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Tris-hydroxymethylaminomethane has been demonstrated to be an efficient organocatalyst in diversity-oriented synthesis of medicinally prevalent spirochromenes by one-pot, three-component reactions between isatins, malononitrile, and enolizable C H acids like dimedone, 4-hydroxycoumarin, 4-hydroxy-N-methylquinolin-2-one, or in situ generated 2-methylpyrazolon-2-one. Biodegradability and extremely low cost of the catalyst are the noteworthy features of this chromatography-free protocol.

Solvent-free carbonylation of glycerol with urea to glycerol carbonate (GC) was achieved over heterogeneous Cu–Zn mixed oxide catalyst. Cu–Zn catalysts with different ratios of Cu:Zn were prepared using co-precipitation (CP) and oxalate gel (OG) methods. As compared to CuO–ZnO(2:1) catalyst prepared by oxalate gel (OG) method, much higher conversion of glycerol and highest selectivity towards glycerol carbonate (GC) was achieved with CuO–ZnO_CP(2:1) catalyst. Physicochemical properties of prepared catalysts were investigated by using XRD, FT-IR, BET, TPD of CO2 and NH3 and TEM techniques. The effect of stoichiometric ratio of Cu/Zn, calcination temperature of CuO–ZnO catalysts and effect of reaction parameters such as molar ratio of substrates, time and temperature on glycerol conversion to GC were critically studied. Cu/Zn of 2:1 ratio, glycerol–urea 1:1 molar ratio, 145 ​°C reaction temperatures were found to be optimized reaction conditions to achieve highest glycerol conversion of 86% and complete selectivity towards GC. The continuous expel of NH3 from reaction the mixture avoided formation of ammonia complex with CuO–ZnO catalyst. As a result of this, CuO–ZnO catalyst could be recycled up to three times without losing its initial activity.

We describe here our journey from the failure of our attempts in controlled oxidation of sulfides to sulfoxides using an Oxone®–KBr combination to our success in the development of a catalyst-free protocol for the oxidation of sulfides to sulfoxides using Oxone as an oxidant. We also describe the failure of our attempts at the oxidation of sulfides to sulfones using an excess of Oxone–KBr as well as Oxone, and our success towards the development of a rapid, scalable and chromatography-free protocol for the oxidation of sulfides to sulfones using diethylamine–Oxone as an unprecedented catalyst–oxidant combination.

A series of spirochromene-tethered 1,2,3-triazoles (1,2,3-triazolylspirochromenes) were designed and synthesized via click-chemistry-based one-pot five-component reaction between N-propargyl isatins, malononitrile, dimedone (or 4-hydroxyl-6-methyl-2H-pyran-2-one), arylalkyl halides, and sodium azide using cellulose-supported CuI nanoparticles (Cell-CuI NPs) as heterogeneous catalyst. All synthesized compounds were screened for inhibitory activity against Mycobacterium tuberculosis H37Ra (ATCC 25177) and Mycobacterium bovis BCG (ATCC 35743), in active as well as dormant state. During screening, compounds 6h, j, l were found to exhibit promising antimycobacterial activity against M. bovis BCG, while compounds 7d, h, l showed promising antimycobacterial activity against M. tuberculosis H37Ra as well as M. bovis BCG. The active compounds were found to be noncytotoxic to three human cancer cell lines (MCF-7, HCT116, and A549). The active compounds exhibited selectivity index >10, indicating potential as antitubercular agents. The active compounds were also evaluated for in vitro antibacterial activity, with five (6h, l, 7b, f, l) showing good antibacterial activity against Gram-positive as well as Gram-negative bacteria. Compounds 6h, j, l exhibiting promising activity against M. bovis BCG can serve as good leads for further modification and optimization.

