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An efficient dual Pd-catalytic system was developed for one-pot synthesis of 3-sulfenylindoles via C–C, C–N and C–S bond construction directly from unactivated 2-iodo(NH)anilines under mild reaction conditions.

The 2-hydroxystyrylbenzene scaffold is found in various compounds that are widely applicable in medicinal chemistry as well as material chemistry. Here, a successful attempt is made to develop a one-pot protocol for the synthesis of 2-hydroxystilbene derivatives via hydrolysis of natural coumarins followed by in situ decarboxylative Heck coupling with haloarenes. Fine tuning of the reaction conditions allowed exclusive formation of 2-hydroxystyrylbenzenes over other possible side products, i. e., benzofuran/substituted coumarins.

In pursuit of antimalarial drug, to overcome the drug resistance and the risk of drug-drug interactions, the chalcone hybrids and their structure-activity relationship for the antimalarial activity studied against chloroquine sensitive as well as multi-drug resistant strain of Plasmodium falciparum. Our study has revealed that 7- Chloro quinoline groups on chalcone increase anti-malarial potency, while the positional interchange of these groups decreases the efficacy. Particularly, chloro-substituent provided potent analogues which were easily derived from naturally available vanillin. The most active compounds were relatively non-toxic and structure-activity relationship study suggested that 7-chloroquinoline group when attached with triazole linkage increased the antimalarial potential of the compound against both chloroquine-sensitive and multidrug resistant strain.

Bifunctionalized indoles are an important class of biologically active heterocyclic compounds and potential drug candidates. Because of the lack of efficient synthetic methods, one pot cascade synthesis of these compounds is rare and remains a challenge. To expand this field, we herein disclose a step-economical and temperature tunable strategy wherein the synergistic effect between [hmim]Br-ArSO2Cl leads exclusively to the formation of 3-arylthio indole via sulfenylation of indole at room temperature, while heating the reaction mixture at 50 °C provided an unexpected 2-halo-3-arylthio indole with construction of C-S and C-S/C-X (X = Cl and Br) bonds without addition of any external halogenating agent via cascade sulfenylation-halogenation reactions under metal-oxidant-base-free conditions. Further, insight into the reaction mechanism provides an unprecedented observation wherein the synergistic interaction between [hmim]Br-ArSO2X in the presence of a catalytic amount of water generates arylsulfonic anhydride (ArSO2)2O in situ as a new sulfur source along with the formation of [hmim]PTS as probed by NMR, ESI-MS, DART-MS, and HPLC studies. Notably, the mixture of bifunctionalized 2-halo(Br/Cl)-3-arylthio indole was smoothly diversified with privileged heterocycle triazole to provide 2-(1 H-triazole-1-yl)-3-arylthio indole, which is an analogue of the potent indole-based anticancer agent.

Gliomas are lethal and aggressive form of brain tumors with resistance to conventional radiation and cytotoxic chemotherapies; inviting continuous efforts for drug discovery and drug delivery. Interestingly, small molecule hybrids are one such pharmacophore that continues to capture interest owing to their pluripotent medicinal effects. Accordingly, we earlier reported synthesis of potent Styryl-cinnamate hybrids (analogues of Salvianolic acid F) along with its plausible mode of action (MOA). We explored iTRAQ-LC/MS-MS technique to deduce differentially expressed landscape of native & phospho-proteins in treated glioma cells. Based on this, Protein-Protein Interactome (PPI) was looked into by employing computational tools and further validated in vitro. We hereby report that the Styryl-cinnamate hybrid, an analogue of natural Salvianolic acid F, alters key regulatory proteins involved in translation, cytoskeleton development, bioenergetics, DNA repair, angiogenesis and ubiquitination. Cell cycle analysis dictates arrest at G0/G1 stage along with reduced levels of cyclin D; involved in G1 progression. We discovered that Styryl-cinnamate hybrid targets glioma by intrinsically triggering metabolite-mediated stress. Various oncological circuits alleviated by the potential drug candidate strongly supports the role of such pharmacophores as anticancer drugs. Although, further analysis of SC hybrid in treating xenografts or solid tumors is yet to be explored but their candidature has gained huge impetus through this study. This study equips us better in understanding the shift in proteomic landscape after treating glioma cells with SC hybrid. It also allows us to elicit molecular targets of this potential drug before progressing to preclinical studies.

