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We have described an efficient one-pot five component reaction of acetylacetone, aryl azides, aromatic aldehydes, isatin and l -proline using DBU as catalyst in PEG-400 at 80 °C for the construction of novel heterocyclic triazolyl spirocyclic oxindole derivatives. Structures of all synthesized novel compounds have been confirmed by spectral and X-ray studies. Crystal packing of compound 6i has also been reported. Green solvent, less reaction time, easy work up and high yields are the salient features of the present protocol. The same reaction has also been reported by stepwise reactions including a one-pot three component reaction.

A palladium-catalyzed tandem-cyclization of functionalized ynamides to afford a wide range of hetero-substituted benzosultams (1,2-benzothiazine 1,1-dioxides) has been achieved. Medicinally useful compounds like nortriptyline and eugenol could also be used as nucleophiles. Base has a significant effect in the cyclization process, depending on the nucleophile source used. DFT studies suggest that the reaction involves a [Pd(II)]–[Pd(0)]–[Pd(II)] cycle. Structures of key products were proven by X-ray crystallography.

A first highly enantioselective addition of naphthols and sesamol to indolylidene cyanoacetate derived from isatins was carried out in the presence of bi-functional quinine thiourea as organocatalyst. Under optimized reaction conditions the present catalytic system gave spiro-oxindole derivatives with excellent yield and enantioselectivity (up to 99%) at very low catalyst loading (2 mol%). The absolute configuration of 3i was determined by single X-ray crystallographic analysis to be the S isomer of the product. A catalytic cycle is proposed based on NMR, IR and kinetic studies.

Title compounds are synthesized via 1,3-dipolar cycloaddition reaction of Knoevenagel adducts (I), 1,3-thiazole-4-carboxylic acid (II) and acenaphthenequinone (III) in water and in the presence of sodium chloride.

CF3 substituted β-nitronitriles with an all-carbon quaternary stereogenic center have been synthesized via asymmetric cyanation reaction. In situ generated chiral TiIV salen complexes were used as catalysts for asymmetric addition of TMSCN to nitroolefins containing a trifluoromethylated prochiral center in the β-position, to afford the corresponding β-nitronitriles in excellent yield (up to 93%) with good enantioselectivity (up to 99%). This newly developed catalytic protocol led to the efficient synthesis of useful but challenging chiral α,α′-disubstituted β-amino acids.

An efficient La(OTf)3-catalyzed three-component reaction has been developed for the synthesis of highly substituted spiro[indolo-3,10′-indeno[1,2-b]quinolin]-2,4,11′-triones in polyethylene glycol (PEG-400) under conventional heating and ultrasonic irradiation. The most exciting feature of this methodology is its mechanism involving the unusual ring opening of an isatin moiety followed by recyclization. All the reactions resulted in good yield of products. The important features of this reaction are use of green solvent, good yields, less reaction times, and recyclability of the catalyst.

One-pot heterocyclic synthesis is an exciting research area as it can open routes for the development of otherwise complex transformations in organic synthesis. Heterocyclic compounds show wide spectrum of applications in medicinal chemistry, chemical biology, and materials science. These heterocycles can be generated very efficiently through highly economical and viable routes using one-pot synthesis. In particular, the metal-free one-pot synthetic protocols are highly fascinating due to several advantages for the industrial production of heterocyclic frameworks. This comprehensive review is devoted to the transition metal-free one-pot synthesis of nitrogen-containing heterocycles from the period 2010–2013.

Total synthesis of (±)-taiwaniaquinol F (1a) has been accomplished via an efficient Lewis acid-catalyzed Nazarov-type cyclization of aryldiallylcarbinols (±)-2e derived from safranal 7. The methodology works under mild conditions using only 2 mol % of metal triflate as catalyst to afford a previously unknown carbotricyclic core sharing an olefin functionality in excellent yield. The aforementioned methodology also offers enough flexibility to complete the total syntheses of various taiwaniaquinoids, including (±)-taiwaniaquinone H (1d), (±)-dichroanone (1e), (±)-5-epi-taiwaniaquinone G (ent-1h), and (±)-taiwaniaquinol B (1b).

