Reaction of Some Indoles with 1,4‐Naphthoquinones in the Presence of Pd(OAc)2

The reaction available for the introduction of an indole unit into the 1,4‐naphthoquinone skeleton is described. The reaction of the indoles with 1,4‐naphthoquinones in CH₃CN in the presence of Pd(OAc)₂ gave the corresponding 2‐(3‐indolyl)‐1,4‐naphthoquinones in moderate yield.     

Syntheses of functionalized 1,4-disubstituted gamma-carbolines

We report the complete synthesis of a variety of 1,4-disubstituted gamma-carbolines. These compounds are of particular interest for their involvement in many biological processes and are believed to possess various medicinal activities. A large number of N-tosylaldimines were condensed with indoles affording an array of 3-aminomethyl indoles. Subsequent additions, followed by intramolecular cyclization, afforded an array of 1,2-dihydro-3H-gamma-carbolones in good yield. Upon subsequent aromatization, the corresponding fully aromatic functionalized 1-aryl-4-hydroxy-gamma-carbolines resulted.     

Novel photoisomerization of 5-chloro-1,4-dihydro-9-methyl-naphthalen-1,4-imine

Direct photolysis of 5-chloro-1,4-dihydro-9-methyl-naphthalen-1,4-imine in cyclohexane gave a mixture of 1-chloronaphthalene and isomeric dihydrocyclobut[b]indoles $\text{5}$ and $\text{6}$. Dihydrocyclobut[b]indoles $\text{5}$ and $\text{6}$ thermally rearranged to give 1-benzazepines $\text{7}$ and $\text{8}$, respectively.     

Catalytic hydrogenation of 1,4-phenylenediamine to 1,4-cyclohexanediamine

Catalytic hydrogenation of 1,4-phenylenediamine to 1,4-cyclohexanediamine using Ru/Al₂O₃ as a catalyst was carried out in water, and the results were compared with those in isopropanol and SC-CO₂. 80% 1,4-phenylenediamine conversion with 87% selectivity to 1,4-cyclohexanediamine was achieved on 5% Ru/Al₂O₃ catalyst at 90°C and H₂ pressure of 4 MPa. The hydrogenation of 1,4-phenylenediamine is influenced by the solvent. A systematic study of the hydrogenation of 1,4-phenylenediamine revealed that the reaction was consecutive. The longer the time, the lower was the CHDA selectivity. Also, the reaction temperature was an important parameter and played a vital role in preventing the formation of side products.     

A convergent construction of 1,4-dihydropyridine scaffold containing indole fragment

Accompanying with the construction of 1,4-dihydropyridine scaffold, indol-3-yl-5-oxo-1,4,5,6,7,8-hexahydroquinoline, and indol-3-yl-1,4-dihydropyridine derivatives were facilely synthesized through three-component reactions of aromatic aldehydes, 3-cyanoacetyl indoles with 3-amino-2-enones in the presence of ammonium acetate. The 1,4-dihydropyridine core structure can be efficiently aromatized in the presence of stoichiometric 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). This chemistry provides an efficient and promising synthetic strategy to diversity-oriented construction of unaromatized and aromatized desired products. The advantages of the present protocol are atom-economy, simple work-up and easy purification of products by non-chromatographic methods.     

Novel ring transformation of quinolines to indole derivatives in two steps via 1,4-dihydroquinoline derivatives

Diphenyl 1-phenoxycarbonyl-1,4-dihydroquinoline-4-phosphonates 5c-g, obtained from the reaction of corresponding quinoline derivatives 1 with phenyl chloroformate and triphenyl phosphite in one step, were ozonized in CHCl₃ and CH₃COOH. Treatment of the resulting mixture with NaHCO₃ produced the 3-formyl-1-phenoxycarbonylindole derivatives 8a-e in high yields. The ring transformation of quinolines 1 to indoles 8 proceeds under mild conditions.     

Reactions of Substituted Indoles with 2,3-Dichloro-1,4-naphthoquinone and Electrochemical Properties of Some 2,3-Substituted 1,4-Naphthoquinones

Russian Journal of Organic Chemistry - The reactions of 2,3-dichloro-1,4-naphthoquinone with some indoles and thiols were investigated. The resulting nucleophilic substitution products were...     

Diastereoselective Ruthenium-Catalyzed Michael Addition of Indoles to Hormone Steroids: An Efficient Route to New Indole Derivatives

Diastereoselective conjugate 1,4-addition of indoles to α,β-unsaturated carbonyl compounds (hormone steroids) using Ru(III) as catalyst is reported. It was found that RuCl₃·nH₂O catalyzes the Michael addition of indoles to hormone steroids, providing new 3-alkylated derivatives in good to excellent yields.     

