Three-Component Reactions of 3-Arylidene-3H-Indolium Salts,Isocyanides and Amines

A multicomponent reaction of isocyanides with aryl(indol-3-yl)methylium salts and amines has been found. A series of aryl(indol-3-yl)acetimidamides was obtained in up to 96% yields. In the case of ethyl isocyanoacetate, the reaction is followed by cyclization to form 3,5-dihydro-4H-imidazol-4-one derivatives.     

The synthesis of a series of (α-amino)indol-3-yl ketones

A series of [(α-amino)indol-3-yl]-2-methyl-1-propanones and [(α-amino)indol-3-yl]cyclopentylmethanones has been synthesized by a variety of reductive reactions performed on the corresponding series of (α-azido)-indol-3-yl ketones. One of the more interesting reductive procedures involved the palladium-catalyzed decomposition of formic acid with the formation of hydrogen in situ. The (α-azido)ketones were prepared in excellent yield by the displacement of the tertiary bromine atom from the (α-bromo)ketones using sodium azide in N,N-dimethylformamide. Bromination was accomplished by using either cupric bromide in ethyl acetate/chloroform or phenyltrimethylammonium tribromide in tetrahydrofuran.     

Synthesis and some reactions of aryl 4,5-dichloroisothiazol-3-yl ketones

By acylation of benzene, toluene, and p-xylene with 4,5-dichloroisothiazole-3-carbonyl chloride the corresponding aryl 4,5-dichloroisothiazol-3-yl ketones were obtained. By reaction of 4,5-dichloroisothiasol-3-yl 4-methylphenyl ketone with piperidine, alkyl(aryl) thiolates, sodium alcoholates, and 2,4-dinitrophenylhydrazine were synthesized 4-methylphenyl 5-piperidyl-4-chloroisothiazol-3-yl ketone, 5-alkyl(aryl)sulfanyl-4-chloroisothiazol-3-yl 4-methylphenyl ketones, 5-alkoxy-4-chloroisothiazol-3-yl 4-methylphenyl ketones, and 2,4-dinitrophenylhydrazone of the initial ketone respectively.     

Cyclic allylamine/enamine systems-6: Some reactions of 4-(indol-2-ylcarbonyl)-, 4-(indol-3-ylcarbonyl and 4-(indol- 3-ylmethyl)-1,2,5,6-tetrahydro-1 -methylpyridines

Indol-3-yl 1-methyl-1,2,5,6-tetrahydropyridin-4-yl ketone (1d) can be isomerised to indol-3-yl l-methyl-l,2,3,4-tetrahydropyridin-4-yl- ketone but the protonated form of this enamine could not be cyclised to the indole α-position. Both indol-2-yl l-methyl-l,2,5,6-tetrahydropyridin-4-yl ketone (1c) and its isomer (1d) were cyclised to 5-membered ketones by mineral acid catalysed Michael-type addition of indole β- and α-positions respectively onto the unsaturated ketone systems. Ketone (1d)was transformed to l-acetylindol-3-yl 3-acetyl-l,4,5,6-tetrahydropyridin-4-yl ketone by hot acetic anhydride. Strong base treatment of indol-3-yl(l,2,5,6-tetrahydropyridin-4-yl) methane caused isomerisation of the double bond into conjugation with the indole rather than into the endocyclic enamine position.     

Fischer Indole Synthesis of (β-Oxo)indol-3-yl Ketones Using Protected 1,3-Dicarbonyl Compounds

The condensation products of 4-methoxyphenylhydrazine and 3,3-dimethylenedithio-5-oxyaldehydes undergo Fischer cyclization to the corresponding indoles. The carbonyl-protecting group can be removed from the latter with formation of (β-oxo)indol-3-yl ketones.     

Synthesis of 2,5-dihydroxy-3-(indol-3-yl)benzoquinones by acid-catalyzed condensation of indoles with 2,5-dichlorobenzoquinone

Three methods for the conjugate addition of indoles to 2,5-dichlorobenzoquinone have been developed. A wide variety of indoles substituted with halogen, alkyl, alkoxy, and aryl groups participate in anaerobic condensation reactions promoted by HCl, H2SO4, or CH3CO2H. The hydroquinone product is partially oxidized by excess dichlorobenzoquinone and fully converted to the 2,5-dichloro-3-(indol-3-yl)benzoquinone targets by DDQ or Ag2CO3 oxidation. 2,5-Dihydroxy-3-(indol-3-yl)benzoquinones can be obtained from the dichlorides by alkaline hydrolysis. The rotational characteristics of the biaryl bond created in these reactions have been examined by theoretical and spectroscopic methods.     

Novel synthesis of bicycles with fused pyrrole, indole, oxazole, and imidazole rings

Reactions of benzotriazol-1-yl(1H-pyrrol-2-yl)methanone 10 and benzotriazol-1-yl(1H-indol-2-yl)methanone 11 with diverse ketones, isocyanates, and isothiocyanates in the presence of base afforded pyrrolo[1,2-c]oxazol-1-ones 1, oxazolo[3,4-a]indol-1-ones 2, pyrrolo[1,2-c]imidazoles 3, and imidazo[1,5-a]indoles 4 by a simple one-step procedure.     

