A four-component synthesis of novel spiro[pyrazoloquinoline-oxindoles] under solvent-free conditions

A domino reaction for the rapid and diverse synthesis of spiro[1H-pyrazolo[3,4-b]benzo[h]dihydroquinolin-4,3-indolin-2-ones] is reported. The synthesis represents a thermodynamically-favored four-component reaction between phenylhydrazine, isatins, naphthylamines, and 3-ketoesters giving the novel products in excellent yields under solvent-free conditions. Similar applications of anilines in place of naphthylamines have not led to formation of the expected 4-substituted pyrazolo[3,4-b]quinoline derivatives. The difference was ascribed to lower aromatic character of naphthylamines, with respect to anilines, which enables them to act easier as enamines in reaction with the postulated intermediates formed from condensation of isatins and the in situ generated pyrazolones. Surprisingly, 6-aminouracils in despite of their known enamine properties did not participate in reaction with isatins and pyrazolones, the merit of naphthylamines for this synthesis seems to be met by the favorable balance of their N- and C-nucleophilicity.     

Organocatalytic Atroposelective Arylation of 2‐Naphthylamines as a Practical Approach to Axially Chiral Biaryl Amino Alcohols

The first phosphoric acid catalyzed direct arylation of 2‐naphthylamines with iminoquinones for the atroposelective synthesis of axially chiral biaryl amino alcohols has been developed. This reaction constitutes a highly functional‐group‐tolerant route for the rapid construction of enantioenriched axially chiral biaryl amino alcohols, and is a rare example of 2‐naphthylamines acting as nucleophiles in an organocatalytic enantioselective transformation. Furthermore, the products, which feature various halogen atoms, provide access to structurally diverse axially chiral amino alcohols through further transformations.     

Electrochemical Organic Synthesis of Electron-Rich Biaryl Scaffolds: An Update

Biaryl scaffolds are widely spread in biologically important natural products, in numerous therapeutic agents, but they are also considered a privileged class of ligands and (organo)catalysts; therefore, the development of efficient alternative methodologies to prepare such compounds is always attracting much attention. The present review discusses the organic electrosynthesis of biaryls starting from phenols, anilines, naphthols, and naphthylamines. The most significant examples of the works reported in the last decade are presented and classified according to the single class of molecules: after the introduction, the first three sections relate to the reactions of phenols, naphthols, and anilines, respectively; the other two sections refer to cross-coupling and miscellaneous reactions.     

Notiz über die Kernresonanzspektren von trifluormethyl-substituierten Naphthalinderivaten

The proton and fluorine NMR. spectra of 25 trifluoromethyl substituted naphthalene derivatives have been analysed. The proton chemical shifts of the trifluoromethyl naphthylamines and naphthols have been correlated with calculated π-electron charge densities (PPP SCF).     

A Two Factor Simplex Optimization of An Ion Pair Liquid Chromatographic Separation

Abstract

A simple two factor simplex is used to optimize the separation of several ionic naphthylamines by varying the pH and percent methanol in the eluting solvent.     

Palladium-catalyzed amination of chloromethylnaphthalene and chloromethylanthracene derivatives with various amines

Palladium-catalyzed amination of chloromethylnaphthalene and chloromethylanthracene derivatives to produce naphthylamines and anthrylamines in satisfactory to good yields has been developed. The unprecedented amination reactions proceeded smoothly under mild conditions in the presence of Pd(PPh(3))(4) as a catalyst.     

2-Benzopyrylium salts. 29. A new approach to the synthesis of the natural alkaloid salsolidine using 2-benzopyrylium salts

The reaction of 6,7-dimethoxy-1-methyl-2-benzopyrylium salt with ammonia forms the corresponding isoquinoline, and its reaction with methylamine and benzylamine forms mixtures of the corresponding isoquinolinium salts and naphthylamines. The reduction of 2-benzyl-1-methyl-6,7-dimethoxyisoquinolinium perchlorate with sodium tetrahydroborate has given the corresponding tetrahydroisoquinoline, the hydrogenolysis of which has led to salsolidine. The products have been characterized by elementary analyses and IR and PMR spectroscopy.     

