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An unprecedented approach for the synthesis of homo- and hetero-1,2,4-triaryl benzenes has been developed using a simple base-mediated reaction of either α-aryl cinnamyl alcohols or α,γ-di-aryl propanones. The salient feature of this strategy involves the sequential hydride transfer, regiospecific condensation, regiospecific dearylation, and aromatization under metal-free reaction conditions. The synthesis of unsymmetrically substituted triphenylenes by oxidative coupling of the synthesized 1,2,4-triaryl benzenes has also been demonstrated.

Mixed-metal molybdates are interesting host materials for ion-insertion electrodes due to their versatile crystal chemistry, which confers a highway for the conduction of electrons as well as ions. Silver decamolybdate in triclinic crystal structure (T-Ag6 Mo10 O33 ) consists of layers of MoO6 octahedra separated by arrays of silver ions that are able to store a high amount of charges.

Heterocyclic compounds play a major role in drug discovery processes as these are the common structural motif for 80% of the marketed drugs by US retail sales in 2014. Benzimidazole and its derivatives are regarded as important heterocyclic motifs that exhibit a wide range of pharmaceutical applications including anticancers, antihypertensives, antivirals, antifungals and anti-HIVs. In view of their wide ranging bioactivities, it is imperative to focus on the synthesis of heterocyclic molecules containing benzimidazole as one of the moieties. This review focuses on the application of solid supports for the synthesis of different classes of benzimidazole-based biheterocyclic molecules in the last decade. In this review paper, detailed synthetic steps involved for the synthesis of benzimidazole-based biheterocyclic molecules, are shown in the schemes. The synthesis covers linear, angular and fused benzimidazole-based biheterocyclic molecules by a combinatorial approach. In addition, in the introduction section we shed some light on the use of biheterocyclic molecules as current drugs and open a new avenue for the utilization of these biheterocyclic molecules for pharmaceutical applications.

Nanocelluloses, derived from the biopolymer cellulose, are a class of sustainable functional nanomaterials featuring exciting properties. They have been extensively researched as key components in the design of super capacitors, pH-responsive reversible flocculants, aerogels, sensors, pharmaceuticals, chiral materials and catalysts. This review will focus on the applications of nanocelluloses in catalysis. The first part illustrates their use as support, stabilizer and/or reducing agent in the synthesis of various metal nanoparticle. Subsequently, the applications of these metal-hybrid nanocellulose composites in catalysis are reviewed. Finally, catalysis involving nanocelluloses, without the use of metal nanoparticles, is reviewed.

A facile and efficient synthesis of novel oxo, thio and seleno hydantoin fused tetrahydroazepino [4,5-b]indoles was reported. A naturally occurring iboga class alkaloid inspired seven-membered azepino[4,5-b]indole ring was synthesized as a new scaffold through Pictet–Spengler reaction followed by skeletal rearrangement of the aziridine ring. To improve the efficiency of the synthetic route, the double bond of the rearranged olefinic product 5 was reduced and a privileged hydantoin moiety was constructed on the core system through urea formation using a variety of isocyanates, isothiocyanates and isoselenocyanates followed by intramolecular cyclization to incorporate elements of diversity. The regeneration of the double bond of intermediate 9 afforded hydantoin-fused tetrahydroazepino [4,5-b]indoles.

An efficient solid-phase benzoylation of phenols and alcohols was developed under microwave irradiation. A stoichiometric amount of benzoyl chloride was sufficient to carry out the reaction. This benzoylation features short reaction time, good yields, and easy workup procedures. Furthermore, the scope of the reaction was extended to prepare 3,5-dinitrobenzoyl derivatives of alcohols.

A Pd—poly(1,2-diaminobenzene) composite material with palladium nanoparticles with an average size of 3 nm are synthesized from 1,2-diaminobenzene (DAB) and K2PdCl4 and successfully used as a catalyst for Suzuki coupling reactions in the absence of any phosphine ligand.

