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A new reagent, 9-fluorenylmethoxy-carbonyl- N -hydroxy-3-azaspiro[5,5]undecane-2,4-dione ester (Fmoc-OASUD) for the preparation of Fmoc-amino acids is described. The Fmoc-OASUD reacts with amino acids at room temperature in the presence of a base and gives Fmoc-amino acids in high yields and purity. The Fmoc-amino acids prepared using Fmoc-OASUD are free from impurities due to Lossen rearrangement, which are generally present when Fmoc-OSu is used. This is mainly because of the higher stability of Fmoc-OASUD compared to Fmoc-OSu.

A typical three component reaction strategy towards the synthesis of 5-arylidenethiazolidinone compounds from thiazolidine-2,4-dione, piperidine, and appropriate aldehydes is described.

Carbocyclic nucleosides are considered as nucleoside mimetic having high therapeutic potentials, however diverse exploration is still limited due to their synthetic difficulties. The major challenges are associated with the preparation of new base and carbocyclic sugar key intermediates. The modified base may provide conformational advantage to achieve better nucleoside mimetics and may also help in increasing the drug-like properties. In this manuscript, we report the use of acetamidine hydrochloride to synthesize 6-methyl-4-amino-pyrazolo[3,4-d]pyrimidine base and regioselective synthesis of six new carbocyclic nucleosides (6a-f) for antiviral evaluation. Theoretical investigations were carried out on the basis of thermodynamic and kinetic stability using MM based energy optimizations and QM based transition state search for the significant regioselectivity, which was further experimentally analyzed by NOE and UV spectroscopy.

The reactions of N-aryl-3-hydroxyisoindolinones and alkyl aryl ketones under Lewis acid-catalyzed anhydrous conditions afforded the corresponding substituted isoindolinones in good to excellent yields.

A metal-free, one-pot, iodine-mediated, microwave-assisted cyclization of 1-(1′-arylvinyl)-2-naphthols (ortho-vinylnaphthols) into 1-arylnaphthofurans is developed. The 1-arylnaphthofurans are isolated in good to excellent yields (65–90%) using two equivalents of iodine in acetonitrile. The reactions proceed via the formation of 1-(2-iodo-1-phenylvinyl)naphthalen-2-ols as intermediates. Overall, the protocol is convenient as the reactions occur smoothly without the requirement of a transition-metal catalyst.

The synthesis of novel non-symmetric Buchwald-type biaryl-substituted phosphine ligands is developed and their efficiency as catalysts for C—N coupling reactions of aryl halides is demonstrated.

The paper describes the results of a new four-component synthesis of pyranopyrazole heterocycles by solvent-free one-pot grinding of malononitrile, hydrazine, ethyl acetoacetate, and various aldehydes in the presence of a base. The reaction proceeded smoothly at room temperature with good yields in very short reaction time. The synthesised compounds were evaluated for their in vitro antibacterial activity against three different bacterial and three different fungal strains. The highlight of this work is that the synthesis was activity-driven. The brief SAR correlation found that the tested compounds showed better activity against fungal strains.

Palladium catalyzed cross-coupling with aryl chlorides has always been a challenge and does not take place without the assistance of bulky phosphine ligands, NHCs or other additives. In this work, we present an unprecedented phosphine-free coupling of cheap and less reactive substrates like aryl chlorides with 1-(bromoethyl)benzene as a nucleophilic coupling partner at low Pd concentrations, under microwave conditions to access highly regio- and stereospecific trans-stilbene derivatives. The reaction is believed to proceed via a Pd–carbene intermediate generated in situ under MW conditions from 1-(bromoethyl)benzene. Another key requirement in the reaction is the presence of styrene; as in its absence, Pd catalysed coupling of halogenated ethyl benzene with chloroarenes does not take place at all. DFT studies have also been carried out to obtain a thermodynamic insight into the proposed mechanism.

A simple and efficient synthesis of Hagen's gland lactones was achieved using a sequential α-aminoxylation/oxa-Michael approach in a highly diastereoselective manner with assignment of relative configurations. This method was found to be applicable to the synthesis of various other isomers of Hagen's gland lactones.

Various cyclization precursors are prepared from indoline-2-thiones and selected unsaturated alcohols.

The reaction between variously substituted aryl or alkyl hydrazines and formamide provides the title compounds in moderate to good yields.

The title compounds (III) are obtained by a modified Pictet-Spengler method without the aid of any prefunctionalization.