Staphylococcus aureus is a WHO Priority II pathogen for its capability to cause acute to chronic infections and to resist antibiotics, thus severely impacting healthcare systems worldwide. In this context, it is urgently desired to discover novel molecules to thwart the continuing emergence of antimicrobial resistance. Disulphide containing small molecules has gained prominence as antibacterials. As their conventional synthesis requires tedious synthetic procedure and sometimes toxic reagents, a green and environmentally benign protocol for their synthesis has been developed through which a series of molecules were obtained and evaluated for antibacterial activity against ESKAPE pathogen panel. The hit compound was tested for cytotoxicity against Vero cells to determine its selectivity index and time-kill kinetics was determined. The activity of hit was determined against a panel of S. aureus multi-drug resistant clinical isolates. Also, its ability to synergize with FDA approved drugs was tested as was its ability to reduce biofilm. We identified bis(2-bromophenyl) disulphide (2t) as possessing equipotent antimicrobial activity against S. aureus including MRSA and VRSA strains. Further, 2t exhibited a selectivity index of 25 with concentration-dependent bactericidal activity, synergized with all drugs tested and significantly reduced preformed biofilm. Taken together, 2t exhibits all properties to be positioned as novel scaffold for anti-staphylococcal therapy.

Indole is an important structural motif of various drugs, therapeutic leads besides its prevalence in numerous natural products, agrochemicals, perfumery, and dyes. More than 200 indole derivatives have already been marketed as drugs or are under advanced stages of clinical trials. Owing to such a huge potential, continuous efforts are being put forward to construct or diversify this scaffold. This chapter provides an overview of various recently developed methodologies for the construction of indole core via C–H bond activation/functionalization. In particular, Pd- and Ru-mediated cyclization strategies involving Csp2-H functionalization of monofunctionalized arene substrates with the unsaturated bond of alkene and alkyne are highlighted herein. Also, late-stage diversification of indole system (C4–C7 position) via direct C–H activation is covered. Furthermore, the mechanistic aspects of some of these reactions are discussed as well.

In this paper, a biocatalytic route is described wherein PPL, lipase from porcine pancreas, in conjunction with water on reaction with different thiophenols and styrene oxides undergo thiolysis with C-S bond formation without the use of any metal catalysts, oxidants, bases, additives or organic solvents towards formation of β-hydroxysulfides in good to excellent yields with high regioselectivity at room temperature. Furthermore, PPL also facilitates thiophenols to undergo hydrothiolation with styrenes or phenylacetylenes in sole water and thus forming linear thioethers or vinylsulfides respectively via C–S bond formation. In addition to the straightforward and atom-efficient protocol, a gram-scale synthesis of β-hydroxysulfide and recyclability for three consecutive cycles without decrease in efficiency of PPL make our biocatalytic protocol for constructing C–S bond highly valuable from both environmental and economic viewpoints than traditional chemical practices.

A concise, one pot and regioselective access to (E)-distyrylbenzenes (DSBs) from arylhalide and secondary phenylenediethanol, a stable precursor for in situ generation of divinylbenzene (DVB) to avoid its polymerization, is described for construction of double C C bond formation via tandem double-dehydrative-double-Heck (D-D-D-H) reaction using Palladium and ionic liquid [hmim]Br as a cooperative catalyst. It is noteworthy that this pot-economy approach also provides direct synthesis of hydroxylated distyrylbenzenes without requirement of protection-deprotection strategy. Importantly, the synthesized DSBs are tested for their protective activity against β amyloid reduction, acetylcholine esterase inhibition, lipid lowering and reactive oxygen species (ROS) reduction properties in transgenic Caenorhabditis elegans model wherein 1,3-bis((E)-4-(trifluoromethyl)styryl)benzene (5c) is found to be active across all above factors thus presenting lead molecule within multi-target-directed ligands (MTDLs) approach. Molecular docking studies were also performed to understand the interactions of potent DSBs with receptors.