Zeolite-catalyzed synthesis of nicotinyl-fused indolo-pyrazoles and evaluation of their activities against Anopheles arabiensis and Lipoxygenase

A series of nicotyl-fused indolo-pyrazoles (NFIPs) were synthesized by a one-pot multicomponent reaction of aryl aldehydes, isoniazid, and indole in the presence of zeolite as a catalyst. Structures of all the synthesized compounds were established by IR, ¹H-NMR, ¹³C-NMR, 2D-NMR, TOF-MS, and elemental analysis. The products were obtained in excellent yields and high purity. All 10 compounds were screened for larvicidal and insecticidal properties against Anopheles arabiensis and tested for their lipoxygenase inhibitory activity. Compounds (3-(3-hydroxy-4-methoxyphenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4i ) and (3-(3-bromo-5-hydroxy-4-methoxyphenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4j) displayed highest larvae mortality at a 4 μg/ml dose in 24 h. Compounds (3-(4-methoxyphenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4h ) and (3-(3-hydroxy-4-methoxyphenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4i ) showed a significant knockdown activity after 24 h with 70% mortality. Furthermore, (3-(4-chlorophenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4c ) and (3-(3-bromo-5-hydroxy-4-methoxyphenyl)-2,3-dihydropyrazolo[4,3-b]indol-1(4H)-yl)(pyridin-4-yl)methanone ( 4j ) displayed promising lipoxygenase inhibitory activity with a mortality of 70% and 60%, respectively.     

Synthesis of chalcone analogs and derivatives of 2-pyrazoline from 3-formylindole

By the crotonic condensation in an alkaline medium of 3-formylindole with various aromatic and heterocyclic methyl ketones, and also with cyclopentanone, cyclohexanone, and 1,4-diacetylbenzene, we have synthesized nineteen ,-unsaturated ketones. The majority of them were characterized as the 2,4-dinitrophenylhydrazones, the absorption maxima of which in chloroform are given. Some considerations are expressed concerning the reactivity of 3-formyl- and 3-acetylindoles. Ten 3-aryl-1-phenyl-5-(indol-3-yl)-2-pyrazolines and their analogs with a 3-heterocyclic residue have been synthesized by the reaction of 3-aryl-1-(indol-3-yl)propen-3-ones and the corresponding analogs with phenylhydrazine. Some of the compounds synthesized possess a bright luminescence.     

Basicity and structure of <Emphasis Type="Italic">α</Emphasis>,<Emphasis Type="Italic">β</Emphasis>-unsaturated ketones of the heterocyclic series

The protolytic equilibrium constants of five pyrrole and three indole analogs of the chalcones in the H₂SO₄-CH₃COOH system have been determined spectrophotometrically. The electronic influences of the 2-pyrryl, N-methyl-2-pyrryl, indol-3-yl, and N-methylindol-3-yl groups have been evaluated quantitatively by means of their σ⁺ parameters which are, respectively: ?2.10, ?2.07, ?2.25, and ?2.28. It has been shown that in α, β-unsaturated ketones the nitrogen-containing heterocyclic radicals 2-pyrryl and indol-3-yl, and also their N-methyl derivatives, exhibit a positive dynamic conjugation effect considerably exceeding that for 2-furyl, 2-thienyl, and 2-selenienyl.     

Eu(NTf2)3催化吲哚与醛(酮)反应合成二吲哚基甲烷

二(三氟甲基磺酰)亚胺铕(Ⅲ)[Eu(NTf2)3,Tf=SO2CF3]作催化剂,吲哚与醛(酮)在室温下发生亲电取代反应合成了一系列二吲哚基甲烷,产率85%～98%.该法反应条件温和、时间短、催化剂用量少且可以回收重复使用.     

Chemical Transformations of Tetracyclo[3.3.1.1<Superscript>3,7</Superscript>.0<Superscript>1,3</Superscript>]decane (1,3-Dehydroadamantane): VI. Reactions of 1,3-Dehydroadamantane with Carboxylic Acid Chlorides

1,3-Dehydroadamantane reacted with saturated carboxylic acid chlorides to give the corresponding 1-acyl-3-chloroadmantanes as the major products. In some cases, minor products of insertion into the C^α–H bond of acyl chloride were formed. The reactions of 1,3-dehydroadamantane with aromatic (heteroaromatic) carboxylic acid chlorides selectively afforded aryl (hetaryl) 3-chloroadamantan-1-yl ketones. The described reactions provide a synthetic route to difficultly accessible alkyl (aryl) ketones containing a 3-chloroadamantan- 1-yl group in one step under mild conditions with high yields.     