Herein, diethylamine Dess–Martin periodinane has been demonstrated for the first time as an efficient catalyst–oxidant combination in a sequential, one-pot synthesis of medicinally privileged but difficult to access 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines via a pseudo-four component reaction between 2,6-disubstituted benzaldehydes, malononitrile, and thiols. Ambient reaction conditions, excellent yields, and total avoidance of conventional isolation as well as purification are the noteworthy merits of this developed protocol.

An enviro-economic protocol has been described for the synthesis of bis-tetronic acids by pseudo-three-component condensation between aldehydes/isatins and tetronic acid using sulfamic acid as a solid acid catalyst. Easy commercial availability of the catalyst at extremely low cost, excellent yields and avoidance of conventional purification procedures are the main merits of this energy efficient protocol.

A problem solving, environmentally benign, and diversity oriented protocol has been described for multicomponent synthesis of medicinally privileged 2-amino-3-phenyl (or methyl) sulfonyl-4H-chromenes by one-pot, three component condensation among aldehydes, phenyl (or methyl) sulphonyl acetonitrile, and α-naphthol, 3-dimethylamino phenol, 4-hydroxy-N-methyl-quinoline-2-one as well as 4-hydroxycarbazole, using diethylamine as an efficient organo catalyst. The catalyst employed is commercially available, inexpensive, and nontoxic. Ambient reaction conditions, very high yields, wide scope, and avoidance of conventional isolation as well as chromatographic purification have improved the practical utility of this protocol manifold.

An extremely simple, economical and environmentally benign protocol has been described for one-pot synthesis of 1-oxo-hexahydroxanthenes by pseudo three-component condensation between salicylaldehydes and dimedone, cyclohexane-1,3-dione or 5-methyl cyclohexane-1,3-dione using diethylamine as the catalyst. Based upon the mechanism of the reaction, the protocol has been extended towards the synthesis of tetraketones and bis-coumarins.

A series of spirochromenocarbazole tethered 1,2,3-triazoles were synthesized via click chemistry based one-pot, five component reaction between N-propargyl isatins, malononitrile, 4-hydroxycarbazole, aralkyl halides and sodium azide using cellulose supported CuI nanoparticles (Cell-CuI NPs) as the heterogeneous catalyst. Antiproliferative activity of all the synthesized compounds was investigated against panel of cancer cell lines such as MCF-7, MDA-MB-231, HeLa, PANC-1, A-549, and THP-1. Many of the synthesized compounds exhibited good anti-proliferative activity against breast (MCF-7 and MDA-MB-231) and cervical (HeLa) cancer cells with IC50 values less than 10 μM. In case of MCF-7 cells, among the nine compounds that showed good anti-proliferative activity, compounds 6f and 6j were found to be highly potent (IC50 = 2.13 μM and 4.80 μM, respectively). In case of MDA-MB-231, three compounds (6k, 6j and 6s) showed antiproliferative activity amongst which 6k was the most potent one (IC50 = 3.78 μM). On the other hand, in cervical cancer HeLa cells, compounds 6b, 6g, 6s and 6u showed excellent antiproliferative activity (IC50 = 4.05, 3.54, 3.83, 3.35 μM, respectively). All the compounds were found to be nontoxic to the human umbilical vein endothelial cells (HUVECs). AO and EtBr staining and fluorescence microscopy studies of the active compounds (IC50

A simple and efficient process for an exclusive mono-Michael addition of active methylene compounds to conjugated esters, nitriles and ketones is developed. An ionic liquid-mediated reaction is carried out at room temperature. A reaction carried out at 60 °C resulted in a double-addition product. A mechanism is proposed and supported by P31 and DOSY NMR analysis of the used ionic liquid.

Magnetically separable cobalt ferrite nanoparticles (CoFe2O4, NPS) have been demonstrated for the first time as an efficient catalyst in Petasis-Borono–Mannich (PBM) reaction between salicylaldehydes, sec. amines and aryl boronic acids to furnish alkylaminophenols in high yields. Relatively shorter reaction times, easy purification of the products and reusability of the catalyst for five consecutive runs without appreciable loss in it's activity are the noteworthy features of the developed protocol.