D-glucosamine is found to be an efficient green replacement for phosphine ligands in the palladium-catalyzed Heck coupling of aryl and heteroaryl halides.

In nature, the commonly occurring reactive metal oxides of titanium, chromium, aluminium, and vanadium often chemically combine with the transition metal oxides such as iron oxides and form complex minerals. Physico-chemical separation of transition metal oxides from the remaining reactive metal oxides is therefore an important step in the purification of reactive oxide constituents. Each purification step has quite a high energy requirement at present. Current practice in industry yields sulphate and neutralized chloride waste from titanium dioxide enrichment, red mud from bauxite refining, slag and leach residues from vanadium extraction and chromite ore process residue (COPR) from chromate processes. In this review article, a novel alkali-based oxidative roasting and aqueous leaching for the extraction of mineral oxides is explained in the context of the original work of Le Chatelier in 1850, which was unsuccessful in the industrialization of bauxite processing for alumina extraction. However, much later in the 19th century the alkali-based oxidative mineral roasting was successfully developed for industrial scale manufacturing of chromate chemicals, which yields COPR. The crystal chemistry of mineral oxides, namely alumina, titanium dioxide, and chromium oxide in naturally occurring minerals is briefly reviewed in the context of chemical extraction, which is then developed as a model for developing thermodynamic chemical equilibrium principles for analyzing the physical separation and enrichment of such reactive metal oxides by forming water-soluble and water-insoluble alkali complexes. The involvement of the alkali roasting chemistry of non-magnetic titaniferous mineral waste is also reported in the initial separation of rare-earth oxide mixtures for subsequent separation of individual oxides. The paper concludes with a generic approach to process chemistry which minimizes waste generation and therefore helps in reducing the overall process and energy costs. Examples of recovering alkali from high pH solution using carbon dioxide are also demonstrated.

A facile synthesis of indole annulated 2H-thiopyran-2-ones has been developed by condensation of indoline-2-thiones with acetoacetic esters in the presence of borontrifluoride etherate (BF3 etherate) using microwave irradiation. This one-step operationally simple methodology leads to thiopyrano[2,3-b]indol-2-ones in good yields.

Title compounds (III), (V), (VII), and (IX) are prepared from starting indolecarbaldehydes (I) and (VIII) (accessible via Vilsmeier-Haack formylation of respective alkylthioindoles) by ethylenediamine-diacetate-mediated reaction with indoline-2-thiones (II), (IV), and (VI).

A simple and highly efficient approach to an enantioenriched 2,6-disubstituted piperidin-3-ol skeleton is developed from an aldehyde as a starting material by using organocatalytic and asymmetric dihydroxylation as the key steps. Its application to the total synthesis of (–)-deoxoprosopinine and (+)-deoxoprosophylline is also reported.

An unique one-pot, catalyst-free tandem reduction of oxo and ene/yne functionalities of substituted isatins is disclosed for the synthesis of oxindole derivatives.

BaNb2O6:Eu3+ phosphors (1, 4, 10, 12, 14, 16 mol% Eu) are prepared by calcination of stoichiometric amounts of BaCO3, Nb2O5, and Eu2O3 in air (1.

Electrophilic iodocyclization of 2-(aminobutyne)-anilines (I) affords selectively pyrrole derivatives (II) rather than alternative indoles.

A Cu-catalyzed tandem approach for the synthesis of indolo- and pyrrolonaphthyridines via regioselective addition of indoles or pyrrole to 3-bromo-2-ethynylpyridines (II) followed by intramolecular cyclization is presented.

An operationally simple approach for the stereoselective tandem synthesis of novel thiazolo fused naphthyridines 5a–o and thienopyridines 8a–e by the reaction of o-alkynylaldehydes with L-cystine methyl ester hydrochloride via Au(III)-catalyzed regioselective 6-endo-dig ring closure under mild reaction conditions is described. It is noteworthy that alkynes bearing an alkyl and a strong electron-withdrawing nitro group successfully afforded the desired products in good yields.

An efficient tandem approach for the regio- and stereoselective synthesis of oxazolo-fused naphthyridines 3a–g, 3i–l and isoquinolines 3h, 3m via the reaction of o-alkynylaldehydes 1a–i with chiral amino alcohols 2a–c under mild reaction conditions is described. The stereochemistry and structures of the products were assigned via NOESY and X-ray crystallographic studies.

