MK-10 Clay–Catalyzed Synthesis of 2-(2′,5′-Disubstituted-1′H-indol-3′-yl)-1H-benzo[d]imidazoles under Conventional and Microwave Irradiation

The synthesis of benzimidazoles has been achieved in a one-pot reaction in excellent yield using a newly developed methodology. 2,5-Disubstituted-3-cyanoacetyl indoles were directly condensed with substituted orthophenylenediamine via microwave irradiation under neat, solid support, and conventional conditions in a short time to afford the corresponding products in good yields. Structures of the products thus obtained were confirmed by their melting points, infrared, ¹H NMR, ¹³C NMR, and mass spectral data.

Facile Synthesis of 2-(4-Hydroxybiphenyl-3-yl)-1H-indoles from Anilines and 5′-Bromo-2′-hydroxyacetophenone

2-Arylindoles are attractive scaffolds because they are found in many pharmacologically active molecules. In this study, we describe the facile synthesis of diverse 2-(2-hydroxyphenyl)-1H-indoles from anilines and 5′-bromo-2′-hydroxyacetophenone in two steps using palladium-catalyzed indole cyclization as a key reaction. The indole cyclization was primarily controlled by the substituent properties of anilines. Suzuki-coupling reactions of 2-(5′-bromo-2′-hydroxyphenyl)-1H-indoles with arylboronic acids provided the corresponding 2-(4-hydroxybiphenyl-3-yl)-1H-indoles in moderate yield.     

Synthesis of 2-(9H-carbazol-1-yl)anilines from 2,3′-biindolyl and ketones

Twenty-nine examples of 2-(9H-carbazol-1-yl)anilines were obtained in yields from 27 to 95% by refluxing 2,3′-biindolyl (1 equiv.) and ketones (1 equiv.) in ethanolic HCl. Alkyl, cyclic, and aryl ketones were found to be compatible with this method, however, aldehydes are not. Because the reaction proceeds by addition of the carbonyl C atom to the biindolyl 3-position, this method has high regioselectivity. One example is presented of bridging the two N atoms in the carbazolylaniline product with an acetaldehyde synthon to give a benzodiazepino[lm]carbazole. Also, one example is given of installing a dimethylamino group at the α-position of the starting ketone to give an indolo[3,2-c]carbazole.     

One-Pot Synthesis of 3,4-Dihydropyrimidine-2-(1H)-ones Using CsF–Celite as Catalyst

A facile, efficient, and environmentally benign procedure for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones via the cyclocondensation reaction of aromatic aldehyde, ethyl acetoaceate, and urea catalyzed by CsF–Celite was developed. This environmentally friendly method is superior to previous methods with respect to reaction time, yield, and workup.     

An efficient one pot–three component cyclocondensation in the synthesis of 2-(2-chloroquinolin-3-yl)-2,3-dihydroquinazolin-4(1H)-ones: potential antitumor agents

Montmorillonite K10 efficiently catalyzed a one pot–three component cyclocondensation of isatoic anhydride, NH₄OAc and aromatic/heteroaromatic aldehydes under ambient conditions to produce the corresponding 2-substituted-2,3-dihydroquinazolin-4(1H)-ones in good yields. The 2-(2-chloroquinolin-3-yl)-2,3-dihydroquinazolin-4(1H)-ones 3a–d were screened for their antitumor activity against Ehrlich Ascites Carcinoma tumor cells     

Investigations in the region of 2,3′-biquinoline. 3. Synthesis of 2′-alkyl(aryl)-1′,2′-dihydro-2,3′-biquinolines and 2′-alkyl(aryl)-2,3′-biquinolines

A method was developed for the synthesis of 2-alkyl(aryl)-1,2-dihydro-2,3-biquinolines, based on the addition of organolithium compounds to 2,3-biquinoline in the presence of tetramethylethylenediamine. Their oxidation with manganese dioxide led to 2-alkyl(aryl)-2,3-biquinolines.For Communication 2, see [1].Stavropol State University, Stavropol 355009, Russia. Russian Chemical-Technology University, Moscow 125190. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 350–354, March, 1998.     

SbCl3-catalyzed solvent-free Friedel–Crafts reaction of phenols with mandelic acids to 3-aryl benzofuran-2(3H)-ones: Synthesis of spirocyclic 2,3-dihydrobenzofuran-2-ones

A facile, SbCl₃-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally, the utility of 3-aryl benzofuran-2(3H)-ones is demonstrated by using them as precursors in the synthesis of a new class of spirocyclic benzofuran-2-ones using classical synthetic methodologies.     

