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A combined theoretical and experimental investigation on a pharmaceutically important binary complex 3,3'-[(3-benzimidazolyl)methylene] bis (4-hydroxy-2 H -1-benzopyran-2-one): 5-methyl-1,3-thiazol-2(3 H )-imine is presented in this manuscript. The compound crystallizes in the monoclinic crystal system with space group Cc with unit cell parameters: a = 19.8151(8) A, b = 15.2804(6) A, c = 8.3950(4) A, β = 94.0990(10)°, V = 2535.36(19) A 3 , Z = 4, T = 296(2) K, μ(MoKα) = 0.184 mm -1 , Dcalc = 1.490 g/cm 3 , 35833 reflections measured (5.332° ≤ 2Θ ≤ 56.678°), 6168 unique ( R int = 0.0467, R sigma = 0.0388) which were used in all calculations. The final R 1 was 0.0435 (I > 2σ(I)) and wR 2 was 0.1073 (all data). The crystal structure has been determined by the conventional X-ray diffraction method, solved by direct methods and refined by the full matrix least squares procedure. Intramolecular hydrogen bonding of the type C–H⋅⋅⋅O and O–H⋅⋅⋅O is present and the crystal structure stabilizes via N–H…O, C–H…N and O–H…N intermolecular interactions. The optimized structural parameters have been compared and the parameters like ionization potential, electron affinity, global hardness, electron chemical potential, electronegativity, and global electrophilicity based on HOMO and LUMO energy values were calculated at B3LYP/6-311G(d,p) level of theory for a better understanding of the structural properties of the binary complex.

The present work describes an efficient and environmentally benign four component synthesis of structurally diverse substituted pyrido-pyrimidines involving the reaction of barbituric acid, 4-hydroxy 6-methyl 2-pyrone, an aromatic aldehyde and ammonium acetate in low transition temperature mixture (LTTM) (glycerol:proline: 1:1). The LTTM serves as green solvent which is an inexpensive, nontoxic and plays a dual function (reusable catalyst and solvent), and is found to be an excellent reaction endorsing medium. The present protocol offers some advantages such as easy work up, shorter reaction time, an excellent yield with higher atom economy, maximum reaction efficiency with an excellent green chemistry metrics. The synthesized compounds have been evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay as well as molecular docking studies performed on myeloperoxidase enzyme. Tested scaffolds exhibits an excellent results of virtual screening and antioxidant activity.

The expansion of proficient and environmentally benign synthetic protocols has engrossed increasing attention in recent organic syntheses in view of the mounting concern over the environment. As part of this green concept, our group designed novel LTTM by using Glycerol and proline (1:1) at reflux condition, and effectiveness of novel DES or LTTM has been studied for the synthesis of 7-(aryl)-10-methyl-6H,7H-chromeno[4,3-d]thiazolo[3,2-a]pyrimidin-6-one derivatives via Multicomponent reaction. The synthetic methodology with the use of novel LTTM as green solvent and inexpensive, biodegradable, plays a dual role (recyclable catalyst and solvent) with its operational simplicity and maximum greener synthetic efficiency with green chemistry metrics calculations will be attractive for academic and industrial research. The synthesized derivatives have been evaluated for mosquito larvicidal bioassay using two mosquito species namely Aedes aegypti and Culex quinquefasciatus.

In the present work, we have reported the synthesis of benzimidazoles functionalized crown ether derivatives of 4-formyl benzo-15-crown-5/4,4′-diformyl dibenzo-15-crown-5 and substituted diamine py...

An efficient one-pot synthesis of novel pyrazolo[3,4-b][1,8]naphthyridine and pyrazolo[3,4-d]pyrimido[1,2-a]pyrimidine derivatives has been investigated from the reaction of 2-amino (pyrimidine or pyridine), aromatic aldehydes and 3-methyl-1-phenyl-2-pyrazolin-5-one. All synthesized compounds were evaluated for in vivo anti-inflammatory activity using carrageenan-induced rat paw edema assay. Compounds 4a, 4e, 4g, 5a, 5b (80%) and 5c (86%) showed good to excellent results when compared with the anti-inflammatory active standard drug diclofenac Na (93%). On the basis of the structure–activity relationship, the anti-inflammatory activity of pyrazolo[3,4-d]pyrimido[1,2-a]pyrimidine derivatives has been found to be much better than pyrazolo[3,4-b][1,8]naphthyridine derivatives.