This review summarizes the metal-catalyzed approaches for the synthesis of privileged 2- and 3-functionalized indoles via the Fischer indole synthesis, cycloaddition reaction, C–H activation reaction, and coupling reactions. Polycyclic derivatives of indole are also listed including triptamine-based pharmaceutical 5-HT1D agonist L 775,606. Some important mechanism studies are described in details in this review. The review covers literature for the last 20 years.

A simple, economical and one-pot protocol is developed for construction of multiple carbon-carbon bonds having C(sp2)-C(sp2) and C(sp2)-C(sp) hybridization, as these intriguing molecular architectures embrace significant optoelectronic and medicinal properties. To this end, a sequencial reaction is devised that allows one-pot three-component reaction of hydroxy benzaldehydes (C6-C1 unit), halo-phenylacetic acid (C6-C2 unit) and arylacetylenes (C6-C3 unit) resulting in the formation of highly π-conjugated complex arylethenyl-arylethynyl-arenes (C6-C2-C6-C2-C6 unit) bearing hydroxy group via sequential Perkin condensation/ decarboxylation-Sonogashira coupling reaction in poly(ethylene glycol) under microwave irradiation. The process avoids protection-deprotection manipulations, generates CO2 and H2O as by-products and has been successfully extended for the efficient construction of a wide series of novel aliphatic/ alicyclic/(hetero)aromatic arylethenyl-arylethynyl-arene with pendant hydroxy functionality which could allow further chemical modification to achieve desired biological and physical properties.

In this work, a new strategy to synthesize 3-sulfenyl/selenyl indole is reported wherein LC-MS reveals a novel insight into synergistic cooperative effect of NaBH4-I2 which allows cascade C-N and C-S/C-Se bond formations via reduction-nucleophilic cyclization-chalcogenylation, three steps in one-pot, towards regioselective synthesis of diverse 3-chalcogenyl indoles including 5-bromo-3-[(3,4,5-trimetoxyphenyl)thio]-1H-indole, a known lead anticancer compound, directly from 2-amino-phenacylchlorides and thiophenols or disulfides/diselenides in aqueous dioxane under metal-free condition.

Bifunctionalized indoles are an important class of biologically active heterocyclic compounds and potential drug candidates. Because of the lack of efficient synthetic methods, one pot cascade synthesis of these compounds is rare and remains a challenge. To expand this field, we herein disclose a step-economical and temperature tunable strategy wherein the synergistic effect between [hmim]Br-ArSO

Protecting-group-free synthesis of hydroxylated styryl–cinnamate hybrids (C6–C2–C6–C3 unit), inspired by the natural product salvianolic acid F, was achieved by a step-economical route involving sequential double C–C bond formation in one pot. The method involved multiple reactions (Perkin condensation/decarboxylation–Heck cross-coupling reactions) by using simple precursors (i.e., hydroxylated benzaldehyde, arylacetic acid, and acrylic acid derivatives) in one pot and yielded the desired unnatural small hybrid molecules in varying yields of 35–65 % with E selectivity under microwave irradiation, whereas the reported conventional route for the synthesis of salvianolic acid F itself requires six steps with an overall yield of 10.0 % in addition to tedious separation of E/Z isomers that arise from a Wittig reaction. Apart from an economical synthesis and product diversity, we herein report the potential of some hybrid molecules with the catechol core to selectively inhibit glioma cells. The intrinsic mode of action of our lead molecule, involving caspase 6 and the quinonemethide pathway, is also reported on the basis of 1H NMR spectroscopy guided metabolomic profiling. We emphatically demonstrate the role of our hybrid molecules, analogues of salvianolic acid F, in forcing glioma cells towards apoptosis by specifically perturbing the concentration of glutathione along with that of caspase 6.