Synthesis of novel spiro[indole-3,3′-pyrrolidin]-2(1H)-ones

Diastereoselective [3+2] cycloaddition of azomethine ylide to 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5-e]thiazolo[3,2-b]-[1,2,4]triazine-2,7(1H,6H)-dione yields hitherto unknown 1,1′,3-trimethyl-3a,9a-diphenyl-3,3a,9,9a-tetrahydrodispiro(imidazo[4,5-e]thiazolo[3,2-b][1,2,4]triazine-6,3′-pyrrolidine-4′,3″-indole)-2,2″,7(1H,1″H)-triones.     

Synthesis and Characterization of 4′-Bromomethyl-2-(N-trityl-1H-tetrazol-5-yl) Biphenyl

Biphenyl tetrazole ring is an important component of the Sartan family of novel drugs. 4′-Bromomethyl-2-(N-trityl-1H-tetrazol-5-yl)biphenyl was synthesized in this article from 4′-methyl-2-cyano-biphenyl through three steps. 4′-Methyl-2-cyano-biphenyl was reacted with azide ions with the help of ammonium chloride as catalyst in an autoclave with high conversion to afford the tetrazole compounds in 70.6% yield. After being protected by the trityl group with 92.6% yield, 4′-methyl-2-(N-trityl-1H-tetrazol-5-yl) biphenyl was brominated with N-bromosuccinimide (NBS) in cyclohexane with 2,2′-azo-isobutyronitrile (AIBN) acting as an initiator to provide the title compound in 83.8% yield.     

Synthesis of 5-substituted-3-[(2′S,3′S)-3′-hydroxy-2′-hydroxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazoles and their epimers

5-Phenyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10a and its epimer 11a, 5-methyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10b and its epimer 11b were synthesized from cyanohydrin benzoates 8a, 9a and cyanohydrin acetates 8b, 9b, respectively, by treatment with hydroxylamine in methanol via intramolecular transacylation and subsequent cyclization of the corresponding amidoximes. Hydrolysis and reduction of the dimethoxymethyl groups in the above compounds gave the desired compounds 12a, 13a, 12b and 13b.     

Facile and Efficient Regioselective Synthesis of 1-(3′-Substituted Quinoxalin-2′-yl)-3-aryl/heteroaryl-5-methylpyrazoles

This report describes an efficient and practical approach for regioselective synthesis of 1-(3′-substituted quinoxalin-2′-yl)-3-aryl/heteroaryl-5-methylpyrazoles (3a–j). Reaction of 2-chloro-3-substituted quinoxalines (1) with 3(5)-methyl-5(3)-aryl-1H-pyrazoles (2) in the presence of sodium hydride furnished the title compounds in excellent yields with good levels of regioselectivity. The present protocol is superior to the existing method, which yielded a mixture of regioisomeric pyrazoles (I, II) and triazolo[4,3-a]quinoxalines (III).

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis and characterization of transition metal complexes of N′-[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene]thiophene-2-carbohydrazide

A hydrazone ligand (HL) containing the thiophene moiety has been prepared via condensation of thiophene-2-carbohydrazide with 1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carbaldehyde. The complexes of copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), palladium(II), iron(III), ruthenium(III), uranyl(VI), and titanium(IV) with the ligand were prepared in good yield from the reaction of the ligand with the corresponding metal salts. The ligand and complexes were characterized using infrared, mass spectra, nuclear magnetic resonance, electronic absorption spectra, electron spin resonance, and magnetic moment measurements as well as elemental and thermal analyses. The results showed that the complexes are enolic by nature, whilst the ratio between the metal ion and the ligand depends on the acidity of the metallic ions and their oxidation numbers.     

A Brønsted Acid Catalyzed Cascade Reaction for the Conversion of Indoles to α-(3-Indolyl) Ketones by Using 2-Benzyloxy Aldehydes

A Brønsted acid catalyzed, operationally simple, scalable route to several functionalized α-(3-indolyl) ketones has been developed and the long-standing regioisomeric issue has been eliminated by choosing appropriate carbonyls. A readily available and cheap bottle reagent was used as the catalyst. This protocol was also applicable to the synthesis of densely functionalized α-(3-pyrrolyl) ketones. A detailed mechanistic study confirmed the involvement of enolether as a reaction intermediate. Several postsynthetic modifications along with easy access to β-carboline, tryptamines, tryptophols, and spiro-indolenine proclaim the synthetic utility of this powerful building block. On the basis of this concept, functionalized carbazoles were constructed by a cascade annulation strategy.     