The present study describes the synthesis and in vitro anticancer activity of novel piritrexim analogs against human breast cancer cell line MCF-7 and a normal Vero monkey cell line. The scheme involves the formation of 3-(4-nitrophenyl)-4-phenyl-1,8-naphthyridin-2-amine accomplished by the condensation reaction of 4-nitrophenyl acetonitrile, aromatic aldehyde, and 2-aminopyridine using acetic acid as a catalyst. The selected synthesized compounds have been screened against a human breast cancer cell line MCF-7 and a normal Vero monkey cell line, out of which the compounds 4b, 4e, 4f exhibited higher potency (GI50 [

A simple, proficient and an elegant synthetic route for the synthesis of spiroxanthene and dibarbiturate derivatives has been developed under the umbrella of green chemistry. The operational simplicity, good to excellent product yields, easy workup procedures and non-chromatographic purification procedure are remarkable features of this protocol. Furthermore, the use of low transition temperature mixture as green reaction medium reduces burden on environment and makes the present method environmentally sustainable. The calculated values of green chemistry metrics are found to be in well agreement with ideal values signifying greenness of developed protocol.

An efficient green protocol has been investigated for the synthesis of pyrimido[4,5-b]quinolines derivatives via one-pot three-component condensation of 4-chloro aniline, aromatic aldehyde and barbituric acid using low transition temperature mixtures as new generation and sustainable solvents. The process was accomplished with the use of greener and recyclable reaction media, simple methodology, easy workup procedures and no chromatographic purification with high yield. This new approach is expected to discover some significance in combinatorial synthesis of biologically active scaffolds.

A practical, two-step synthesis of crown ether functionalized pyrimidines has been developed. The reaction conditions have been optimized, and the protocol is generalized for series of substrates. These newly synthesized compounds exhibited antimicrobial activity against bacterial strains Staphylcoccus aureus (Gram-positive) and Escherichia coli (Gram-negative). These compounds were also found to be potent antifungal agents Aspergillus niger and Candida albicans strains, respectively.

The present work describes sustainable, catalyst free and bio-oriented multicomponent synthesis of 2-amino-3-cynospiro (5H-indeno[1,2-b]pyran-4,3′-indoline)-2′5,-dione using isatin, malononitrile and 1,3-indandione. This study provides a facile synthesis of indeno-spiro compounds and is further supported with molecular docking, physico-chemical parameter and cytotoxicity study. The synthesized compounds were screened against breast carcinoma cell lines (MCF7, MDA-MB-435) and normal Vero monkey cell lines. Among all the tested compounds, the bromo- and chloro- substituted indeno-fused spirooxindole derivatives (entry B and D) were found to show selective potency against the MDA-MB-435 cancer cell lines exhibiting GI50 value of 1.8 and 2.1 µM respectively. The selected compounds were also screened against the normal Vero monkey cell line, which showed good to excellent selectivity against inhibition of cancer cells. Furthermore, the in vitro confocal microscopy cell imaging of selected compounds showed cellular shrinkage and apoptosis in the cancer cells suggesting that the indeno-fused spirooxindoles can be explored as selective estrogen negative receptors with a safety profile.

A series of novel 7-phenyl-7,12-dihydrobenzo(h)pyrido[2,3-b]naphthydrin-6(5H)-one were synthesized by a one-pot three-component condensation of 2,4-dihydroxyquinoline, 2-amino pyridine and various aromatic aldehydes with sulfamic acid as an enviro-economic catalyst. The salient features of this method consist of high atom economy and yields, short reaction time, non-carcinogenic solvents, and chromatography-free work-up procedure. Fascinatingly, the catalyst can be reused for up to four cycles giving good to excellent yields. By employing this method, a series of 14 pyrido[2,3-b]naphthydrin compounds were synthesized. This procedure is projected as a green avenue in the combinatorial synthesis of biologically active naphthydrin derivatives.