The synergistic combination of two catalysts is an emerging strategy towards the formation of unprecedented complex molecules, and herein bovine serum albumin (BSA) and the neutral ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) are used together for the first time towards multiple C−C and C−S bond-formation reactions in one pot under metal-free, acid-free, and base-free conditions by merging two classical named reactions, that is, aldol condensation (AC) and thia-Michael addition (TMA) for the cascade chemoselective generation of β-aryl-β-sulfido carbonyl compounds from aliphatic ketones, aromatic aldehydes, and thiols. NMR spectroscopy and DFT calculations studies provided insight into the synergism, progress, and mechanism of the reaction, and control experiments highlighted that the single catalysts (BSA or IL) alone did not allow even the first AC step to proceed. Moreover this synergistic BSA–[bmim]Br catalytic system offers the step-economical synthesis of the anticoagulant warfarin through sequential aldol–Michael addition reactions and potent pyridine analogues through a Knoevenagel–Michael route. Besides, the recyclability of the catalytic system (up to 5 times) with the generation of water as a byproduct makes our one-pot protocol more economically efficient and synthetically attractive than traditional methods.

Cooperative cascade catalysis by bovine serum albumin (BSA)-iodine allows for the first time the performance of C(sp(2))-H sulfenylation of indole from readily available thiophenol (-SH bond) via in situ generation/cleavage of disulfide (S-S bond) in air under aqueous conditions, whereas BSA or I2 individually do not permit this two step sequence to occur in the same pot towards C-S bond formation. This green cooperative protocol is extendable to sulfenylation of hydroxyaryls (i.e. 2-naphthol or 4-hydroxycoumarin) with diverse thiols (aryl/heteroaryl) without using any toxic metal catalysts, bases or oxidants, thus rendering the process environmentally and economically reliable. Further, the gram scale synthesis of a COX-2 inhibitor (3-(pyridin-2-ylthio)-1H-indole), regioselectivity and recyclability (up to four cycles) are the additional merits of this cooperative cascade bio-chemocatalytic (BSA-I2) protocol. Moreover, HPLC and ESI-MS provide powerful insights into the mechanistic aspects of the above cascade sulfenylation reaction.

The first systematic evaluation of the antiplasmodial activity of the hydroxystilbene family of natural products and di/tristyrylbenzenes is described. A library of 27 diversely substituted hydroxy stilbenoids was rapidly synthesized using modified Knoevenagel–Perkin-decarboxylation–Heck sequences from readily available starting materials (i.e. hydroxybenzaldehyde–phenylacetic acid–arylhalide). These compounds were evaluated for in vitro antiplasmodial activity against three different strains of Plasmodium falciparum. Notably, 4,4′4′′-((1E,1′E,1′′E)-benzene-1,3,5-triyltris(ethene-2,1-diyl))tris(2,6-dimethoxyphenol) (27), an octupolar stilbenoid, showed IC50 (μM) values of 0.6, 0.5 and 1.36 while a distyrylbenzene (11) showed IC50 values of 0.9, 2.0 and 2.7 against 3D7 (chloroquine sensitive), Dd2 and Indo (chloroquine resistant) strains of Plasmodium falciparum respectively. Moreover, 27 and 11, which exhibited selectivity indices of 40 and >111 were also found to be nontoxic to the HeLa cell line. Microscopic studies revealed that the rings and trophozoites obtained from the 27 and 11 (an octupolar tristyrylbenzene and distyrylbenzene respectively) treated cultures were growth inhibited and morphologically deformed. These cultures also showed DNA fragmentation and loss of mitochondrial membrane potential (ΔΨm), suggestive of apoptotic death of the parasite. Together, these studies introduce di/tristyrylbenzenes as a new class of antimalarial agents.

The inherent affinity of natural compounds for biological receptors has been comprehensively exploited with great success for the development of many drugs, including antimalarials. Here the natural flavoring compound vanillin has been used as an economical precursor for the synthesis of a series of novel bischalcones whose in vitro antiplasmodial activities have been evaluated against erythrocytic stages of Plasmodium falciparum. Bischalcones 9, 11 and 13 showed promising antiplasmodial activity {Chloroquine (CQ) sensitive Pf3D7 IC50 (μM): 2.0, 1.5 and 2.5 respectively}but only 13 displayed potent activities also against CQ resistant PfDd2 and PfIndo strains exhibiting resistance indices of 1.4 and 1.5 respectively. IC90 (8 μM) of 13 showed killing activity against ring, trophozoite and schizont stages. Further, 13 initiated the cascade of reactions that culminates in programmed cell death of parasites including translocation of phosphatidylserine from inner to outer membrane leaflet, loss of mitochondrial membrane potential, activation of caspase like enzyme, DNA fragmentation and chromatin condensation. The combinations of 13 + Artemisinin (ART) exhibited strong synergy (ΣFIC50:0.46 to 0.58) while 13 + CQ exhibited mild synergy (ΣFIC50: 0.7 to 0.98) to mild antagonism (ΣFIC50: 1.08 to 1.23) against PfIndo. In contrast, both combinations showed marked antagonism against Pf3D7(ΣFIC50: 1.33 to 3.34). These features of apoptosis and strong synergy with Artemisinin suggest that bischalcones possess promising antimalarial drug-like properties and may also act as a good partner drugs for artemisinin based combination therapies (ACTs) against Chloroquine resistant P. falciparum.