Pd nanoparticles with cubic, cuboctahedral, and octahedral shapes are used to catalyze the Tsuji—Trost allylic amination reaction of aniline derivatives.

A polymer supported copper(I) composite has been synthesized using a one-step chemical synthesis route under ambient conditions. The resultant material serves as an effective catalyst for a 1,3-dipolar cycloaddition reaction between terminal alkynes and azides to synthesize 1,2,3-triazoles with excellent yields using a microwave irradiation technique in the absence of any solvent. The composite has also been found to be an effective catalyst for the multicomponent synthesis of 1,2,3-triazoles from organic halides, sodium azide and terminal alkynes under the identical conditions as mentioned above.

Described is an efficient stereocontrolled route into valuable, densely functionalized fluorinated phosphonates that takes advantage of (i) a Clostridial enzyme to set the absolute stereochemistry and (ii) a new [3,3]-sigmatropic rearrangement of the thiono-Claisen variety that is among the fastest sigmatropic rearrangements yet reported. Here, a pronounced rate enhancement is achieved by distal fluorination. This rearrangement is completely stereoretentive, parlaying the enzymatically established β-C–O stereochemistry in the substrate into the δ-C–S stereochemistry in the product. The final products are of interest to chemical biology, with a platform for Zn-aminopeptidase A inhibitors being constructed here. The enzyme, Clostridium acetobutylicum (CaADH), recently expressed by our group, reduces a spectrum of γ,δ-unsaturated β-keto-α,α-difluorophosphonate esters (93–99% ee; 10 examples). The resultant β-hydroxy-α,α-difluorophosphonates possess the “l”-stereochemistry, opposite to that previously observe...

Complete regioselectivity for formation of 1,4-triazoles is obtained using gold rhombic dodecahedra.

This new one-pot protocol furnishes the title compounds under solvent- and catalyst-free conditions with better yields and in shorter reaction times than a previously reported two-step reaction.

The reaction provides moderate to very good yield of the products at room temperature within few hours and tolerates various functional groups.

Malaria has emerged as a major health problem worldwide after the appearance of resistant strains of Plasmodium falciparum to the most of antimalarial drugs. The development of resistance by the parasite against first line as well as second line antimalarial drugs has drawn attention to develop new drugs to alleviate the disease burden. Therefore, there is a great need for new antimalarial drugs with improved attributes over older therapies. This review is primarily addressed to description of the recent advances in the synthesis of heterocyclic compound as antimalarial agents which can facilitate the development of more potent and effective antimalarial agents.

All newly synthesized compounds are screened for their antiinflammatory and antibacterial activities.

An inexpensive and rapid alternative method for the synthesis of structurally diversified polyfunctionalized quinolines of pharmaceutical interest is developed.

Recently, chemical cross coupling reactions have emerged as a powerful tool in the hands of synthetic organic chemist to synthesize complicated organic scaffolds like drugs, natural products, optical devices and industrially impor- tant materials. Stable N-Heterocyclic Carbene (NHC) acts as an important catalyst system in various cross coupling reac- tions. This review describes various strategies used for the synthesis of free and stable NHCs. Historical developments made in the propagation of the idea of free and stable carbene have also keenly been illustrated in the introduction of this

Polypyrrole stabilised palladium nanoparticles show good catalytic efficiency for the chemoselective transfer hydrogenation of α,β-unsaturated carbonyl compounds. The catalyst is very specific and selectively hydrogenates the olefins or acetylenes only, without affecting the carbonyl moiety, with an excellent yield of products for a wide range of substrates.

Copper(I) promoted Huigsen 1,3-dipolar cycloaddition of terminal alkyne with azide is utilized as an efficient protocol for the one-pot five-component synthesis of glycoside annulated dihydropyrimidinone derivatives with 1,2,3-triazol linkage accomplished by tert-butyl β-ketoester, arylaldehyde, urea, propargyl alcohol, and glycosyl azide through the combination of transesterification and Biginelli reaction in aqueous medium. This protocol provides an access to generate scaffolds with molecular diversity from readily available starting materials.