A proficient and meticulously designed diasterioselective, multicomponent, one-pot synthesis of densely substituted piperidine derivatives has been elaborated using polystyrene sulfonic acid catalyst via tandem reactions of 1,3-dicarbonyl compounds, aromatic aldehydes and various amines. Shorter reaction times, high yields and a polymer-supported inexpensive catalyst are the noteworthy aspects of the scaffold.

The new facile approach has been developed for the synthesis of spiro [diindenopyridine-indoline] triones under the umbrella of green chemistry. The developed protocol is endowed with the use of low transition temperature mixture as a green reaction medium, operational simplicity, easy workup procedures, good to excellent product yields, and non-chromatographic purification procedure. Since indenone fused motifs have a broad spectrum of biological activities, this protocol is expected to find application in the combinatorial synthesis of biologically active compounds.

Objective of the present work was to evaluate the anti-inflammatory, ulcerogenicity and cyclooxygenase activity of indenopyrimidine derivatives. Anti-inflammatory activity of the tested compounds is investigated by carrageenan-induced rat paw edema assay. Compounds A1, A6, A7 and A12 exhibit the comparable anti-inflammatory activity (79.33-81.33%) to the standard drug diclofenac sodium (85.33%), while A6, A7, A9, A12 and A14 show better ulcer index than the reference standard diclofenac sodium. To rationalize the anti-inflammatory activity, docking experiments are performed to study the ability of these compounds to bind into the active site of COX-2 enzyme.

A highly competent-diversity oriented synthesis of coumarin core derivatives using a Knoevenagel condensation followed by Michael addition and subsequent cyclization in the presence of (±)-camphor-10-sulfonic acid in a water/ethanol (1:1) solvent system is depicted. Furthermore, easy workup procedures with good yield, rapid reactions with high atom economy, and catalyst recyclability are the fascinating features of the procedure.

Dibenzothiazolyldibenzo-18-crown-6-ether was designed and synthesized by formylation of dibenzo-18-crown-6-ether followed by condensation with 2-aminothiophenol. A simple and rapid UV-Visible spectrophotometric method is developed for detection of trace of palladium ions. Furthermore it was assessed for antimicrobial activity against bacterial strains Staphylococcus aureus (Gram+ve), Escherichia coli (Gram−ve) as well as fungal strains Aspergillus niger and Candida albicans respectively.

A simple methodology has been developed for the synthesis of diverse members of multifunctionalized 4-hydroxy-2-methyl-6-(phenyl)pyrimidine-5-carbonitrile derivatives via multicomponent reaction of aromatic aldehydes, ethyl cyanoacetate, and acetamidine hydrochloride using a quantitative amount of NaOH in dry DMF at 80 °C in a single procedural step. The carbon skeleton of synthesized compounds resembles the bacimethrin, an antibiotic active against several yeast and bacteria. The anti-inflammatory activities of all the synthesized compounds were assessed on Wistar rats using diclofenac sodium as a standard reference. The compound AC1, 2, 5, 9, and AC10 showed promising anti-inflammatory activity (80–83 %) in comparison with diclofenac sodium (85 %) in the carrageenan-induced rat paw edema assay, which is the key finding of this article. The synthesized 4-hydroxy-2-methyl-6-(phenyl)pyrimidine-5-carbonitrile derivatives shown promising anti-inflammatory activity (80–83 %) in comparison with diclofenac sodium (85 %) in the carrageenan-induced rat paw edema assay.

An uncatalyzed efficient synthesis of bioactive pyridine derivatives has been investigated for the first time by a three-component sequential multicomponent reaction tackled with aromatic aldehydes, malononitrile, and 1,3-indandione via Knoevenagel condensation followed by Michael addition. The difference between the domino multicomponent and sequential multicomponent reaction is emphasized by this methodology. The reaction proceeds at ambient temperature without frequently useful N-source like ammonium salt for the construction of N-heterocycles, which makes this protocol a novel synthetic route for the preparation of the indenopyridine skeleton.

