A novel three-component method for the synthesis of triazolo[1,2-a]indazole-triones

An efficient synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives based on the three-component condensation of urazole, dimedone and aromatic aldehydes under solvent-free conditions is described.     

One-pot and efficient synthesis of triazolo[1,2-a]indazole-triones via reaction of arylaldehydes with urazole and dimedone catalyzed by silica nanoparticles prepared from rice husk

A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.     

Solvent-free,four-component synthesis of 3,4,7,8-tetrahydro-3,3-dimethyl-11-aryl-2<Emphasis Type="Italic">H</Emphasis>-pyridazino[1,2-a]indazole-1,6,9(11<Emphasis Type="Italic">H</Emphasis>)-triones; using 1-butyl-3-methylimidazolium hydroxide ([bmim]OH) as a green and reusable catalyst

A series of 3,4,7,8-tetrahydro-3,3-dimethyl-11-aryl-2H-pyridazino[1,2-a]indazole-1,6,9(11H)-trione derivatives have been synthesized via one-pot, four-component reaction in the presence of 3-methyl-1-butyl imidazolium hydroxide as an efficient catalyst. A broad range of structurally diverse aldehydes (aromatic aldehydes bearing electron withdrawing and electron releasing groups) was applied successfully, and corresponding products were obtained in good to excellent yields without any by-product. The catalyst was stable during the reaction process and could also be reused several times with consistent activity.     

Highly efficient synthesis of triazolo[1,2-a]indazole-triones and novel spiro triazolo[1,2-a]indazole-tetraones under solvent-free conditions

A new, convenient, and high yielding procedure for the synthesis of triazolo[1,2-a]indazole-triones by the condensation reaction between dimedone, aryl aldehydes, and ueazoles in the presence of a catalytic amount of sulfonated polyethylene glycol (PEG-SO₃H) as a highly stable and reusable eco-friendly degradable polymeric catalyst is described under solvent-free conditions. This procedure has also been applied successfully for the synthesis of novel spiro triazolo[1,2-a]indazole-tetraones.     

Grindstone Chemistry: Design,One-Pot Synthesis,and Promising Anticancer Activity of Spiro[acridine-9,2′-indoline]-1,3,8-trione Derivatives against the MCF-7 Cancer Cell Line

In this study, the synthesis of one-pot 10-phenyl-3,4,6,7-tetrahydro-1H-spiro [acridine-9,2′-indoline]-1,3,8-trione derivatives was achieved via a four-component cyclocondensation reaction, which was carried out in solvent-free conditions, and using p-toluenesulfonic acid (p-TSA) as a catalyst. The product was confirmed by FT-IR, ¹H-NMR, ¹³C-NMR, mass spectra, and elemental analysis. Furthermore, the anticancer activity was screened for all compounds. Among these compounds, compound 1c was more effective (GI₅₀ 0.01 µm) against MCF-7 cancer cell lines than standard and other compounds. Therefore, the objective of this study was achieved with a few promising molecules having been demonstrated to be potential anticancer agents.     

A novel three-component method for the synthesis of spiro[chromeno [4′,3′:4,5] pyrimido[1,2-b] indazole-7,3′-indoline]-2′,6(9H)-dione

A green, efficient, and rapid procedure for the synthesis of novel spiro[chromeno[4′,3′:4,5] pyrimido[1,2-b]indazole-7,3′-indoline]-2′,6(9 H)-dione derivatives has been developed by one-pot condensation of 4-hydroxy-2H-chromen-2-one, isatin, and 1H-indazole-3-amine, in the presence of acetic acid in EtOH. This method has the advantages of operational simplicity, and high yield of products via a simple experimental and work-up procedure as compared to the conventional methods. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.     

Syntheses of spiro[indazole-3,3′-indolin]-2′-ones and spiro[indazole-3,3′-indolin]-2′-imines via 1,3-dipolar cycloadditions of arynes and studies on their isomerization reactions

A 1,3-dipolar cycloaddition reaction of arynes with 3-diazoindolin-2-ones under mild conditions in excellent yields has been developed, which allows facile access to a library of labile spiro[indazole-3,3′-indolin]-2′-ones. Spiro[indazole-3,3′-indolin]-2′-imines could be obtained as well following the same protocol. The isomerization reaction of spiro[indazole-3,3′-indolin]-2′-ones under thermal or acidic conditions has been efficiently achieved to afford a wide range of indazolo-[2,3-c]quinazolin-6(5H)-ones and the one-pot synthesis of indazolo-[2,3-c]quinazolin-6(5H)-ones from arynes and 3-diazoindolin-2-ones is also described. Whereas, spiro[indazole-3,3′-indolin]-2′-imines could not undergo the same rearrangement.     