A facile regio- and stereoselective synthesis of novel dispiroheterocyclic hybrids containing benzo[1,4]oxazine/benzo[1,4]thiazine and pyrrolidine/thiapyrrolizidine moieties via 1,3-dipolar cycloaddition reaction was carried out. The reaction has been carried out using 2,2,2-trifluoroethanol as a new alternative green solvent and catalyst for rapid access to construct a diversity-oriented library of regioselectivity dispiropyrrolidine/thiapyrrolizidines. Mild reaction conditions with excellent conversion, higher yields in shorter reaction times and the easy recyclability of 2,2,2-trifluoroethanol makes this protocol attractive, sustainable and environmentally benign.

A highly efficient decarboxylative synthesis of vinyl or alkynyl sulfones is achieved from cinnamic acids or propiolic acid derivatives and sulfonylhydrazides under mild reaction conditions.

Structurally diverse spiroheterocycles, spiroannulated with imidazothiazole and imidazothiadiazole, are obtained by an environmentally benign isocyanide based domino protocol involving the three-component reaction of benzothiazole (I)/thiadiazole (IX), isocyanides (II), and isatins (IV)/cyclic carbonyl compounds (V)/(VII).

Regioselective synthesis of functionalized dihydropyran derivatives by DABCO-catalyzed [2 + 4] cycloaddition of allenoates with enynals or enynones has been developed. Phosphine-catalyzed [3 + 2] cycloaddition of allenoates with enynals provides 1,1-alkyne (aldehyde)-substituted cyclopentenes wherein enynals act as electrophiles. These alkyne-tethered cyclopentenes upon [Au]/[Ag] catalysis lead to substituted benzofurans via 1,2-alkyl migration and dehydrogenation (aromatization). One-pot reaction of allenoates with enynals using sequential phosphine and gold catalysis is also reported. The cyclopentene obtained from the PPh3-catalyzed reaction of allenoate H2C═C═CH(COO-t-Bu) with enynal undergoes decarboxylation under the [Au]/[Ag] catalysis and forms a carboxylate-free benzofuran. The structures of key products are confirmed by single-crystal X-ray analysis.

An efficient method for the synthesis of the title compounds (V) is developed using a microwave-assisted Hinsberg heterocyclization using either montmorillonite or Yb(OTf)3 as catalysts.

Thioethers are prepared by cross—coupling of arylsulfonyl hydrazides and aryl boronic acids using a nickel catalyst.

11 Title compounds of type (IV) are prepared by a three-component one-pot reaction using NMP·H3PO4 as a catalyst.

Water soluble iron(III) porphyrins immobilized in imidazolium ionic liquids serve as an effective catalyst for the H2O2 mediated oxidation of guanidoximes to selectively give corresponding cyanamides in good yields. The use of ionic liquid with non-coordinating counter anion PF6 affords the product in high yield by facilitating the formation of anionic iron peroxo intermediate.

16 Tetracyclic compounds of type (III) are prepared and evaluated for their in vitro antibacterial activity.

The title compounds (III)/(VI) are obtained by CSA-catalyzed reaction of carboxylic acid hydrazides with different carboxylic acid chlorides.

Phosphotungstic acid supported on nanoparticles of Fe3O4—SiO2 is an efficient catalyst for the solvent-free hydrophosphonylation of aldehydes (I) and isatins (VIII) leading to corresponding α-hydroxyphosphonates (III) and (IX), respectively.

Thiazole is a valuable scaffold in the field of medicinal chemistry and has accounted to display a variety of biological activities. Thiazole and its derivatives have attracted continuing interest to design various novel CNS active agents. In the past few decades, thiazoles have been widely used to develop a variety of therapeutic agents against numerous CNS targets. Thiazole containing drug molecules are currently being used in treatment of various CNS disorders and a number of thiazole derivatives are also presently in clinical trials. A lot of research has been carried out on thiazole and their analogues, which has proved their efficacy to overcome several CNS disorders in rodent as well as primate models. The aim of present review is to highlights diverse CNS activities displayed by thiazole and their derivatives. SAR of this nucleus has also been well discussed. This review covers the recent updates present in literature and will surely provide a greater insight for the designing and development of potent thiazole based CNS active agents in future.

The method for the title synthesis needs no transition metal catalysts and proceeds in shorter reaction time.

12-Aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one derivatives were synthesized by a convenient and environmentally benign procedure involving multicomponent condensation reactions of substituted aromatic aldehydes with 2,7-dihydroxynaphthalene/2-naphthols/2,6-dihydroxynaphthlene and cyclic 1,3-dicarbonyl compounds in task specific acidic ionic liquid [NMP]H 2 PO 4 at 80 °C. This protocol has proved to be efficient in terms of good yields, operational simplicity, easy workup, recyclability of reaction medium/catalyst, and short reaction time.