A simple, efficient and environmentally benign protocol has been developed for the one-pot, multicomponent synthesis of medicinally important tetrahydrobenzo[b]pyrans and pyran-annulated heterocycles using a commercially available, inexpensive, non-toxic, and biodegradable tris-hydroxymethylaminomethane (THAM) as a novel organocatalyst. Ambient reaction conditions, wide scope, avoidance of conventional isolation as well as purification techniques and the reusability of the catalyst for five consecutive runs have improved the practical utility of this multicomponent reaction protocol manifold.

Cellulose supported cuprous iodide nanoparticles (Cell-CuI NPs) have been demonstrated for the first time as an efficient heterogeneous catalyst in the click synthesis of 1,4-disubstituted 1,2,3-triazoles by a one-pot three component reaction between aralkyl/alkyl bromides, alkynes and sodium azide in water. The catalyst has been characterized by XRD, HRTEM, SEM, ICP–AES, EDS as well as IR spectroscopy. It was found to be reusable for five consecutive runs without significant loss of activity.

A simple, economical, and environmentally benign protocol has been described for one-pot synthesis of medicinally privileged 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines by three-component condensation between aldehyde, malononitrile, and thiol using diethylamine as a catalyst. Ambient temperature and avoidance of conventional work-up as well as purification procedure qualify this cost-effective protocol for “green synthesis.”

Diethylamine has been demonstrated to be an efficient organocatalyst in the diastereoselective synthesis of Bcl-2 protein antagonist (HA-14-1) and of its structural analogues by one-pot condensation between salicylaldehyde and three different C–H acids, viz. ethyl cyanoacetate, phenylsulfonyl acetonitrile, and malononitrile. Easy commercial availability of the catalyst at extremely low cost and avoidance of conventional work-up as well as purification procedures qualifies this scalable protocol for a “near-ideal synthesis”.

In this study, azetidine derivatives were evaluated for their potency as dopaminergic antagonist. The study comprised derivatives substituted in 3-position with amide moiety. Further, the phenyl moiety of amide was modified at 2, 3, or 4-position. The substituted compounds were biologically evaluated for their affinity for D2 and D4 receptors. The most potent D2 and D4 antagonist among these compounds appeared to be the N-(1-benzhydryl-azetidin-3yl)-2-bromo-benzamide and N-(1-benzhydryl-azetidin-3yl)-4-bromo-benzamide, respectively. Various docking interactions of CPPMA with the D4 receptor and the same for compound 5 i.e., N-(1-benzhydryl-azetidin-3yl)-4-bromo-benzamide were found to have good correlation with observed biological activity.

An extremely simple, high yielding, highly rapid and solvent-free protocol has been described for hydrophosphylation of aldehydes using potassium phosphate as catalyst. Easy commercial availability of the reusable catalyst, operational simplicity at ambient temperature and avoidance of conventional work-up as well as purification procedure makes this solvent-free protocol a near-ideal synthesis.

Magnetically separable cobalt ferrite nanoparticles (CoFe2O4, NPS) have been demonstrated for the first time as an efficient catalyst in Petasis-Borono–Mannich (PBM) reaction between salicylaldehydes, sec. amines and aryl boronic acids to furnish alkylaminophenols in high yields. Relatively shorter reaction times, easy purification of the products and reusability of the catalyst for five consecutive runs without appreciable loss in it's activity are the noteworthy features of the developed protocol.

A simple and efficient process for an exclusive mono-Michael addition of active methylene compounds to conjugated esters, nitriles and ketones is developed. An ionic liquid-mediated reaction is carried out at room temperature. A reaction carried out at 60 °C resulted in a double-addition product. A mechanism is proposed and supported by P31 and DOSY NMR analysis of the used ionic liquid.