We report the highly facet-dependent catalytic activity of Cu2O nanocubes, octahedra, and rhombic dodecahedra for the multicomponent direct synthesis of 1,2,3-triazoles from the reaction of alkynes, organic halides, and NaN3. The catalytic activities of clean surfactant-removed Cu2O nanocrystals with the same total surface area were compared. Rhombic dodecahedral Cu2O nanocrystals bounded by {110} facets were much more catalytically active than Cu2O octahedra exposing {111} facets, whereas Cu2O nanocubes displayed the slowest catalytic activity. The superior catalytic activity of Cu2O rhombic dodecahedra is attributed to the fully exposed surface Cu atoms on the {110} facet. A large series of 1,4-disubstituted 1,2,3-triazoles have been synthesized in excellent yields with high regioselectivity under green conditions by using these rhombic dodecahedral Cu2O catalysts, including the synthesis of rufinamide, an antiepileptic drug, demonstrating the potential of these nanocrystals as promising heterogeneous catalysts for other important coupling reactions.

A simple and efficient transesterification process for the synthesis of β-ketoester derivatives is achieved by the reaction of methyl β-ketoester with higher alcohols under catalyst-free conditions.

We report here a method for the preparation of polymer hollow spheres in which 3-aminoquinoline (3-AQ) and palladium acetate were used as precursors. During the reaction 3-AQ was oxidized and formed poly(3-AQ). IR and Raman spectra provided information on the chemical structure of the polymer. The oxidation state of palladium was confirmed by X-ray photoelectron spectroscopic analysis. Transmission and scanning electron microscopy were used to determine the size and morphology of the polymer. The palladium–poly(3-AQ) supramolecular system was used as an effective catalyst for the Suzuki coupling reaction of aryl halides in the absence of a phosphine ligand. Copyright © 2013 John Wiley & Sons, Ltd.

In general aryl iodides and bromides can be applied with iodide leading to the products with higher yields.

Acetyl chloride is one of the most commonly available and cheap acylating agent but its high reactivity and concomitant instability in water precludes its use to carry out acetylation in aqueous medium. The present methodology illustrates the efficient acetylation of primary amines and amino acids in brine solution by means of acetyl chloride under weakly basic condition in the presence of sodium acetate and/or triethyl amine followed by trituration with aqueous saturated bicarbonate solution. This effort represents the first efficient use of this most reactive but cheap acetylating agent to acetylate amines in excellent yields in aqueous medium. This is a potentially useful green chemical transformation where reaction takes place in environment-friendly brine solution leading to easy work-up and isolation of the amide derivatives. Mechanistic rationale of this methodology is also important.

The search for efficient synthetic procedures for natural products, drugs, and materials with economical and ecological advantages is an important area of current interst in synthetic organic chemistry. We have made an attempt to summarize the progress made in this area since 2005. This article describes the syntheses of several natural products and drugs that employ multiple palladium-catalyzed processes in either a sequential or a domino fashion. 1 Introduction 2 Palladium-Mediated Synthesis of Alkaloids 2.1 Indole Alkaloids 2.2 Carbazole Alkaloids 2.3 Quinoline and Isoquinoline Alkaloids 2.4 Pyrrole and Pyridine Alkaloids 2.5 Pyrrolizidine and Indolizidine Alkaloids 2.6 Imidazole and Guanidine Alkaloids 2.7 Other Alkaloids 3 Palladium-Mediated Synthesis of Natural Products Containing a Sugar Moiety 4 Palladium-Mediated Synthesis of Marine Natural Products 5 Palladium-Mediated Synthesis of Amino Acids and Peptides 6 Palladium-Mediated Synthesis of Terpenoids 7 Miscellaneous Natural Products 8 Conclusion

A convenient method for the synthesis of 5- to 8-membered benzoheterocycles is achieved by 1,3-dipolar cycloaddition of o-iodophenyl-substituted azides with a variety of acetylenic substrates followed by cyclization of the resulting triazoles.