Highly diastereoselective synthesis of new indolopyrroloquinolines through intramolecular imino Diels-Alder reactions

A new, efficient and highly diastereoselective one-pot synthesis of cis-fused indolopyrroloquinoline derivatives is described through imino Diels-Alder reaction of substituted anilines or naphthylamines with N-prenylated-2-formyl-3-chloroindoles catalyzed by La(OTf)₃.     

Two-step route to indoles and analogues from haloarenes: a variation on the Fischer indole synthesis

In a new variation on the Fischer indole synthesis, readily available haloarenes are converted into a wide range of indoles in just two steps by halogen-magnesium exchange and quenching with di-tert-butyl azodicarboxylate, followed by reaction with aldehydes or ketones under acidic conditions. The protocol, which is readily extended to the preparation of indole isosteres, 4- and 6-azaindoles and thienopyrroles, obviates the need to prepare potentially toxic aryl hydrazines, simultaneously avoiding undesirable anilines such as naphthylamines.     

The Bucherer Reaction and the Preparative Use of its Intermediate Products

The study of purified intermediate products of the Bucherer reaction has shown that this reaction proceeds, not via bisulfite addition compounds of the keto form of the naphthols and the ketimine form of the naphthylamines, but via tetralonesulfonic acids and tetraloniminesulfonic acids. The intermediates lead to compounds that are otherwise difficult or impossible to obtain, and some of which are new. The mechanism of the Bucherer reaction is discussed in detail.     

6π/10π-Electrocyclization of ketene-iminium salts for the synthesis of substituted naphthylamines

An intramolecular 6π/10π-electrocyclization from ketene-iminium salts was developed for the preparation of naphthylamines. Various substituents on the nitrogen, on the aromatic ring, and on the olefin were studied. Tricyclic skeletons were obtained in few steps and good overall yields. The electrocyclization of ketene-iminium salts has been computationally explored by means of DFT calculations and their activation barriers were compared to the parent triene as well as the corresponding dienyl allenes and dienyl ketenes. Electrocyclizations for ketene-iminium salts were shown to be highly exergonic and have much smaller barriers to activation.     

Direct palladium(0)-catalyzed amination of allylic alcohols with aminonaphthalenes

The direct activation of CO bonds in allylic alcohols by palladium complexes has been accelerated by carrying out the reactions in the presence of titanium reagents. The palladium-catalyzed amination of allylic alcohols using aminonaphthalenes gave N-allylic naphthylamines in good yields. The monoallylation products are formed in the main.     

Synthesis of some new 5-substituted 1H-tetrazoles

4-Substituted 1-naphthyl selenocyanates and thiocyanates, as well as 2-naphthyl selenocyanate, were synthesized from the corresponding naphthylamines and were converted into 5-naphthyl-1H-tetrazoles by treatment with sodium azide in the presence of triethylamine hydrochloride in toluene. The structure of the newly synthesized compounds was confirmed by IR, ¹H NMR, and mass spectra. Published in Russian in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 1, pp. 153–155. The text was submitted by the authors in English.     

Coated-wire organic ion-selective electrodes in titrations based on ion-pair formation : Determination of arenediazonium salts with sodium tetraphenylborate

Titrimetric determinations of arenediazonium salts can be based on ion-pair formation between the diazonium cation and tetraphenylborate. Titrations are done under cooling with ice and are followed potentiometrically with organic ion-selective electrodes comprising PVC membranes plasticized with polar solvents and coated on aluminium wires. The method was tested in determinations of arenediazonium salts derived from 20 aromatic amines, including aniline, toluidines, naphthylamines and their derivatives. Except for compounds containing hydrophylic groups such as —COOH and —OH, the potentiometric titration curves have well defined end-points. The results are reproducible, with relative standard deviations in the range 0.4–1.4% at the millimolar level. The method can be used for reliable determinations of arenediazonium salts in analytical control of azo dyestuff production.     