Diethylamine has been demonstrated for the first time to be a highly efficient organocatalyst in the solvent-free synthesis of β-phosphonomalononitriles by a three component condensation of aldehyde, malononitrile and dialkyl phosphite at ambient temperature. The applicability of the same catalyst in the synthesis of diethyl (2-amino-3-cyano-chromene-4-yl) phosphonic acid esters has also been described.

Lithium tetrafluoroborate has been demonstrated for the first time to be an efficient catalyst in intermolecular aza-Michael addition aromatic amines to electron deficient alkenes. Suitability of the same catalyst in intramolecular aza-Michael addition leading 2-aryl-2,3-dihydroquinolin-4(1H) ones has also been described.

A silica supported orthophosphoric acid catalyst (H3PO4. SiO2) was prepared by stirring silica gel (100–200mesh) with orthophosphoric acid in chloroform at room temperature. The catalyst was characterized by scanning electron microscopy (SEM) and energy dispersion analytical X-ray (EDX). It demonstrated excellent activity, chemoselectivity, and recyclability for oxathioacetalization of aldehydes.

A basic, ester functionalized, imidazolium based ionic liquid (IL2), 3-Methyl-1-(ethoxycarbonylmethyl)imidazolium hydroxide was designed eyeing in situ generation and stabilization of palladium nanoparticles for palladium catalyzed Heck reaction of haloarenes and olefins. This phosphine-free Pd-IL catalyst demonstrated excellent activity and reusability at relatively low reaction temperature (80 °C) for a wide spectrum of haloarenes including chloroarenes. The relatively low reaction temperature could be attributed to in situ generation of uniform and spherical palladium nanoparticles (~ 5 nm).

An efficient method for synthesis of 1,8-dioxo-octahydroxanthenes using EPZ-10 as a heterogeneous catalyst is developed. In this method, aldehydes and dimedone / cyclohexane-1,3-dione are heated at 70 °C in the presence of a catalytic amount of EPZ-10 in water as a universal solvent, affording the corresponding 1,8-dioxo-octahydroxanthenes in moderate to excellent yields. Also, domino Knoevenagel / hetero-Michael-addition reaction is described in water without any catalyst with excellent yields. The major advantages of this method are excellent yields, short reaction time, and ease of operation. This green protocol works well with dimedone as well as cyclohexane-1,3-dione.

An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, 1,3-diketone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol. An efficient, rapid, one-pot synthesis of tetrahydrobenzo[b]pyran is achieved via a three-component reaction of aldehydes, dimedone, malononitrile in 20% ethanol using anhydrous potassium phosphate as a catalyst at room temperature. The key advantages are the short reaction time, high yields, simple work-up, inexpensive catalyst and purification of products by non-chromatographic methods, i.e. by simple recrystallization from ethanol.

An efficient method for the one-pot synthesis of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles has been developed using trichloroisocyanuric acid (TCCA) at ambient temperature. A wide variety of aromatic as well as heterocyclic aldehydes exhibit condensation with a variety of acylhydrazines followed by oxidative cyclization to yield corresponding unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles. The mild nature of the synthesis and short reaction time are notable advantages of the developed protocol.

Sulfamic acid catalyzed solvent-free protocol has been developed for the synthesis of α-aminophosphonates by three component condensation between aldehydes, amines and diethyl phosphite at ambient temperature.

Lithium tetrafluoroborate-catalyzed one-pot, highly efficient, and solvent-free protocol has been developed for the synthesis of α-aminonitriles from aldehydes/ketones, amines, and trimethylsilyl cyanide.

o-Aminoaryl ketones underwent smooth condensation with a variety of α-methylene ketones in the presence of NaHSO4.silica gel as a solid acid catalyst to afford 1,2,3-trisubstituted quinolines in excellent yields. The reusability of the catalyst has made the protocol simple, cost–effective and environmentally benign.