A novel series of benzo crown ether (dibenzo 18-crown-6 ether, benzo 18-crown-6 ether, and benzo 15-crown-5 ether) functionalized enamines derivatives from amino benzo crown ether (4-amino dibenzo 18-crown-6 ether, 4-amino benzo 18-crown-6 ether, 4-amino benzo 15-crown-5 ether) and substituted 3-(dimethylamino)-1-phenylprop-2-en-1-one compounds have been synthesized. All the synthesized compounds were characterized by infrared, 1H NMR, 13C NMR, distortionless enhancement polarization transfer, and mass and elemental analysis techniques. The cation recognition property for benzo crown ether enamine 8a was studied by absorption and fluorescence spectroscopy.

A series of novel 18-crown-6 ether functionalized bis-benzimidazole derivatives (3a–g) have been synthesized by reacting various substituted ortho-phenylene diamines and pyridine diamines with 4,4′-diformyl dibenzo-18-crown-6 ether (1). The required starting material 4,4′-diformyl dibenzo-18-crown-6 ether (1) was prepared by Duff formylation method. All synthesized novel molecules have been identified on the basis of infrared (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass spectroscopy (MS), and elemental analyses. The title compounds (3a–g) were tested for antifungal activity against Aspergillus niger, Trichothecium sp., Rhizopus sp., and Sclerotium rolfsii fungi species using agar well diffusion method, showing mild to good results.

The new green approach has been used for the reaction of indole with various carbonyl compounds. The attractive features of this protocol are the use of green reaction medium, good to excellent product yields, operational simplicity, easy workup procedures and the use of group assistance purification process avoiding chromatographic purification. This protocol is expected to find application in the combinatorial synthesis of biologically active compounds, since indole and chromone motifs have a broad spectrum of biological activities.

The quest to develop an environmentally friendly, sustainable protocol for immensely bioactive spirooxindole derivatives has encouraged to explore oxalic acid dihydrate: proline low transition temperature mixture as a new designer solvent for the said synthesis at room temperature. It has been successfully applied for the three component reaction of isatin, malononitrile or ethyl cyanoacetate and 1,3–dicarbonyl compounds for the first time. Moderate to good yield of the products, shorter reaction time, energy efficiency, chromatography-free purification process, recyclability and high atom economy are the captivating feature of this protocol which will find applications in multi-component, diversity-oriented synthesis.

Protic ionic liquids (PILs), which are easily produced through the combination of a Bronsted acid and Bronsted base, such as [Mim]Ac and 1,4-diazabicyclo[2.2.2]octane (DABCO):AcOH:H2O (1:1:3), were found to be lucid, tunable tool for synthesis of various heterocyclic motifs such as phthalazinediones, quinoxalines and benzopyrans. These PILs were found to be efficient for synthesis of diverse heterocyclic derivatives, along with demonstrating noteworthy aspects such as high yields, isolation of pure products without column chromatography and recyclable reaction media.

A natural biosurfactant, a biobased green acidic catalyst for cyclocondensation of salicylaldehyde (or 2-hydroxy naphthaldehyde) and cyclic 1,3-diketones for benzopyran synthesis in water has been reported for the first time. The structures of the final compounds were confirmed with the aid of IR, 1H NMR, and 13C NMR spectroscopy. Lemon extract as a natural biosurfactant provides a micellar media for effective organic transformation. The CMC of lemon extract was determined by the conductivity method. In comparison to the conventional methods, this synthetic pathway complies with several key requirements of green chemistry principles such as the utilization of renewable feedstock, auxiliary aqueous conditions, waste prevention, and atom economy along with the use of biodegradable catalyst. Thus, the reported protocol offers an attractive option because of its ecological safety, environmental acceptance, sustainability, and low-cost straightforward work-up procedure.

