Rapid and Efficient Synthesis of 3,3-Di(1H-indol-3-yl)indolin-2-ones and 2,2-Di(1H-indol-3-yl)-2H-acenaphthen-1-ones Catalyzed by p-TSA

An efficient synthesis of 3,3-di(1H-indol-3-yl)indolin-2-ones and 2,2-di(1H-indol-3-yl)-2H-acenaphthen-1-ones via a reaction of various isatins or acenaphthenequinone with indoles in the presence of p-methylbenzene sulfonic acid (p-TSA) in CH₂Cl₂ at room temperature is described. The advantages of this method include good reaction yield, simple workup procedure, and mild reaction condition.     

General synthesis of mono-, di-, and tri-acetylated indoles from indolin-2-ones

Having developed the one-pot triacetylation of indolin-3-ones, we have now devised a simple two-step reaction sequences to produce di- and mono-acetylated indoles from indolin-2-ones. The indolin-2-ones were first subjected to acetylation in the presence of acetic anhydride and a catalytic amount of N,N-dimethylaminopyridine to give 2-acetoxy-1,3-diacetylindoles. Subsequently, an enzyme-assisted deacetylation resulted in the chemoselective deprotection of the acetoxy group to produce 1,3-diacetyl-2-hydroxyindoles. However, a chemical deacetylation of 2-acetoxy-1,3-diacetylinoles under mild basic or acidic conditions resulted in the formation of 3-acetyl-2-hydroxyindoles.     

Stereoselective synthesis of 3-alkylidene/alkylazetidin-2-ones from azetidin-2,3-diones

Azetidin-2,3-diones have been used as synthons for the synthesis of C-3 alkylidene/alkylazetidin-2-ones. Some of the 3-alkylazetidin-2-ones are well known for their cholesterol absorption inhibitor activity. A regio and stereoselective Grignard reaction on a keto group followed by dehydration using PPh₃/CCl₄ reagent is a key step in this synthesis. Hydrogenation of the 3-alkylideneazetidin-2-ones provided stereoselectively cis-3-alkylazetidin-2-ones in very good yields.     

Michael condensation of 3-arylidene-3H-pyrrol-2-ones and 3-arylidene-3H-furan-2-ones with cyclohexanone

The Michael condensation in the series of 5-aryl-3-arylidene-3H-pyrrol-2-ones and 5-aryl-3-arylidene-3H-furan-2-ones, containing an activated C=C bond, with cyclohexanone was investigated. It was shown that the condensation products were 1,5-dicarbonyl compounds containing a heterocyclic fragment. The enolization of one of the oxo groups, leading to the formation of hydroxypyrrole or hydroxyfuran structures, was demonstrated by the spectral data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 2007.     

HFIP-promoted catalyst-free cascade reactions for the synthesis of biologically relevant 3,3-di(indolyl)indolin-2-ones from indoles and isatins

The first HFIP-promoted catalyst-free cascade reactions for the synthesis of biologically relevant 3,3-di(indolyl)indolin-2-ones (27 examples, up to 98% yield) from readily available indoles and isatin derivatives are described. This protocol shows well tolerance of different functional groups and features mild reaction conditions such as short reaction time (∼ 1 h), no usage of catalyst, easy operation and product isolation. Of particular interest is the formation of two CC bonds and one all-carbon quaternary center. This protocol could serve as an alternative strategy to synthesize biologically important 3,3-di(indolyl)indolin-2-ones for biological testing.     

Ultrasound-assisted synthesis of 3-(1-(2-(1H-indol-3-yl)ethyl)-2-aryl-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indol-3-yl)indolin-2-ones by novel core-shell bio-based nanocatalyst anchoring sulfonated L-histidine on magnetized silica (SO3H-L-His@SiO2-nano Fe3O4)

An efficient synthesis of 3-(1-(2-(1H-indol-3-yl)ethyl)-2-aryl-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indol-3-yl)indolin-2-ones is reported via a one-pot three-component reaction of 3-phenacylidenoxindoles, tryptamine, and dimedone under ultrasound irradiation using a newly prepared core-shell nanostructure. The utilized nanocatalyst is obtained by anchoring sulfonated L-histidine amino acid shell, as the bio part, on silica-nanomagnetite core (SO₃H-L-His@SiO₂-nano Fe₃O₄) and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (¹H NMR), field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric/differential thermal analysis, vibrating sample magnetometer measurements, transmission electron microscopy, and back-titration. The protocol contains several advantages, such as relatively short reaction times, simple work-up procedure by separation of the catalyst with an external magnet, the use of economical and environmentally friendly ultrasonic waves, and reusability and recoverability of the core-shell nano-promoter for three runs without significant activity loss.     