New compounds (IVb) and (IVc) show good antimicrobial activities against all the tested bacterial and fungal pathogens, however, their activities are not on par with the standard antimicrobial agents.

An efficient tandem C—N, C—O bond formation reaction is developed for the synthesis of title compounds (III), (VI) and related homologues (V).

The presence of electron donating alkyl groups in starting material (I) is key to the success of the reaction.

Novel triazole-fused heterocycles are regioselectively obtained via a ligand-free copper-catalyzed tandem azide—alkyne cycloaddition (CuAAC), Ullmann-type C—N coupling reaction and subsequent intramolecular C—C bond formation by C—H functionalization.

A new strategy is reported to synthesize the title compounds via a tandem Povarov reaction, dihydroquinoline oxidation, and imine reduction.

Triazolium based ionic liquids with carbohydrates at the 1- and 4-position are synthesized and utilized as ligands for the CuI-catalyzed amination of halobenzenes (I).

A large number of noncentric and centric organic and inorganic crystals exhibit intrinsic and extrinsic fracto-mechanoluminescence (ML) due to the electron bombardment and electron-trapping mechanisms, and only a few crystals show ML due to the chemically induced fracto-ML and other possible mechanisms. The charged surfaces produced during fracture of solids owing to piezoelectrification, defective-phase piezoelectrification, movement of charged dislocations, baro-diffusion of defects near the crack-tip, and many other processes may cause production of very high electric field near the charged surfaces. In the case of non-photoluminescent and non-cathodoluminescent materials, the high energy electrons may be emitted from the charged surfaces and the electron bombardment (EB) mechanism may excite the molecules of surrounding gases and subsequently the gas discharge ML may be produced. In photoluminescent and cathodoluminescent solids, the electron bombardment may cause cathodoluminescence. In certain photoluminescent crystals, the light of gas discharge may excite photoluminescence. In many solids, the free electrons produced at fracture may be captured in the traps and consequently the electron-trapping (ET) mechanism may give rise to the light emission. Few solids may exhibit chemiluminescence because of the chemical reactions at the newly created surfaces. Some solids may exhibit black body radiations because of the high temperature produced near the tip of the moving cracks. Infrared radiation may also be emitted during the fracture of certain crystals. In certain solids, the gas discharge fracto-ML and the photoluminescence excited by the gas discharge disappear when the solids are fractured inside liquids; however, in certain solids the solid state fracto-ML appears even inside the liquids if they are not based on the processes involving gas discharge. Overall, depending on the prevailing conditions the ML spectra consist of either the gas discharge spectra or solid state luminescence spectra or the combination of the both. The fracto-ML of SrAl 2 O 4 :Eu, europium tetrakis (dibenzoyl methide) triethyl ammonium, ditriphenylphosphine oxide manganese bromide, freshly grown impure saccharin, etc. is so intense that it can be seen in day light with naked eye. The understanding of the mechanism of fracto-ML may be useful in preparing suitable fracto-mechanoluminescent materials and it may be helpful in designing the fracto-ML based devices such as fracture sensor, impact sensor, damage sensor, safety management monitoring system, fuse system for army warheads, etc.

Unsymmetrical internal alkynes such as (X) or (XII) generate selectively a single isomers [cf.(XI) or (XIII)].

An efficient approach for the copper-catalyzed regioselective tandem synthesis of diversely substituted indolo[2,1-a]isoquinolines 11a–r, pyrrolo[2,1-a]isoquinolines 12a–d, and indolo-, pyrrolo[2,1-f][1,6]naphthyridines 14a–f via preferential addition of the heterocyclic amines onto the ortho-haloarylalkynes over N-arylation followed by intramolecular C-2 arylation is described. The scope of the developed chemistry was successfully extended for the direct synthesis of bisindolo-, pyrrolo[2,1-a]isoquinolines 15a–g, a regioisomer of the bisindolo[1,2-a]quinolines used as organic single-crystal field-effect transistor. Hydroxymethyl benzotriazole, which is an inexpensive and air stable compound, has been used as a ligand to carry out this one-step conversion of simple, readily available starting materials into an interesting class of heterocyclic compounds.

Surface functionalization of SBA-15 followed by its reaction with Cu(OAc)2 has been carried out to develop a new Cu-grafted functionalized mesoporous material, which catalyzes one-pot three component coupling of different aryl halides with thiourea and benzyl bromide in aqueous medium to produce aryl thioethers in very good yields (80–88%).