Immobilized sulfonic acid functionalized ionic liquid on magnetic cellulose as a novel catalyst for the synthesis of triazolo[4,3-a]pyrimidines

The Brønsted acidic ionic liquid 1-(propyl-3-sulfonate) vinyl imidazolium hydrogen sulfate [IL] was supported on modified magnetic cellulose. The physical structure, composition, and functional groups of the novel supported ionic liquid catalyst were characterized via XRD, FT-IR, EDS, SEM, VSM, TGA, TEM, and BET techniques. Owing to the combination of nano-support features and flexible imidazolium linkers, it acted as a “quasi-homogeneous” catalyst to catalyze the preparation of triazolo[4,3-a]pyrimidine derivatives by a one-pot three-component reaction of active methylene compounds (ethyl cyanoacetate or malononitrile), aminotriazole and aryl aldehydes. The catalyst shows good catalytic activity for the synthesis of triazolo pyrimidines after six times of recycling.     

Montmorillonite K-10 clay catalyzed solvent-free synthesis of bis-indolylindane-1,3-dione, 2-(1′,3′-dihydro-1H-[2,3′]biindolyl-2′-ylidene)-indan-1,3-dione and bisindolylindeno[1,2-b]quinoxaline under microwave irradiation

An environmentally benign protocol has been described for the synthesis of novel 2-(1′,3′-dihydro-1H-[2,3′]biindolyl-2′-ylidene)-indan-1,3-diones/bis-indolylindane-1,3-diones from ninhydrin and 3-substituted/unsubstituted indoles. It uses montmorillonite K-10 as catalyst in a solvent-free condition under microwave irradiation. The method was also used for the synthesis of novel bisindolylindeno[1,2-b]quinoxaline derivatives.     

Synthesis of [1,2,3]Triazolo[5,1-a]isoquinoline Derivatives via a Selective Cascade Cyclization Sequence of 1,2-bis(Phenylethynyl)benzene Derivatives

A direct, concise, synthetic method for the generation of [1,2,3]triazolo[5,1-a]isoquinoline derivatives, using a selective cascade cyclization of unsymmetrical substituted 1,2-bis(phenylethynyl)benzene derivatives with NaN₃, has been developed. The reaction gave different substituted [1,2,3]triazolo[5,1-a]isoquinolines in moderate to good yields. It was found that the substituents on the alkynes were important for the selectivities of the cascade cyclization sequences.     

An expedient approach to substituted triazolo[1,5-a][1,4]benzodiazepines via Cu-catalyzed tandem Ullmann C–N coupling/azide-alkyne cycloaddition

An approach to the synthesis of triazolo[1,5-a][1,4]benzodiazepines comprising copper catalyzed tandem Ullmann C–N coupling followed by azide-alkyne cycloaddition has been described. The reaction of o-azidobenzylbromide and N-propargylated aniline derivatives in the presence of CuI and base leads to the formation of triazolo[1,5-a][1,4]benzodiazepines. The reaction has been successfully generalized by synthesizing a number of triazolo[1,5-a][1,4]benzodiazepine derivatives in good to excellent yields.     

N,N-Dichlorobis(2,4,6-trichlorophenyl)urea (CC-2) as a new reagent for the synthesis of pyrimidone and pyrimidine derivatives via Biginelli reaction

A simple and efficient method for the synthesis of 3,4-dihydropyrimidin-2-(1H)one and benzo[4,5]imidazo/thioazo[1,2-a]pyrimidine derivatives has been described using N,N′-dichlorobis(2,4,6-trichlorophenyl)urea (CC-2) as a new reagent. This method is found to be efficient and convenient for the synthesis of pyrimidone and pyrimidine derivatives.     

3,5-Disubstituted 6H-pyrrolo[1,2-c][1,2,3]triazoles from Morita-Baylis-Hillman adducts of propargyl aldehydes

A simple method for synthesizing several 6H-pyrrolo[1,2-c][1,2,3]triazole derivatives having a methoxycarbonyl or an acetyl group at C-5 position and 7,8-dihydro-4H-[1,2,3]triazolo[1,5-a]indol-5(6H)-ones via an intramolecular 1,3-dipolar cycloaddition reaction of azido enynes, which were readily obtained from the Morita-Baylis-Hillman acetates of propargyl aldehydes with sodium azide, has been developed.     

One-pot chemoselective synthesis of novel fused pyrimidine derivatives

One-pot triple-component reaction of 4-hydroxycoumarin with aromatic aldehydes and 2-aminobenzimidazole, 3-amino-1H-1,2,4-triazole, or 6-aminouracil in acetonitrile in the presence of catalytic amounts of sulfamic acid led to a chemoselective synthesis of chromeno[4,3-d]pyrimidine-6-one, triazolo[1,5-a]pyrimidin-5-one, and pyrido[2,3-d]-pyrimidine-2,4,7-trione derivatives, respectively, in good yields.     