Facile synthesis of 2-carboxanilido-3-arylquinazolin-4-ones from N1-(2-carboxyphenyl)-N2-(aryl)oxalamides

A simple and efficient approach for the synthesis of novel 2-carboxanilido-3-arylquinazolin-4-ones via the one-pot condensation of readily available N¹-(2-carboxyphenyl)-N²-(aryl)oxalamides with various aromatic amines is described. Notably, this methodology allows us to synthesize 3-aryl-quinazolin-4-ones using aromatic amines with various substituents, both electron-donating and electron-withdrawing, which ensures structural diversity of the products and an atomic-economic process.     

Toward understanding the scope of Baylis-Hillman reaction: synthesis of 3-(2- hydroxyphenyl)indolin-2-ones and polycyclic fused furans

A facile one-pot synthesis of 3-(2-hydroxyphenyl)indolin-2-ones has been developed via the TiCl₄-mediated Baylis-Hillman (B-H) reaction of N-substituted isatins and cyclohex-2-enone, followed by treatment of the in situ generated B-H alcohols with aq HBr. Baylis-Hillman reaction of aromatic cyclic 1,2-diones with cycloalk-2-enones under the influence of TiCl₄ has been successfully performed and the resulting Baylis-Hillman adducts have been conveniently transformed into pentacyclic and hexacyclic fused furan derivatives.     

Convenient synthesis of 3-aminomethylenedihydrofuran-2-ones

A simple and convenient synthesis of a series of 3-aminomethylenedihydrofuran-2-ones from the reaction of 3-trichloroacetyl-4,5-dihydrofuran with amines, is presented.     

B(C6F5)3-Catalyzed Aza-Friedel–Crafts Reaction of Indolizines with 2-Aryl-3H-indol-3-ones

A Friedel–Crafts reaction of indolizines with 2-aryl-3H-indol-3-ones catalyzed by B(C₆F₅)₃ is described. This protocol gives access to indolizine derivatives that are valuable building blocks in synthetic and pharmaceutical chemistry. The reaction proceeds under mild conditions, affording various C2-quaternary indolin-3-ones based on indolizine with high yields and regioselectivities. Moreover, the synthetic transformations of the target products were realized by N-methylation and trifluoromethane sulfonation.     

Bromination of 5-Substituted 3H-Furan-2-ones and 3H-Pyrrol-2-ones

The bromination of 5-alkyl(aryl)-3H-furan-2-ones and 5-alkyl(aryl)-3H-pyrrol-2-ones and also their derivatives takes place at the ethylene bond with the formation of 4-monobromo derivatives. N-Phenyl-3H-pyrrol-2-ones are brominated simultaneously at the ethylene bond of the heterocycle and at the phenyl substituent at the nitrogen atom.     

Dehydration of 4-hydroxy-4-methyl-3-phenylamino-oxazolidin-2-ones

The dehydration of two 5,5-disubstituted 4-hydroxy-4-methyl-3-phenylaminooxazolidin-2-ones into the corresponding 4-methylene-3-phenylaminooxazolidin-2-ones has been carried out. The structure of the products was confirmed by X-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1512–1517, October, 2004.     

Preparation and alkylation of regioisomeric tetrahydrophthalimide-substituted indolin-2(3H)-ones

A series of novel regioisomeric tetrahydrophthalimide-substituted indolin-2-ones has been prepared via the Sommelet-Hauser type cyclization of appropriately substituted anilines as potential herbicides. The resultant indolin-2-ones were then regioselectively alkylated at N-1 and C-3 to give 1,3,3-trisubstituted indolin-2-ones. The most active series was also prepared by the bis-nitration of m-fluorophenylacetic acid followed by reduction and cyclization to give 6-amino-5-fluoroindolin-2-one. Elaboration to the tetrahydrophthalimide-substituted indolin-2-one was followed by C- and N-alkylation to give the desired compounds.     