The alternate synthesis of indeno-pyridine and indeno-pyran derivatives have been described by an unprecedented, green, one-pot reaction of aromatic aldehydes, malononitrile, and indane 1,3-dione. The formation of either indeno-pyridine or indeno-pyran derivatives based on a precise change in the Michael addition of indane 1,3-dione or malononitrile on Knoevenagel product during the progress of reaction has been investigated. The reaction completed up to 30 min of time using CuO nanoparticles in water at an ambient temperature renders the protocol novel and environment friendly. All the synthesized compounds have been confirmed on the basis of their spectroscopic data. The CuO nanoparticles have been prepared by coprecipitation method and characterized by SEM, PXRD spectroscopy, and UV spectroscopy.

A simple, clean and convenient one-pot method has been developed for the synthesis of 4-phenyl-3,4-dihydro-1H-indeno[1,2-d]pyrimidine-2,5-dione and 4-phenyl-2-thioxo-1,2,3,4-tetrahydro-5H-indeno[1,2-d]pyrimidine-5-one by multicomponent condensation of 1,3-indanedione, aromatic aldehydes and urea/thiourea using phosphorus pentoxide in ethanol under reflux conditions. The simple workup procedure and moderate to good yields within short time are some important features of this protocol. The synthesized compounds have been interpreted on the basis of their spectroscopic data.

The present study describes an alkaline water–ethanol mediated series of combinatorial synthesis of 2-amino-4-phenyl-5-H-indeno[1,2d]pyrimidine-5-one derivatives through sequential multicomponent reaction of 1,3indandione, aromatic aldehydes, and guanidine hydrochloride along with their anticancer evaluation. The effect of sequential addition of the components in the configuration of the desired product has been studied by UV–visible absorption spectroscopy. The synthetic method obeys most of the green chemistry principles in regard to high atom economy and greener, nontoxic, and noncarcinogenic solvent system (water–ethanol). The selected synthesized compounds have been screened against the human breast cancer cell line MCF7, human colon cancer cell line HT29, and normal viro monkey cell line, out of which 2-amino-4-(4-methoxyphenyl)-5H-indeno[1,2-d]pyrimidin-5-one showed significant potency toward human breast cancer cell line (MCF7).

An innovatively designed novel crown ether functionalized imidazolium-based reusable acidic ionic liquid [crown ether MIm] [HSO4] has been efficiently implemented for the synthesis of pyrazole derivatives using various substituted enaminones, hydrazine hydrate and phenyl hydrazine under solvent-free conditions. Structural novelty and task efficiency of the catalyst, high yields of desired products, greener approach attributing high atom economy and solvent-free conditions render this protocol suitable to cope with the current demand in contemporary organic chemistry. The inventive idea of utilizing crown ether functionalized ionic liquid as a catalyst was for the first time demonstrated in this protocol.

Polystyrene-supported sulfonic acid has been found to be an efficient catalyst for the one-pot, three-component synthesis of 2H-indazolo[2,1-b]phthalazinetriones in greener solvent glycerol. Use of greener solvent glycerol along with a polymer-supported, low toxic, and inexpensive catalyst renders the method eco-friendly. High yields, simple product isolation procedure, and fluorescent and electroluminescent natures of the products are the noteworthy aspects of this protocol.

New crown ether-functionalized benzimidazoles was designed and synthesized via formylation of dibenzo-18-crown-6 followed by condensation with different o-phenylene diamines. The complexation properties of crown ether-functionalized benzimidazoles with various metals (K+, Ca2+, Ba2+, Co2+, Hg2+) were examined using UV–vis spectroscopy. Hg2+ showed a well-defined peculiar absorption maximum at 366 nm exclusively. All these newly synthesized compounds were screened for antifungal activity against Aspergillus niger and Aspergillus oryzae, respectively.