Facile Synthesis of 3,3-Di(1H-indol-3-yl)indolin-2-ones Catalyzed by Ceric Ammonium Nitrate (CAN) under Ultrasound Irradiation

Indole fragment is featured widely in a wide variety of pharmacologically and biologically active compounds.[1] The 3,3-bis(3-indolyl)oxindole has been shown to possess antibiotic activities against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. [2] As a continue of our work on the synthesis of indole derivates such as bis(indolyl)methanes,[3]we describe an ultrasound-accelerated reaction of isatin 1 with indoles 2 using a catalytic amount of ceric ammonium nitrate (CAN), which provides an efficient route to the synthesis of 3,3-di(1H-indol-3-yl)indolin-2-ones.     

Synthesis of 1′,3′-Dioxolan-2′-one by the Reaction of Steroidal Oxiranes with Carbon Dioxide: Synthesis of Five-Membered Cis Cyclic Carbonates

The reaction of 3β-acetoxy-5,6α-epoxy-5α-cholestane 1, its 3β-chloro analogue 2, and 5,6α-epoxy-5α-cholestane 3 with carbon dioxide gas in the presence of sodium bromide as catalyst with continuous stirring at 100 °C for 30 min affords selectively the corresponding 1′,3′,-dioxolan-2′-ones (steroidal cyclic cis-carbonates) 4–6 in excellent yields. The structures of these products have been established on the basis of their elemental analysis and spectral data (infrared, ¹H NMR, and mass).     

Synthesis and crystal structures of three new complexes derived from 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole

Three new coordination complexes, [Cd₂(ppt)₂(cpba)]?·?(H₂O)₂ (1), [Zn(ppt)₂]?·?(H₂O) (2), and [Zn(MoO₄)(Hppt)] (3) (H₂cpba: 3-(2′-carboxy-phenoxy)-benzoic acid; Hppt: 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole), were synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. X-ray diffraction analyses revealed that Cd(II) ions are linked by ppt^? to form a ladder-shaped structure along the a-axis and further displays a 2-D supramolecular architecture with cpba^2? along the c-axis. In 2, each Zn(ppt)₂ fragment is linked by the nitrogen of pyridin-3′-yl from the neighboring Zn(ppt)₂ forming a V-shaped chain. Compound 3 consists of a ladder structure, in which each {MoO₄} unit is a bridge linking three Zn(Hppt)²⁺ fragments.     

An efficient,catalyst free synthesis of 3-(2′'-benzothiazolyl)-2,3-dihydroquinazolin-4(1H)-ones in aqueous medium

Abstract

An efficient and environmentally benign protocol for the synthesis of 3-(2′-benzothiazolyl)-2,3-dihydroquinazolin-4(1H)-ones has been developed. The synthesis of these pharmacologically important compounds can be achieved by the three component condensation of isatoic/5-chloroisatoic anhydride, aldehyde, and 2-aminobenzothiazole in water: ethanol (1:1, v/v) without the aid of any catalyst.

Synthesis of N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]-methylenediamine derivatives

[3+2] Cycloaddition of azide groups of N,N′-bis(4-azidofurazan-3-yl)methylenediamine to 1,3-dicarbonyl compounds and malonodinitrile was shown to proceed regioselectively with the formation of the corresponding N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]methylenediamine derivatives. The reactions of N,N′-bis(4-azidofurazan-3-yl)methylenediamine with cyanoacetic acid ethyl ester and amide led to the formation of the product of transformation of the azide group in the starting compound to the amino groups.     

Samarium Triflate–Catalyzed Biginelli Condensation: An Improved Method for the Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

Abstract

A simple and efficient method for multicomponant synthesis of 3,4-dihydropyrimidinones has been reported. All the reactions were carried out using samarium triflate as catalyst (10 mol%) at acetonitrile reflux. This procedure is applicable to a variety of substrates such as aliphatic, aromatic, and heterocyclic aldehydes.

Synthesis of 3-(2-(4-Chlorophenylimino)-3-(4-chlorophenyl)-2,3-dihydrothiazol-4-yl)-2 h-Chromen-2-one via Multicomponent Approach

A simple and highly efficient one-pot, three-component synthesis of 3-(2-(4-chlorophenylimino)-3-(4-chlorophenyl)-2,3-dihydrothiazol-4-yl)-2H-chromen-2-ones has been reported by the reaction of 3-(2-bromoacetyl)-2H-chromen-2-one, primary amines, and phenyl isothiocyanates in presence of dimethylformamide as a solvent. The structures of newly synthesized compounds were confirmed by their analytical and spectral data.