CaCl2 (20 mol %) dispersion in DMSO or aq HBr (10 mol %) is developed as an efficient and cost effective acid catalyst for the simple one-pot synthesis of 9-aryl-1,8-dioxooctahydroxanthene derivatives. Reaction of aromatic aldehyde (1 equiv) and dimedone (2 equiv) in the presence of CaCl2 (20 mol %) in CHCl3 at room temperature gave the open chain analogue of 1,8-dioxooctahydroxanthene. Similarly, aq HBr (10 mol %) in water at reflux temperature gave a high yield of 9-aryl-1,8-dioxooctahydroxanthene derivatives. The use of inexpensive, eco-friendly and readily available catalysts, easy work-up, and isolation of the products makes these procedures a convenient method for the synthesis of either of the products.

The special interest attached to the chemistry of metal carbonyls arises from several causes. While quite distinct from the metal carbonyls in the organometallic compounds, they differ in physical properties (e.g., their volatility) from all other compounds of the transition metals. Chemically, they constitute a group of compounds in which the formal valency of the metal atoms is zero, and in this respect (apart, perhaps, from the ammoniates of the alkali metals) they are comparable only with the recently discovered compounds. As a class, the carbonyls are reactive compounds, and a number of new types of inorganic compounds have been discovered. In the concepts for new products, performance, product safety, and product economy criteria are equally important. They are taken into account already when the raw material base for a new industrial product development is defined. Since the discovery of nickel carbonyl by Mond and Langer in 1888, the carbonyls of the iron group and of chromium, molybdenum and tungsten have found important technical applications, e.g., in the Mond nickel process, and for the preparation of the metals in a state of subdivision and of purity suitable for powder metallurgy, for catalysts, etc. The reaction mechanism of the processes developed for producing the carbonyls technically has only recently received its interpretations. Within the space of review it is necessary to limit discussion to a few topics. Particular stress has accordingly laid upon (a) the chemical bonding in metal carbonyls, (b) importance of IR and NMR spectroscopy in characterization of metal carbonyls, (c) substitution reactions of G-VIb metal carbonyls, (d) kinetics and mechanism of substitution reactions in metal carbonyls, (e) substituted complexes of G-VIb metal carbonyl, (f) chelate complexes of G-VIb metal carbonyls, (g) uses of G-VIb metal carbonyl complexes and (h) studies done on G-VIb metal carbonyls.

Treatment of aminoester substrates with aqueous NH3 at room temperature renders possible the access to a library of title compounds whose structure includes an amide and a guanidine functionality.

An efficient and operationally simple method for the dehydrogenation of 4-aryl-3,4-dihydropyrimidin-2(1H)-ones (DHPMs) has been developed using CAN/HCl.

The polystyrene-supported 2-isobutoxy-1-isobutoxycarbonyl-1,2-dihydroquinoline (PS-IIDQ) is found to be more efficient than IIDQ and polymer-supported carbodiimide.

The title compounds (III) are synthesized via click chemistry by Cu-catalyzed cycloaddition of various bisalkynes with azides.

NBS efficiently promotes the condensation of aldehydes with uracil derivative (I) in the presence of a catalytic amount of AIBN in a single step via a radical chain reaction.

The efficient process is extended to the structurally related naphthalene derivative (III).

A simple and scalable protocol is developed for the synthesis of amides (III) by condensation of carboxylic acids with CDI providing imidazole intermediates which react with various amines.

The method allows a ready preparation of the pharmaceutically relevant heterocycles in good to excellent yields and high purity.

A highly efficient and green protocol for monoacylation of symmetrical diamines and chemoselective acylation of primary amines of unsymmetrical diamines has been developed.

A palladium poly(aminophenol) composite is developed which shows excellent catalytic activity in Heck coupling reactions.

A novel synthesis of hydantoins with a variety of substituents is achieved by thermal cyclocondensation.

A general approach towards aminobenzimidazoles (V) is presented, using an ionic liquid support for more operational simplicity.