Synthesis of diverse benzo[1,4]oxazin-3-one-based compounds using 1,5-difluoro-2,4-dinitrobenzene

This paper discusses the synthesis of benzo[1,4]oxazin-3-one-based compounds from 1,5-difluoro-2,4-dinitrobenzene (1), including benzo[1,4]oxazin-3-ones (5-11) and five novel benzo[1,4]oxazin-3-one-based tricycles: 6-hydroxy-4H-1-oxa-4,5,8-triazaanthracen-3-one (14), 3,8-dihydro-5-oxa-1,3,8-triazacyclopenta-[b]-naphthalene-7-one (15, 17, 21), 3,8-dihydro-5-oxa-1,2,3,8-tetraazacylopenta[b]-naphthalene-7-one (16, 20), 3,8-dihydro-1H-5-oxa-1,3,8-triazacyclopenta[b]-naphthalene-2,7-dione (18, 22), and 5,8-dihydro-4H-1-oxa-4,5,8-triazaanthracene-3,6,7-trione (19). Finally, a chemical library based on 15 was synthesized in parallel solution-phase reactions.     

A facile,catalyst-free synthesis of new polycyclic pyrrolo[1,2-b]pyrazolone derivatives

A convenient and efficient procedure has been developed for the synthesis of a new ring system, pyrrolo[1,2-b]pyrazolone, via two-component coupling reaction followed by base mediated intramolecular cyclization. Single-pot synthesis replacing the two step process has also been successfully carried out. A series of polycyclic pyrrolo[1,2-b]pyrazolone derivatives have been obtained by employing the procedure along with some fused pyrrol-1-ylamine system. The products were formed very rapidly in catalyst free condition in a good yield (up to 75%) and also it had tolerance to a wide scope of substrates.     

A novel and efficient synthesis of pyrimido[4,5-d]pyrimidine-2,4,7-trione and pyrido[2,3-d:6,5-d] dipyrimidine-2,4,6,8-tetrone derivatives

An efficient and direct procedure for the synthesis of pyrimido[4,5-d]pyrimidine-2,4,7-trione derivatives has been described under microwave-assisted conditions. Reaction of 6-amino-1,3-dimethyluracil with aromatic aldehydes resulted in the formation of pyrido[2,3-d:6,5-d] dipyrimidine-2,4,6,8-tetrone derivatives.     

Poly(4-vinylpyridinium) hydrogensulfate catalyzed synthesis of 12-aryl-12H-indeno[1,2-b]naphtho[3,2-e]pyran-5,11,13-triones

A simple and facile synthesis of 12-aryl-12H-indeno[1,2-b]naphtho[3,2-e]pyran-5,11,13-trione derivatives was accomplished via the one-pot condensation of 2-hydroxynaphthalene-1,4-dione, aldehydes, and 2H-indene-1,3-dione at 100 °C under solvent-free conditions in the presence of the solid acid catalyst, poly(4-vinylpyridinium) hydrogensulfate. This method has the advantages of high yields, clean reactions, simple methodology, and short reaction times. The catalyst could be recycled and reused four times without significant loss of activity. The structures of the novel compounds were confirmed by IR, ¹H NMR, and elemental analysis.     

Simple and efficient preparation of 3-substituted 6-(4-chlorophenyl)-9-methyl-12H-[1]benzofuro[3,2-e][1,2,4]triazolo[4,3-b][1,2]diazepines via a silylation–amination reaction

Abstract  

A series of new 3-substituted 6-(4-chlorophenyl)-9-methyl-12H-[1]benzofuro[3,2-e][1,2,4]triazolo[4,3-b][1,2]diazepines was synthesized from the corresponding bicyclic 1-(4-chlorophenyl)-3,5-dihydro-8-methyl-4H-[1]benzofuro[2,3-d][1,2]diazepin-4-one. The synthesis strategy makes use of silylation–amination as the key step, allowing a wide range of derivatives to be prepared.     

Ultrasound-assisted synthesis of pyrazolo[1,2-<Emphasis Type="Italic">b</Emphasis>]phthalazines and dihydrospiro[indoline-3,1'-pyrazolo[1,2-<Emphasis Type="Italic">b</Emphasis>]phthalazines] using TBAF as an efficient phase-transfer catalyst

Tetrabutylammonim fluoride has been used as an efficient catalyst for synthesis of pyrazolo[1,2-b]-phthalazine-5,10-diones and dihydrospiro[indoline-3,1'-pyrazolo[1,2-b]phthalazines] by one-pot three-component reaction of phthalhydrazide, aromatic aldehydes or isatin derivatives, with malononitrile in water under ultrasond irradiation. This rapid method gave the products in high yield.