Thermal Crosslinking Procedure for Preparing Solvent-Stable Polymer-Film Electrodes

Abstract

Published procedures for polymer-film electrodes often give unsatisfactory results because of instability of the film electrode interface or film dissolution. We report a procedure which involves the thermal crosslinking of polymer-film electrodes. These polymer films, prepared from a poly(vinylpyridine/styrene) copolymer, are stable toward a variety of solvents both polar and nonpolar.

Electrochemical evaluation of these crosslinked polymer films after chemical derivatization with transition metal-porphyrin.

A simple two factor simplex is used to optimize the separation of several ionic naphthylamines by varying the pH and percent methanol in the eluting solvent.     

Metabolic activation of chemical carcinogens and binding of metabolites with nucleic acid bases

A free radical was produced enzymatically by incubating benzo(a)pyrene with liver microsomes. This radical, identified as the 6-oxybenzo(a) pyrene radical, was sufficiently reactive to bind covalently with nucleic acid bases. Similar reactive free radicals were produced enzymatically from anthanthrene and 10-aza-benzo(a)pyrene, which are carcinogenic in spite of lacking so-called “bay regions.” Hepatocarcinogens such as 3′-methyl-4-dimethylaminoazobenzene and related compounds, naphthylamines, and 2-acetylaminofluorene yield free radicals after being incubated with liver microsomes. Thus, various kinds of chemical carcinogens are found to be converted to free radicals, suggesting causal significance for the formation of free radicals in chemical carcinogenesis.     

A Facile Synthesis of Benzo[h]quinolines via Silica‐TsOH‐P2O5 Promoted Condensation of 1‐Naphthylamines with 1,3‐Diketones under Solvent Free Conditions

A facile synthesis of benzo[h ]quinolines has been developed via improved Combes reaction. A combination of silica gel, p ‐toluenesulfonic acid and phosphorus pentoxide was utilized to promote the condensation of 1‐naphthylamines with 1,3‐diketones under solvent free conditions. In this case, silica gel was used as reaction media, p ‐toluenesulfonic acid and phosphorus pentoxide were acted as catalyst and dehydrating agent, respectively.     

2-Benzopyrylium salts. 29. A new approach to the synthesis of the natural alkaloid salsolidine using 2-benzopyrylium salts

The reaction of 6,7-dimethoxy-1-methyl-2-benzopyrylium salt with ammonia forms the corresponding isoquinoline, and its reaction with methylamine and benzylamine forms mixtures of the corresponding isoquinolinium salts and naphthylamines. The reduction of 2-benzyl-1-methyl-6,7-dimethoxyisoquinolinium perchlorate with sodium tetrahydroborate has given the corresponding tetrahydroisoquinoline, the hydrogenolysis of which has led to salsolidine. The products have been characterized by elementary analyses and IR and PMR spectroscopy.For communication 28 see [1].Scientific-Research Institute of Physical and Organic Chemistry, M. A. Suslov Rostov State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 815–818, November–December, 1985.     

合成龙脑与合成樟脑制备新工艺初探

报道了一种制备合成龙脑与合成樟脑的新工艺。常压下异龙脑在一种含锌催化剂作用下 ,可部分脱氢生成樟脑 ,部分异构化生成龙脑。将此产物分离提纯后可同时得到合成樟脑与合成龙脑     

Synthesis and chemiluminescent activity of 8,9‐dihydrobenzo[g] pyridazino[4,5‐b]indole‐7,10(11H)‐diones

Substituted and unsubstituted naphthylamines were transformed into the corresponding triazole derivatives, which were converted to dimethyl 1H‐benz[g]indole‐2,3‐dicarboxylates by photocyclization. The reaction of the diesters with hydrazine hydrate gave the corresponding 8,9‐dihydrobenzo[g]‐pyridazino[4,5‐b]indole‐7,10(11H)‐diones (5) . One of compounds 5 was found to have chemiluminescent activity similar to luminol.