The two acridinedione derivatives 1 [3,3,6,6-tetramethyl-9-(4-methoxyphenyl)-3,4,6,7,9,10-hexahydro-2H,5H-acridine-1,8-dione (C24H29NO3)] and 2 [3,3,6,6-tetramethyl-9-(4-methylphenyl)-3,4,6,7,9,10-hexa-hydro-2H,5H-acridine-1,8-dione (C24H29NO2)] were synthesized and their crystal structures were determined by direct methods. The asymmetric unit of compound 1 contains two independent molecules. The 1,4-dihydropyridine (DHP) ring adopts boat conformation in both 1 and 2. In 1 the dione rings exist in sofa conformation (for both the crystallographically independent molecules) while the corresponding rings in 2 adopt half chair and sofa conformations, respectively. The crystal packing is stabilized by intermolecular N–H⋯O and C–H⋯O interactions in compound 1 and N–H⋯O interactions in compound 2.

A novel, highly efficient and recyclable Bronsted acidic ionic liquid ([CMIM][CF3COO]) has been successfully implemented for the synthesis of acridinediones in aqueous media. Recyclability of novel catalyst, high yields, use of environmentally benign aqueous media as solvent, simple product isolation, high atom economy and sidestep to column chromatography are the noteworthy features of this protocol. This protocol is competent for producing wide library of acridinediones in good to excellent yields. Furthermore, molecular structure and relative stereochemistry of 4c and 4s derivatives were confirmed by single-crystal X-ray diffraction.

A series of novel fluoroionophore bearing derivatives of benzo-15-crown-5 were synthesized by the amination of benzo-15-crown-5 followed by condensation with different quinones in the presence of titanium tetrachloride (TiCl4 )a nd 1,4-diazabicyclo-(2.2.2)octane. The compounds were characterized by infrared, 1 Ha nd 13 C nuclear magnetic resonance, mass spectroscopy and elemental analysis. Absorption and fluorescence spectral characteri stics of these compounds were studied. It was observed that the anthraquinone derivative was acting as an Hg 2+ ion sensor. Copyright © 2013 John Wiley & Sons, Ltd.

A convenient, eco-friendly and economic method for Knoevenagel condensation of aromatic aldehydes with active methylene compounds using calcined eggshell (CES) as an efficient natural catalyst in aqueous medium has been reported. CES is a new, ecologically safe and inexpensive green catalyst obtained from renewable resources.

(±)-Camphor-10-sulfonic acid is used for the synthesis of triazolo[1,2-a]indazole-triones and spiro triazolo[1,2-a]indazole-tetraones by condensation reaction of dimedone, urazole and aromatic aldehydes or isatin. The noteworthy aspects of this new method are high yields, high atom efficiency, use of non-toxic solvent, mild conditions, simple workup and synthesis of complex molecules using an eco-friendly, inexpensive catalyst.

Product formation in this efficient, green, three-component one-pot reaction is simply controlled by the sequence of addition.

S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities.

The reaction of primary aromatic amines with aryl aldehydes is found to be catalyzed by lemon juice as natural acid under solvent-free conditions to give the corresponding Schiff bases in good yields. This eco-friendly reaction has many advantages like economical, environmental, mild reaction conditions and simple work-up with high product yield.

An ecofriendly and economical method of Knoevenagel condensation of aromatic aldehydes with malononitrile catalyzed by lemon juice, a natural catalyst, in the absence of any solvent is described.

A series of 2,3,4-trisubstituted quinoline derivatives have been synthesized by reactions between 2-aminoaryl ketones and dialkyl acetylenedicarboxylate. The synthetic pathway allows for the direct construction of said quinoline derivatives in pyridine/ethanol at ambient temperature through a zwitterion intermediate. J. Heterocyclic Chem., (2011)

An efficient and simple method has been reported for the synthesis of 2,3,4-trisubstituted quinolines through zwitterion intermediate under reflux condition in presence of sulfuric acid. The formed dicarboxylate subsequently undergoes transesterification in various alcohols with good yields. Most of the synthesized compounds are newly reported characterized by spectroscopic method. J. Heterocyclic Chem., (2011).

A simple and efficient approach towards one step synthesis of 6-amino-5-cyano-4-phenyl-2-mercapto pyrimidine and its hydroxyl derivatives have been developed by three component condensation of aromatic aldehydes, malononitrile and thiourea/urea in presence of phosphorus pentoxide (Scheme 1).