Bovine serum albumin (BSA) has been explored for aerobic oxidative coupling of thiols (aromatic, heterocyclic as well as aliphatic) “on water” towards formation of disulphides (S S) without using any metal/non-metal complexes, bases and additives, which renders the process environmentally benign and economically attractive with good recyclability (up to four cycles). The developed green protocol was further extended for synthesis of diallyldisulphide (DADS), an important constituent of natural occurring allicin. Among various synthesized disulphides, bis(2-aminophenyl)disulphide, obtained by oxidative coupling of 2-aminothiophenol in BSA, was further utilized for condensation with benzaldehyde in the same pot thus enabling easy access to bioactive dithiobis(phenylene)bis(benzyldeneimine). This is the first example of BSA catalysed sequential (oxidation/condensation) reaction where one S S and two C N bonds are formed solely “on water.”

Multicomponent reactions are compelling strategies for generating a chemically diverse set of multifunctionalized heterocyclic motifs with high atom economy, rendering the transformations green. These strategies can further become more prolific if catalyst recyclability, compatibility and exploration of precise mechanistic pathways are considered. To this end, an inexpensive and recyclable glycine nitrate (GlyNO3) ionic liquid has been efficiently employed to obtain diversely substituted symmetrical and unsymmetrical 1,4-dihydropyridines with up to 93% yields via three and four components, respectively. The catalyst recyclability and compatibility to obtain both symmetrical and unsymmetrical 1,4 DHPs under identical reaction conditions are added benefits to its practical utility. Furthermore, progress of the reaction was monitored by Q-TOF, direct infusion electrospray ionization mass spectrometry (ESI-MS), and key cationic intermediates involved in the reaction have been further identified by a tandem MS experiment (Q-TOF, ESI-MS/MS), which served as the proof of concept to the mechanistic model. This is the first report which revealed that the Hantzsch reaction predominantly follows the diketone pathway among four competing reaction pathways.

A green methodology utilizing a natural supplement such as L-arginine in conjunction with water and oxygen led to oxidative coupling of thiols into disulfides (S–S bond) whereas thiol–yne coupling to access vinyl sulfides (C–S bond) was facilitated in a nitrogen atmosphere. The tunable protocol offers several advantages such as low catalyst loading, high yields, clean reaction, no over-oxidation of the S–S bond besides being metal/base/waste-free. The synthesis of ubiquitous cystine and glutathione disulfide in the same catalytic system is an added advantage and the catalytic system has been recycled up to seven times.

Purpose – The aims of the article are to not only review existing competency models and offer a comprehensive performance-linked competency model towards sustaining competitive advantage, but also validate the proposed model in an Indian textile organisation. Design/methodology/approach – The article operationalises the term “competency” and intends to develop a comprehensive performance-linked competency model after analysing the existing models with respect to competitive advantage; and the model has been validated empirically in an Indian textile company using data envelopment analysis (DEA), cross-efficiency DEA, and rank order centroid (ROC) methods. Findings – It reveals that the comprehensive performance-linked competency model focuses on competency identification, competency scoring and aligning competency with other strategic HR functions in a three-phase systematic method which will subsequently help the organisation to sustain in the competition. It has further been shown how using DEA, cross-e...

