-heterocyclic carbene-catalyzed Mannich reaction for the synthesis of β-amino ketones has been demonstrated. This strategy involves oxidative coupling of aryl methyl ketones and 2-aminopyridines in the presence of DMF. The reaction does not require pre-functionalization of the substrates, thus making it a practically applicable approach for the generation of β-amino ketones. The reaction requires the use of tin(II) chloride dihydrate (SnCl2⋅2 H2O) as Lewis acid in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant. The reaction was tolerant to several aryl methyl ketones, including 2-acetylnaphthalene and acetylthiophene. Various substituted 2-aminopyridines react with acetophenone to give the desired β-amino ketones in good yields.

Water is not flammable, has no smell, is nontoxic and is easily separated from the products of organic reactions. Furthermore, when used as a reaction medium it often enhances the rate and selectivities of many organic reactions or leads to alternative reaction modes. Due to these features, stereoselective organocatalysis in water has attracted much interest from synthetic chemists. We summarize in this chapter the main developments on stereoselective reactions performed in water and using proline or proline derivatives as catalysts. Reactions catalyzed by solid-supported proline derivatives are also discussed in detail.

The new motif – α,α-difluoromethyl thioamide – has been assembled starting from isothiocyanate (as thioamide precursor) and a formal difluoromethyl-carbanion generated from commercially available TMSCHF2. Upon proper activation of this reagent with potassium tert-amylate, the high-yielding transfer of the difluorinated nucleophile takes place under high chemocontrol. Various sensitive functionalities (e.g. ester, nitrile, nitro, azido groups) can be accommodated across the isothiocyanate core, thus allowing a wide scope. The methodology is highly flexible and adaptable to prepare analogous α,α-difluoromethyl oxoamides by conveniently using isocyanates as the electrophilic building-blocks.

An oxidant-free three-component synthesis of biologically significant 7-amino-6

An efficient Pd(II)-catalyzed cascade approach was established for the synthesis of 9-chloro-1

An efficient green protocol for the synthesis of complex hybrid heterocycles containing [1,6]-naphthyridine and coumarin/pyrazole moieties was established, involving an intramolecular [4 + 2] hetero Diels–Alder reaction as the key step. The biologically significant 12,13-dihydro-6H-benzo[h]chromeno[3,4-b][1,6]naphthyridin-6-ones and 6,10-dihydro-5H-benzo[h]pyrazolo[3,4-b][1,6]naphthyridines were synthesized starting from 2-(N-propargylamino)-arylaldehydes and 3-aminocoumarins or 3-methyl-1-aryl-1H-pyrazol-5-amines in the presence of an Amberlyst-15 catalyst in PEG-200 in good yields. The easy access to diverse complex molecules in a single operation from readily available starting materials, a commercially available, transition metal-free and recyclable catalyst, the use of a green solvent, a very high atom economy and the release of water as the only side product are the highlights of this protocol.

The synthesis of spirooxindoles bearing tetrahydro-4 H-cyclopenta[ b]furan framework was established starting from isatin-derived aldehydes and 2 equiv of 1,3-dicarbonyl compounds involving a piperidine-catalyzed ABB' three-component domino process. This reaction was highly diastereoselective affording a single diastereomer of spirooxindoles with five consecutive asymmetric carbons including spiro and tetrasubstituted carbon centers. In addition, this waste-free (-2H

This research note provides additional empirical evidence relating to the performance effects of diagnostic and interactive control, both in isolation and in combination with an enabling approach to control. Drawing on data from a survey of 221 Australian firms, the findings suggest that while diagnostic eco-control has no direct influence on environmental performance, its interaction with an enabling approach yields a positive complementary effect. However, while interactive eco-control and an enabling approach are independently associated with environmental performance, their interaction effect is not significant, which implies that their combination may not necessarily be value-adding. Finally, the results also indicate a non-linear (inverse U-shaped) association between an enabling approach to control and environmental performance, which implies that an increased emphasis on an enabling approach may lead to diminishing marginal returns.