Phase-transfer catalysis in reactions of 5-alkyl-3H-furan-2-ones with dichlorocarbene

Treatment of 5-alkyl-3H-furan-2-ones and 5-alkyl-3H-thiophen-2-ones with dichlorocarbene under conditions of phase-transfer catalysis at 20–90 °C results in insertion of the carbene at the C=C bond followed by skeletal rearrangement.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1995–1997, October, 1995.     

Arylmethylene derivatives of 5-R-3H-furan-2-ones and N-aryl-5-R-3H-pyrrol-2-ones in reaction with acetylacetone

Reaction with acetylacetone in the series of 3-arylmethylene-substituted furan-2-ones and pyrrol-2-ones was studied. 8-R-4-Acyl-5-aryl-3-oxo-9-oxabicyclo[4.3.0]nona-1,7-dienes and N-tolyl-8-R-4-acyl-5-aryl-3-oxo-9-azabicyclo[4.3.0]nona-1,7-dienes were synthesized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1457–1462, October, 2007.     

Cycloacylation of 3-oxo-3-R1-N-R2-propanethioamides by 3-aryl-2-propenoyl chlorides

The products of cyclocondensation of 3-oxo-3-R¹-N-R²-propanethioamides with 3-aryl-2-propenoyl chlorides in acetone in the presence of potassium carbonate are 5-acyl-1-aryl(alkyl)-4-aryl-6-thioxopiperidin-2-ones, 5-acyl-2-aryl-6-aryl(alkyl)amino-2,3-dihydro-4H-thiopyran-4-ones, and 2-acetonylidene-3,6-diaryl-5,6-dihydro-4H-1,3-thiazin-4-ones, the structure of which is proven by both spectral methods and chemical conversions. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 623–628, April, 2006     

1-Oxa-3-azapentalen-2-ones as Precursors of cis-2-Amino Alcohols: Synthesis from Propargyl Alcohols, CO2, and Amines Using an Intramolecular Amidoalkylation Reaction of Oxazolidin-2-ones

The reaction of 5-methyl-5-(4-methyl-3-pentenyl)-4-methylene-1,3-dioxolan-2-one with primary amines gives the corresponding 4-hydroxy-4-methyloxazolidin-2-ones. These undergo an intramolecular amidoalkylation reaction to form 1-oxa-3-azapentalen-2-ones which are potential precursors of cyclopentanyl cis-2-amino alcohols.     

Highly efficient one-pot C-, N- and O-acylation of indolin-2-one analogs

A highly efficient one-pot multiple acylation at chemically non-equivalent sites on indolin-2-one and related motifs using 4-(N,N-dimethylamino)pyridine as a catalyst is described. This procedure gives extremely facile entry to highly desired 3-acyl-2-hydroxy-indole synthons among other derivatives.     

Synthesis of 3-Arylquinoxalin-2(1H)-ones under Visible-Light Irradiation with Oxygen-Doped Carbon Nitride as Heterogenous Photocatalyst

A novel oxygen-doped graphitic carbon nitride (OCN) material was designed and synthesized via the hydrothermal-calcination method with melamine and hydroperoxide as starting materials. The OCN material was utilized as a highly efficient solid metal-free photocatalyst for the synthesis of 3-arylquinoxalin-2(1H)-ones via the catalytic decomposition of aryl diazonium salts under blue light irradiation. Following this approach, various 3-arylquinoxalin-2(1H)-one derivatives could be obtained in moderate to excellent yields with broad substrate scope under mild conditions. Also, the OCN solid photocatalyst shows good recyclability in the reaction, there was no appreciable loss in yields observed even after 5 cycles. This methodology offers a practical, mild, and metal-free alternative to the preparation of 3-arylquinoxalin-2(1H)-ones.     

An efficient synthesis of 3-(indol-3-yl)quinoxalin-2-ones with TfOH-catalyzed Friedel-Crafts type coupling reaction in air

An efficient one-pot synthetic approach to access a variety of 3-(indol-3-yl)quinoxalin-2-ones from various quinoxalin-2-ones and very wide scope of indoles through TfOH-catalyzed Friedel-Crafts type coupling reaction in DMF has been developed. Only 10 mol % Brønsted acid as a catalyst, air as an oxidizer, and very wide range of substrates are the prominent advantages of this method.