A series of cinnamyl compounds were synthesized from abundantly available methoxylated phenylpropenes and evaluated for their antimicrobial activity by the broth microdilution method against fourteen opportunistic bacterial and fungal human pathogens. Structure–activity relationship studies indicated that methylenedioxy cinnamaldehyde exhibited promising broad-spectrum activity against the tested microorganisms and hence was used as a lead structure to synthesize novel Schiff bases/heterocyclic compounds (23–33) under microwave irradiation. Out of these, thiazole-based Schiff bases have shown promising antibacterial activity against B. subtilis (26; MIC 0.12 mM), M. luteus (27; MIC 0.20 mM), and S. aureus (27; MIC 0.20 mM). Also, the compounds 23–33 were investigated for in vitro antioxidant activity using DPPH• assay where compound 28 showed a maximum of 80.71 % inhibition.

The objective of this paper is to develop an understanding of the diseases related with gallbladder, liver, and biliary tract. The study focuses on human biliary system that is how bile flows in the human body. This can be done by developing an understanding of gallbladder and bile flowing in the body and related organs very briefly. Gallstone is an important disease of gallbladder and is closely related to pressure drop. A small model for the human biliary system is also analyzed in this study. The cylindrical model of gallbladder and ducts in contraction and extension phase is used for the study. The amount of substances present in the organ varies in these cases. With the help of this study it is concluded that the flux decreases on increasing the radius and length of the cylinder. It is observed that the behavior of flow of bile in gallbladder is similar to the flow of bile in the ducts. Index Terms — Biological system modeling, Differential equations, Human biliary system, Disease

The selective oxidative coupling of thiols has been studied in several imidazolium-based ionic liquids in the absence of any base/metal catalysts. Disulfides were obtained from the corresponding thiols in good to excellent yields in 1-hexyl-3-methylimidazolium bromide ([hmim]Br). Furthermore, a 1H NMR-based mechanistic study of the S–S bond formation demonstrated the cooperative role of halide anion and imidazolium cation of [hmim]Br as an “ambiphile” – a character found to be imperative for the efficient syntheses of disulfides. The developed methodology is simple, selective and green that utilises molecular oxygen as an oxidant and produces water as the only by-product.

The human behavior is a combination of several feelings. There are two cases whether a person likes other individual or not. The liking of an individual leads to love and finally happiness. The feelings of love may be in different forms but here considered to be partners' love. There are three aspects of love for the partner: forgetting process (oblivion), the pleasure of being loved (return), and the reaction to the appeal of the partner (instinct). Along with that the appeals and the personalities of the two individuals do not vary in time. This model proves that if the geometric mean reactive-ness to love is smaller than the geometric mean forgetting coefficient and the system is asymptotically stable if the ratio of appeals is greater than the reciprocal of ratio of mutual intensiveness coefficient.

Rheum emodi is a storehouse of a large number of anthraquinone derivatives which are known for a large number of biological activities of significant potency. In this work, a study on the interactions between anthraquinone derivatives based natural dye isolated from R. emodi and different proteins has been reported for the first time, revealing the use of dye as an extrinsic probe to determine the stability of these proteins alone and in the presence of additives. The stability parameters have been evaluated as a change in the fluorescence intensity of the dye as a function of temperature due to the differential interaction of the dye with various conformations of a protein. Also, the effect of the change in polarity of the solvent on the fluorescence emission spectra of dye was studied where high quantum yield was observed in alcohol as compared to water. The RP-HPLC characterization of the dye revealed the presence of anthraquinones glycosides as main compounds in it. Thus, natural dyes may be used as biosensors to follow the conformational changes in proteins.

All in one: a tandem strategy has been developed wherein secondary aryl alcohols are directly coupled with aryl halides to provide stilbenoids through a dehydrative Heck sequence in the ionic liquid [hmim]Br, and with water as a by-product under microwave irradiation. Classical methods do not permit this sequence to proceed in one pot, and some methods require multiple steps. hmim=1-n-hexyl-3-methylimidazolium.