Synthesis of difunctional 1,4-dimethyl-1,4-disilacyclohexanes

Transformations of HVinSiCl₂, HVinSi(Me)Cl, HVinSi(Me)Ph, and HVinSi(Me)NEt₂ in the presence of Pt catalyst were studied. In dilute solutions, the reaction gave a mixture of structural and stereoisomers of five- and six-membered disilacyclanes, resulting from intramolecular cyclization of the initially formed linear dimer. In the case of methyl(phenyl)disilacyclane, the structural isomers were separated andtrans-1,4-dimethyl-1,4-diphenyl-1,4-disilacyclohexane was isolated. The reaction of this product with HCl in the presence of AlCl₃ followed by hydrolysis resulted in the synthesis oftrans-1,4-dichloro- andtrans-1,4-dihydroxy-1,4-dimethyl-1,4-disilacyclohexanes. The structures of the structural and stereoisomers synthesized were confirmed by¹H,¹³C, and²⁹Si NMR and IR spectroscopies and mass spectrometry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1734–1738, September, 1999.     

Zur Verwendbarkeit von 13C-Substituenteninkrementen bei 1,4-Benzo- und 1,4-Naphthochinonen

About the Availability of ¹³C-NMR Substituent Increments in 1,4-Benzo- and 1,4-Naphthoquinones The ¹³C-NMR spectra of a number of substituted 1,4-benzo- and 1,4-naphthoquinones have been obtained and assigned. Effects of CH₃-, O-alkyl-, Cl-, NH₂- and N₃- substituents have been deduced for the quinoid part of the molecules and used for the calculation of ¹³C-chemical shifts.     

Efficient and Convenient Synthesis of 1,4-Benzoxazines, 1,4-Benzothiazines,Spiro-1,4-benzoxazines,and Spiro-1,4-benzothiazines

An efficient, convenient synthesis of 1,4-benzoxazines, 1,4-benzothiazines, spiro-1,4-benzoxazines, and spiro-1,4-benzothiazines derivatives was accomplished in good yields via the novel intramolecular cyclization mediated by mild base K₂CO₃ in ethanol solvent. A variety of substrates can participate in the process with good yields, making this methodology have broad applicability. All the structures of synthesized compound have been confirmed by spectral analysis.

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

Reactions of 4-acetoxy-2H-1,4-benzoxazin-3-ones with some nucleophiles

O-Acetates of 4-hydroxy and 4-hydroxy-7-methoxy-2H-1,4-benzoxazin-3-ones reacted with nucleophiles such as phenols, indoles and ethanethiol. The major reaction center is the positively-charged nitrogen atom. In the reaction with 2-methylindole, 6-position of the benzoxazinone ring is another major reaction center.     

Homo-1,4-addition to cyclo-octa-1,4-diene and cyclohepta-1,4-diene

Cyclo-octa-1,4-diene and cyclohepta-1,4-diene give the bicyclic derivatives IIa–b and IVa–b on reaction with Br₂-CCl₄ or I₂-AgClO₄-MeOH respectively. Cyclo-octa-1,4-diene also undergoes homo-1,4-addition in the Prevost reaction with I₂-AgOAc or I₂-AgOCOPh in benzene.     

Ru-catalyzed double-conjugate 1,4-addition of indoles to symmetric enones

Double-conjugate 1,4-addition of indoles to dibenzylidenacetones using Ru^III as catalyst is reported. It was found that the system involving Ru^III catalyzes formation of two C–C bonds in one pot in good to high yields.     

Synthesis and characterization of polymers of 1,4-hexadienes

The homopolymerization of trans-1,4-hexadiene, cis-1,4-hexadiene, and 5-methyl-1,4-hexadiene was investigated with a variety of catalysts. During polymerization, 1,4-hexadienes undergo concurrent isomerization reactions. The nature and extent of isomerization products are influenced by the monomer structure and polymerization conditions. Nuclear magnetic resonance (NMR) and infrared (IR) data show that poly(trans-1,4-hexadiene) and poly(cis-1,4-hexadiene) prepared with a Et₃Al/α-TiCl₃/hexamethylphosphoric triamide catalyst system consist mainly of 1,2-polymerization units arranged in a regular head-to-tail sequence. A 300-MHz proton NMR spectrum shows that the trans-hexadiene polymer is isotactic; it also may be the case for the cis-hexadiene polymer. These polymers are the first examples of uncrosslinked ozone-resistant rubbers containing pendant unsaturation on alternating carbon atoms of the saturated carbon-carbon backbone. Polymerization of the 1,4-hexadienes was also studied with VOCl₃- and β-TiCl₃-based catalysts. Microstructures of the resulting polymers are quite complicated due to significant loss of unsaturation, in contrast to those obtained with the α-TiCl₃-based catalyst. In agreement with the literature, there was no discernible monomer isomerization with the VOCl₃ catalyst system.     