The entitled organocatalyst is non-toxic, cheap, bio-degradable and easy to handle, and is used in the synthesis of pyran-annulated heterocycles for the first time.

An efficient method has been developed for the chemoselective synthesis of acylals from aldehydes and acetic anhydride in the presence of silica sulfuric acid as a reusable solid acid catalyst under solvent-free conditions. Ketones are found to remain unaffected under the reaction conditions. The deprotection of acylals has also been achieved using SSA in methanol medium.

Silica sulfuric acid (SSA) was found to be a mild, efficient and reusable solid acid catalyst in electrophilic substitution reaction of indoles with carbonyl compounds to afford the corresponding bis(indolyl)alkanes in excellent yields under solvent-free conditions.

A simple one pot method, involving sequential Knoevenagel condensation of Meldrum's acid with aromatic aldehydes, conjugate reduction of ylidene Meldrum's acid using sodium borohydride followed by alkylation, to prepare mixed dialkylated derivatives of Meldrum's acid is described.

A simple, mild, and efficient protocol for chemoselective protection of alcohols over phenols as tetrahydropyranyl ethers and their deprotection using silicasulphuric acid as a reusable solid acid catalyst is described.

A simple method for synthesis of methylene dioximes by reaction of ketoximes with dichloromethane in the presence of aqueous sodium hydroxide solution using poly (ethylene glycol)‐400 (PEG‐400) as a phase transfer catalyst is described.

Azo-bis nitriles were prepared in good yields and high purity by oxidation of corresponding 1,2-bis-dialkylcyano hydrazines using oxone-potassium bromide in aqueous medium.

A simple and practical halogenation of activated arenes using a reagent combination of potassium halide and oxone® in water-acetonitrile medium is presented. The halogenated products were obtained with good yields and in high purity.

Knoevenagel condensation of Meldrum's acid (1) with benzaldehyde, anisaldehyde, furfural, cinnamaldehyde and acetone gave the corresponding alkylidene derivatives (3) which were reduced with sodium borohydride to yield alkyl Meldrum's acids (4). Reaction of (4) with pyridine-D2O at high temperature furnished α-dideuterated acids (6). The reduction of alkylidene derivatives (3) with sodium borodeuteride yielded β-deuterated alkyl Meldrum's acids (7) which on hydrolysis and decarboxylation yielded β-deuterated acids (9). α,α,β-Trideuterated acids (11) were prepared by hydrolysis and decarboxylation of (7) with pyridine-D2O. Copyright © 1999 John Wiley & Sons, Ltd.

(2003). A SHORT SYNTHESIS OF ar-TODOMATUIC ACID AND DIHYDRO-ar-TURMERONE BY THE HECK REACTION. Organic Preparations and Procedures International: Vol. 35, No. 4, pp. 418-420.

An efficient and fast synthesis of the title compounds (III) (11 examples) is achieved by reaction of salicylaldehyde (I) with Meldrum′s acid using potassium phosphate as an inexpensive catalyst.

An efficient method for synthesis of 1,8-dioxo-octahydroxanthenes using EPZ-10 as a heterogeneous catalyst is developed. In this method, aldehydes and dimedone / cyclohexane-1,3-dione are heated at 70 °C in the presence of a catalytic amount of EPZ-10 in water as a universal solvent, affording the corresponding 1,8-dioxo-octahydroxanthenes in moderate to excellent yields. Also, domino Knoevenagel / hetero-Michael-addition reaction is described in water without any catalyst with excellent yields. The major advantages of this method are excellent yields, short reaction time, and ease of operation. This green protocol works well with dimedone as well as cyclohexane-1,3-dione.

Methyl aryl ethers are deprotected in high yields using pyridine hydrochloride in the absence of solvent under microwave irradiation.

A simple and practical halogenation of activated arenes using a reagent combination of potassium halide and oxone® in water-acetonitrile medium is presented. The halogenated products were obtained with good yields and in high purity.