Novel stilbene-chalcone (S-C) hybrids were synthesized via a sequential Claisen-Schmidt-Knoevenagel-Heck approach and evaluated for antiplasmodial activity in in vitro red cell culture using SYBR Green I assay. The most potent hybrid (11) showed IC(50) of 2.2, 1.4, and 6.4 μM against 3D7 (chloroquine sensitive), Indo, and Dd2 (chloroquine resistant) strains of Plasmodium falciparum, respectively. Interestingly, the respective individual stilbene (IC(50)100 μM), chalcone (IC(50) = 11.5 μM), or an equimolar mixture of stilbene and chalcone (IC(50) = 32.5 μM) were less potent than 11. Studies done using specific stage enriched cultures and parasite in continuous culture indicate that 11 and 18 spare the schizont but block the progression of the parasite life cycle at the ring or the trophozoite stages. Further, 11 and 18 caused chromatin condensation, DNA fragmentation, and loss of mitochondrial membrane potential in Plasmodium falciparum, thereby suggesting their ability to cause apoptosis in malaria parasite.

During studies on exploiting the catalytic promiscuity of crude porcine pancreas lipase (PPL) in ionic liquid for C=C bond formations, bovine serum albumin (BSA) was found to be competing for these reactions. After a detailed investigation, we establish that these transformations are possible by unspecific protein catalysis rather than catalytic promiscuity of "PPL" - a first insight into the role of protein impurities in crude enzyme. Thus, a novel and highly efficient, environmentally friendly approach involving synergistic catalysis by bovine serum albumin-1-butyl-3-methylimidazolium bromide (BSA-[bmim]Br) has been developed for the synthesis of (E)-α,β-unsaturated compounds including a one-pot cascade synthesis of cinnamic acids and coumarins via aldol, Knoevenagel and Knoevenagel-Doebner condensations.

A series of chalcones (A–CH=CH–CO–B) were synthesized under microwave irradiation, and for the first time their pesticidal activity against diamondback moth (Plutella xylostella) was evaluated to identify the promising lead structures. The structure–activity relationship (SAR) analysis revealed that electron-withdrawing substituents on ring A of chalcone provided good pesticidal agents, whereas, ring B can bear either electron-withdrawing or electron-releasing substituents. Moreover, compound 22 having para-Cl substitution on ring A as well on ring B showed maximum activity with LC50 value of 170.24 μg mL−1.

Pseudomonas mandelii KJLPB5 is reported for the oxidation of aryl alcohols in ionic liquid [hmim]Br (1-hexyl-3-methyl imidazolium bromide) with H2O2. With a slight alteration of reaction conditions, the developed protocol leads either to (i) chemoselective oxidation of 2° aryl alcohols over 1° and aliphatic counterparts or (ii) direct one pot-two step sequential conversion of 2° aryl alcohols into corresponding one or two carbons shorter aryl aldehydes through oxidative cleavage pathway, thus providing a new facet to metal-free oxidations. The key operational parameters such as substrate concentration, incubation temperature, incubation time, ionic liquid type and ionic liquid concentration are also optimized.

H(2)O(2) mediated oxidation of alcohols in ionic liquid is revisited, wherein, ionic liquids under the influence of microwave irradiation have been found to facilitate activation of H(2)O(2) without any metal catalyst in aqueous condition. The method utilizes a neutral ionic liquid [hmim]Br both as catalyst and solvent for efficient and chemoselective oxidation of benzyl alcohol derivatives on aromatic (β, γ) alcohols, cyclic and aliphatic analogues, which can be a useful synthetic approach in total synthesis of complex organic compounds/natural products. Moreover, an unexpected oxidation of 9-anthracenyl propanol, a polyaromatic benzyl alcohol, resulting in the formation of 9,10-anthraquinone by the loss of propyl side chain was observed. Plausible mechanism and further exploration of this method on various other related substrates are discussed in detail.

A new approach has been developed for a one-pot and selective oxidative cleavage of aryl- and 1,2-diarylalkenes leading to one-carbon shorter aryl ketones; thereby, providing a complementary approach to classical ozonolysis. The methodology was applicable to diverse aromatic and polyaromaticarylalkenes bearing electron-donating or -withdrawing groups on the aromatic ring. The protocol also provided a useful one-pot oxidative cleavage–condensation sequence, which could potentially have important applications in natural product total synthesis.