Diastereoselective synthesis of functionalized tetrahydro-γ-carbolines via a [3 + 3] cycloaddition of 2,2′-diester aziridines with β-(indol-2-yl)-α,β-unsaturated ketones

A Sc(OTf)₃-catalyzed [3 + 3] cycloaddition of 2,2′-diester aziridines with β-(indol-2-yl)-α,β-unsaturated ketones was developed, affording polysubstituted tetrahydro-γ-carbolines in single diastereoisomers in good to excellent yields.     

Application of directed metalation in synthesis. Part 8: Interesting example of chemoselectivity in the synthesis of thioaurones and hydroxy ketones and a novel anionic ortho-Fries rearrangement used as a tool in the synthesis of thienopyranones and thiafluorenones

Chemoselective synthesis of thioaurones or 3-hydroxy benzo[b]thiophen-2-aryl ketones, 1-hydroxy naphtho[2,1-b]thiophen-2-aryl ketones and chalcones from N,N-diethyl-ortho-methyl sulfanyl aryl amides were described. (Benzo[b]thiophen-2-yl) alkylates and (naphtho[2,1-b]thiophen-2-yl) alkylates undergo a novel anionic ortho-Fries rearrangement leading to (3-hydroxy benzo[b]thiophen-2-yl) and (1-hydroxy naphtho[2,1-b]thiophen-2-yl) alkyl ketones. The hydroxy ketones were used as intermediates in the synthesis of wide range of benzothienopyranones and thiafluorenones.     

Uncatalyzed addition of indoles and N-methylpyrrole to 3-formylchromones: synthesis and some reactions of (chromon-3-yl)bis(indol-3-yl)methanes and E-2-hydroxy-3-(1-methylpyrrol-2-ylmethylene)chroman-4-ones

(Chromon-3-yl)bis(indol-3-yl)methanes and E-2-hydroxy-3-(1-methylpyrrol-2-ylmethylene)chroman-4-ones have been obtained in good yields from 3-formylchromones on reaction with indoles and N-methylpyrrole under solvent-free conditions. Reactions of (chromon-3-yl)bis(indol-3-yl)methanes with guanidine carbonate and hydrazine hydrate proceed with the participation of the chromone ring system and lead to the formation of the corresponding pyrimidines and pyrazoles bearing the bis(indol-3-yl)methyl moiety.     

Acid catalyzed rearrangements of aryl 3-(2-nitroaryl)oxiran-2-yl ketones

Russian Chemical Bulletin - Studies of chemical behavior of aryl 3-(2-nitrophenyl)oxiran-3-yl ketones in acidic medium revealed the possible occurrence of two competitive rearrangements leading to...     

1-(Phenylsulfonyl)indol-2-yl Triflate: A Versatile Reagent for the Synthesis of 2-Substituted Indoles

The palladium-catalysed reaction of 1-(phenylsulfonyl)indol-2-yl triflate 1, with a variety of aryl and heteroaryl boronic acids 2 or vinyl tributylstannane 3 provides a general and an efficient method for the synthesis of 2-substituted indoles 4.     

Selenium heterocycles. XXXIII. Synthesis of thieno[3,4-b]furan,seleno[3,4-b]furan,thieno[3,4-b]indole and seleno[3,4-b]indole. four novel heterocycles

Starting from the readily available 2-methyl-3-benzoylfuran, 1-phenylthieno[3,4-b]furan and 1-phenyl-seleno[3,4-b]furan were prepared. Also, starting from phenyl 3-methylindol-2-yl ketone and aryl 2-methyl-indole-3-yl ketones a series of substituted thieno[3,4-b]indoles and substituted seleno[3,4-b]indoles were prepared.     

Transformations of 3-formylindoles under the action of acids

Under the influence of acids 3-formylindole forms urorosein (the salt of di(indol-3-yl)methylium) which is unstable in solution and decomposes to give a series of indole derivatives, among which 6-(indol-3-yl)-5H,7H-indolo[2,3-b]carbazole and tri(indol-3-yl)methylium salt predominate. N,N′-Dimethylurorosein in solution also forms a mixture of indole derivatives, from which tri(1-methylindol-3-yl)methylium salt, 5N,11N-dimethylindolo[3,2-b]carbazole and its 6-(1-methylindol-3-yl) derivative were isolated. Research Institute of New Antibiotics, RAMN (Russian Academy of Medical Science), Moscow 119867, Russia; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 631–639, May, 1999.     

Study of the transformations of 2-C-(indol-3-yl)methyl-α-l-xylo-hex-3-ulofuranosonic acid (the open form of ascorbigen) in an acidic medium

Transformation of ascorbigen in an acidic medium, which affects the carbohydrate moiety of the molecule and results in the formation of 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)cyclopent-2-enone, 5-hydroxymethyl-2-(indol-3-yl)methylidenetetrahydrofuran-3-one, and 2-(indol-3-yl)acetylfuran, was investigated. Isolation and identification of the intermediates allowed the elucidation of the mechanism of this domino-type reaction.