A pre-synthesized stable complex of a novel bis-camphorsulfonyl urea derivative with two equivalents of NaBPh4 is successfully employed as catalyst for the asymmetric Michael addition of pyrrole or indole to give nitroolefins.

The title compounds (IV) (18 examples) are obtained via a multicomponent reaction in the presence of the task-specific ionic liquid [DBU][AcOH], which plays the dual role of both catalyst and reaction medium.

Pyrazole is a versatile lead compound to design potent bioactive molecules for drug discovery and development, particularly in cancer therapy. The aim of this review is to present the most recent deeds in the field of synthetic route made for functionalized pyrazole derivatives active against cell proliferation disease. The review article covers the synthesis of 1H-pyrazole, synthesis of N-substituted pyrazoles, synthesis of pyrazolopyrazoles, and synthesis of pyrazoles fused with a naturally occurring moiety. Some of these reported compounds have passed the preclinical or initial-phase clinical trials for their anticancer activity.

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties (catalytic activity). Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco-friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO 2 nanoparticles (TiO 2 NPs) were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4(1 H )-one synthesis. Synthesized compounds were confirmed using FT-IR, 1 H NMR, 13 C NMR and GC–MS analyses.

A practical and environmentally friendly method has been developed for the synthesis of thiol-substituted cyclohex-2-enones using a FeCl 3 -catalyzed condensation of cyclic 1,3-dicarbonyl compounds and aromatic/aliphatic thiols under solvent-free conditions at ambient temperature.

This alternate, improved, and efficient synthesis affords bosentan (I) without formation of reported impurities.

Ba2LaTaO6 is prepared by solid state reaction of a stoichiometric mixture of BaCO3, La2O3, and Ta2O5 (1350 °C, 6 h).

11 Trispirocompounds of type (IV) and (VI) are prepared and screened for their antifungal and antimycobacterial activities.

Base-mediated addition of acridones to allenylphosphonates/allenylphosphine oxides (OCH2CMe2CH2O)P(O)CH=C=CR1R2 {R1 = R2 = Me (1), R1 = R2 = [ $-{\rm CH}_{2^-}$ ]5 (2)}, Ph2P(O)C(H)= C=CR1R2 {R1 = R2 = Me (3), R1 = R2 = [ $-{\rm CH}_{2^-}$ ]5 (4)} and (EtO)2P(O)C(H)=C=CMe2 (5) in DMF results in the regiospecific formation of phosphono-acridones and acridonylphosphine oxides. The acridone addition products were also obtained in the reaction of allenes 1 and 2 with 9-chloroacridine under [Pd]-catalysed conditions, along with (unexpected) α-acridinyl substituted allenes. In contrast, 9-benzyl-6-chloro-purine reacted with 1 affording a β-substituted purinone phosphonate. Allenes 1–2 did not react with acridones in the absence of base (CsF), but in the presence of Pd(OAc)2/DMF (or DMA)/pivalic acid rearranged to give 1,3-butadienes probably via [Pd]-allyl complexes. The phosphono-acridones were amenable to Horner–Wadsworth–Emmons (HWE) reaction and led to N-substituted acridones. Key products have been characterized by single-crystal X-ray crystallography.

An efficient one-pot synthesis of fused thiazolopyridinone derivatives (5-amino-6,7-diphenyl-4,7-dihydro-3H-thiazolo[4,5-b]pyridin-2-ones) by four-component reaction of aldehyde, benzylcyanide, ammonium acetate and thiazolidine-2,4-dione in ionic liquid is reported. This protocol has the advantages of environmental friendliness, higher yields, less reaction time, and convenient operation. Also, optimization of the synthesized compounds has been done using Hyperchem 8.0.

The title compounds (V) and their precursors (III) show excellent antibacterial activities against Klebsiella pneumoniae and Escherichia coli as well as very good activity against Rhizoctonia solani and Fusarium oxysporum.

A facile one-pot synthesis of 3,4-dihydropyridine derivatives (III) (13 examples) under solvent- and catalyst-free conditions is developed.

via reaction of 2-chlorobenzimidazoles (I) with thiourea under microwave irradiation conditions, or alternatively and with comparable results, in PEG 600 or under physical grinding conditions