This paper presents quantification of five anthraquinone derivatives (emodin glycoside, chrysophanol glycoside, emodin, chrysophanol and physcion) in rhizomes of hardened micro-propagated Rheum emodi plants using high-performance liquid chromatography (HPLC). Aseptic shoot cultures were raised using rhizome buds. Shoot multiplication occurred in both agar gelled and liquid Murashige and Skoog (MS) medium supplemented with 10.0 microM 6-benzylaminopurine (BAP) and 5.0 microM indole-3-butyric acid (IBA). Rooted plantlets obtained on plant growth regulator (PGR)-free medium were transferred to soil with 92% survival. HPLC analysis revealed the presence of five anthraquinone derivatives: emodin glycoside, chrysophanol glycoside, emodin, chrysophanol and physcion in rhizomes of tissue culture-raised plants. Only emodin glycoside (1) and chrysophanol glycoside (2) were present in 6-month-old hardened tissue cultured plants. In addition, the other three derivatives (emodin (3), chrysophanol (4) and physcion (5)) were also detected after 9 months.

A rapid and sensitive reverse phase high-performance thin-layer chromatographic (RP-HPTLC) method has been developed for the simultaneous determination of four bioactive phenolics, viz. epicatechin ( 1 ), syringic acid ( 2 ), quercetin-3- O -galactoside ( 3 ) and quercitrin ( 4 ) in the leaves of Rhododendron arboreum , Rhododendron campanulatum and Rhododendron anthopogon . HPTLC was performed on pre-coated RP-18 F 254S TLC plates. For achieving good separation, the mobile phase of methanol–5% formic acid in water, 50:50 (v/v) was used and densitometric determination of compounds was carried out at 290 nm in reflection/absorption mode. The method was validated in terms of linearity, precision, accuracy, and sensitivity. The calibration curves were linear in the range of 200–1200 ng for compounds 1 , 3 and 4 and 400–2400 ng for compound 2 . Lower limits of detection obtained for compounds 1 – 4 were 20, 40, 25 and 25 ng respectively, while the limit of quantification obtained were 50, 115, 75 and 70 ng respectively. The method was found to be reproducible and convenient for quantitative analysis of these compounds in Rhododendron species.

In the present study, microwave-assisted extraction was compared with conventional approaches for the efficient extraction of juglone and other phenolics from Juglans regia bark. The effect of different solvents was also studied and ethyl acetate was found to be a better solvent in terms of juglone yield and stability. Further, a simple and fast RP-HPLC method was developed and validated for the determination of juglone and other bioactive phenolics like gallic acid, caffeic acid, quercetin, myricetin, and quercitrin in these extracts. In addition, the extracts were tested for antimicrobial activity against 16 microorganisms where all the extracts showed broad spectrum activity.

Ionic liquids have been found to provide a new platform for metal- and quinoline-free decarboxylation of various N-heteroaryl and aryl carboxylic acids under microwave irradiation in aqueous condition. The method was found to possess a wide substrate scope towards the synthesis of various pharmacologically and industrially important aromatic compounds including indoles, styrenes, stilbenes, and nitro- or hydroxyarene derivatives. The decarboxylation of indole and alpha-phenylcinnamic acids proceeded well without addition of any catalyst in neat 1-hexyl-3-methylimidazolium bromide ([hmim]Br) and 1-methylimidazolium p-toluenesulfonic acid ([Hmim]PTSA), respectively, while addition of a mild base like aqueous sodium hydrogen carbonate (NaHCO(3)) to [hmim]Br further improved the decarboxylation of hydroxylated cinnamic and aromatic acid substrates. The developed methodology not only precludes the usage of toxic metal/quinoline and harsh organic bases but also offers several inherent benefits like recyclability of reagent system, reduction in waste and hazards, short reaction time besides ease of product recovery.

A mild and efficient, ionic-liquid-assisted, green protocol for the dehydration of benzyl alcohols into the corresponding (E)-arylalkenes under microwave irradiation has been developed. The method utilizes a neutral and recyclable ionic liquid (1-hexyl-3-methylimidazolium bromide) as a reagent and solvent to cleanly provide a wide range of olefins withoutthe need of harsh and expensive Bronsted/Lewis acids. The method was extended to the efficient conversion of acetylated/ benzoylated derivatives of benzyl alcohol into their corresponding (E)-arylalkenes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)