One step synthesis of dihydropyrrolo[3,2-e]indoles from 1,4-cyclohexanedione

Condensation of phenylhydrazones 1a-c with 1,4-cyclohexanedione in the presence of zinc dust, sodium acetate and acetic acid gave the 4,5-dihydropyrrolo[3,2-e]indoles 7a-c. Oxidation of 7a with DDQ afforded the fully aromatic pyrroloindole 16.     

Studies on the reactivity of phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone: reactions with indole derivatives and other C-nucleophiles

[reaction: see text] Thermal decomposition of phenyliodonium ylide of 2-hydroxy-1,4-naphthoquinone (lawsone) in the presence of indole derivatives affords 3-acylated indoles existing in their enol forms, through a ring contraction and alpha,alpha'-dioxoketene formation reaction. The same reactants afford 3-(3-indolyl)-2-hydroxy-1,4-naphthoquinones in a copper-catalyzed reaction. Enamines, among other C-nucleophiles tested, give analogous results.     

Water-based Synthesis and Properties of a Scandium 1,4-Naphthalenedicarboxylate

A new scandium naphthalenedicarboxylate with the framework composition [Sc₂(1,4-NDC)₃] (H₂-1,4-NDC = 1,4-naphthalenedicarboxylic acid) was obtained under hydrothermal synthesis conditions. A structure model could be developed by a combination of 3D electron diffraction measurements and computationally assisted structure determination, which was further validated by a good agreement with the experimental powder X-ray diffraction pattern. The structure consists of isolated ScO₆ octahedra interconnected by the carboxylate groups of linker molecules to form chains. These chains are connected by the naphthalene-moieties to form a three-dimensional framework with square-shaped pores and the organic group pointing into the pores. Although very similar synthesis conditions were chosen, [Sc₂(1,4-NDC)₃] is not isostructural to aluminum naphthalenedicarboxylate [Al(OH)(1,4-NDC)], which crystallizes in a MIL-53 type structure. This can be traced back to the different inorganic building units that are observed. The compound was thoroughly characterized by elemental analysis, IR spectroscopy, sorption measurements, thermogravimetric analysis and luminescence measurements. [Sc₂(1,4-NDC)₃] exhibits a high thermal stability and a ligand-based blue luminescence in the solid state at room temperature.     

Homolytic amination of benzo-1,4-dioxane

When 5,6-benzo-1,4-dioxane was reacted with N,N-dialkylchloramines in the presence of FeSO₄ at 10–20C in a solution of acetic and sulfuric acids, 6-(N,N-dialkylamino)benzo-1,4-dioxanes and 6-chloro- and 6,7-dichloro-benzo-1,4-dioxanes were obtained. Under the conditions used in the study mainly chlorination products were synthesized. Reaction of 5,6-benzo-1,4-dipxane with the system (NH₃OH)₂SO₄-TiCl₃ resulted in the formation of 6-aminobenzo-1,4-dioxane.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 316–318, March, 1989.     

The synthesis of novel heteroaryl-fused 7,8,9,10-tetrahydro-6H-azepino[1,2-a]indoles, 4-oxo-2,3-dihydro-1H-[1,4]diazepino[1,7-a]indoles and 1,2,4,5-tetrahydro-[1,4]oxazepino[4,5-a]indoles. Effective inhibitors of HCV NS5B polymerase

Three synthetic approaches have been developed that allow efficient access to novel heteroaryl fused indole ring systems, including: 7,8,9,10-tetrahydro-6H-azepino[1,2-a]indoles, 4-oxo-2,3-dihydro-1H-[1,4]diazepino[1,7-a]indoles and 1,2,4,5-tetrahydro-[1,4]oxazepino[4,5-a]indoles. Each strategy is fully exemplified and the relative merits and limitations of the approaches are discussed. The hepatitis C virus (HCV) non-structural 5B (NS5B) polymerase inhibitory activities of select examples from each molecular class are briefly presented.