15N chemical shifts of a series of isatin oxime ethers and their corresponding nitrone isomers

In this article, we describe the characteristic ¹⁵N chemical shifts of isatin oxime ethers and their isomer nitrone. These oxime ethers and nitrones are the alkylation reaction products of isatin oximes. In our study, the ¹⁵N chemical shifts observed in these oxime ethers were in the 402–408 (or 22–28) ppm range, although those for their corresponding nitrone series were in the 280–320 (or ?100 to ?60) ppm range. This remarkable difference in ¹⁵N NMR chemical shift values could potentially be used to determine the O‐ versus N‐alkylation of oximes, even when only one isomer is available. In this paper, the differences in ¹⁵N NMR chemical shifts serve as the basis for a discussion about how to distinguish both regioisomers derived from the oximes alkylation. Copyright © 2010 John Wiley & Sons, Ltd.     

Chemiluminescence determination of indole derivatives in human body fluids and soil by flow injection analysis using potassium permanganate

A simple, sensitive and rapid flow-injection chemiluminescence (CL) method has been developed for the determination of indole derivatives including indole-2,3-dione (isatin) and indole-3-acetic acid (IAA), based on the increased CL reaction of potassium permanganate-formaldehyde system in acidic medium. Strong CL was observed when the indole derivatives were injected into the acidic potassium permanganate solution in a flow-cell. Under the optimum conditions, the linear range of the determination was 0.1–100.0 µM for isatin and 0.01–10.0 µM for IAA. The detection limit (3σ) was 10.0 nM for isatin and 1.0 nM for IAA. The method has been successfully applied to the determination of isatin in biological samples and of IAA in biological samples and soil extracts with satisfactory results.     

Visible-Light-Mediated Dearomatisation of Indoles and Pyrroles to Pharmaceuticals and Pesticides

Dearomatisation of indole derivatives to the corresponding isatin derivatives has been achieved with the aid of visible light and oxygen. It should be noted that isatin derivatives are highly important for the synthesis of pharmaceuticals and bioactive compounds. Notably, this chemistry works excellently with N-protected and protection-free indoles. Additionally, this methodology can also be applied to dearomatise pyrrole derivatives to generate cyclic imides in a single step. Later this methodology was applied for the synthesis of four pharmaceuticals and a pesticide called dianthalexin B. Detailed mechanistic studies revealed the actual role of oxygen and photocatalyst.     

Cu-catalyzed oxidation of indoles to isatins

The first example of Cu-catalyzed oxidation of indoles to isatin derivatives by the use of cheap aqueous tert-butyl peroxide as an oxidant was developed. This methodology is practically convenient and highly functional group tolerant, allowing a variety of indole derivatives to transform into the corresponding isatin derivatives in good yields.     

Mass-spectrometric behavior of isatin oximes

On the basis of an analysis of the mass spectra of a large series of benzo-substituted isatin oximes it is shown that their molecular ions undergo type II Beckmann rearrangment to the corresponding o-N-carboxyaminobenzonitriles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1052–1055, August, 1986.The authors thank N. A. Klyuev for his assistance in recording the high-resolution mass spectra.     

Reaction of acetyl- and 1,1′-diacetylferrocene with isatin (Pfitzinger reaction)

An efficient method for the synthesis of 2-ferrocenyl-substituted quinoline-4-carboxylic acids via the reaction of acetyl- and 1,1′-diacetylferrocene with isatin under the conditions of the Pfitzinger reaction was developed. Starting from the obtained acids methyl esters, amides, N-methyl-N-methoxyamides, and oximes (at one of the free acetyl groups) of some of these compounds were synthesized.     

Microwave‐Assisted Three‐Component Synthesis of Some Novel 1‐Alkyl‐1H‐indole‐2,3‐dione 3‐(O‐Alkyl­oxime) Derivatives as Potential Chemotherapeutic Agents

A convenient and efficient method for a one‐pot conversion of N‐alkylisatins to N‐alkylisatin O‐alkyloximes 7a – 7n as potential chemotherapeutic agents is described (Scheme) (isatin=1H‐indole‐2,3‐dione). In this method, the microwave‐assisted three‐component reaction of N‐alkylisatins 8 , hydroxylamine hydrochloride, and diverse alkyl halides in the presence of K₂CO₃ and Bu₄NBr furnishes the corresponding N‐alkylisatin O‐alkyloximes under solvent‐free condition in short times (2–10 min) and good to excellent yields (62–83%). The O‐alkylation of in situ generated isatin oximes with alkyl halides was achieved regioselectively, and (Z)‐O‐alkyloximes were produced dominantly. PM3 Semi‐empirical quantum‐mechanic calculations were performed to rationalize the evidences, and the calculations indicated a lower heat of formation for the (Z)‐O‐alkyloximes.     

A Synthesis of Dialkyl Phosphorylsuccinates from the Reaction of NH-Acids with Dialkyl Acetylenedicarboxylates in the Presence of Trialkyl(aryl) Phosphites

Summary. The reaction of dialkyl acetylenedicarboxylates with trialkyl(aryl) phosphites in the presence of isatin, phthalimide, indole, or pyrrole leads to stable dialkyl(aryl) phosphorylsuccinates in excellent yields.     

SYNTHESIS AND BIOLOGICAL ACTIVITIES OF NEW INDOLE DERIVATIVES CONTAINING SULFIDE AND/OR SULFONE MOIETIES. PART I

Abstract

4-Amino-halonitrodiphenyl sulfides(I) and/or 4-amino-halonitrodiphenyl sulfones have been found to react with isatin, N-acetyl isatin, isatin-N-Mannich bases, indole-3-carboxaldehyde and N-substituted indole-3-carboxaldehyde producing the corresponding indole derivatives. The biological activity of some of these products was screened against selected strains of bacteria.     

Biomimetic approach to perophoramidine and communesin via an intramolecular cyclopropanation reaction

[reaction: see text] Starting from tryptamine 4 and isatin 5, a biomimetic approach to the pentacyclic substructure 1 of perophoramidine and communesin was developed. The key steps were to create a stable three/six bicyclic system 2 on the 2,3-double bond of an indole derivative 3 by an intramolecular cyclopropanation, followed by ring opening of the resulting cyclopropane ring with the in situ generated amine group of an aniline.     

Sulfostyrils. IV. Reactions of 4-keto-3,4-dihydrosulfostyril

The ketone group in 4-keto-3,4-dihydrosulfostyril (I) displays anomalous properties. Its reactions are described; in some reactions it behaved normally, in others it proved quite inert. Attempted oximination of I led to extrusion of the sulfone group with formation of isatin derivatives. Compound I was converted to a tetracyclic indole derivative.     

Direct Synthesis of Structurally Divergent Indole Alkaloids from Simple Chemicals

A direct and structurally divergent synthesis of indole alkaloids from very simple 2‐vinylanilines, alkynes and TBN via a novel substrate fragmentation/cycloaddition strategy has been developed, which provides an efficient noble‐metal‐free approach to access a library of highly valuable indole derivatives of tryptamines and tryptamine‐related oximes, lactams, and lactones, as well as β‐carbolines, spiroindolines, and hexa‐hydropyrrolo[2,3‐b]indoles.     

Chemistry of indole

Indolyl keto acids were synthesized by the action of dinitriles on substituted indoles under the conditions of the Hoesch reaction. The reaction of these keto acids with isatin in alkali leads to quinoline derivatives, whereas pyridazinones of the indole series are obtained with hydrazine hydrate.See [1] for communication XLIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1512–1517, November, 1975.     

A new synthesis of some indolecarboxylic acids

1-Substituted isatins are transformed into indole derivatives by means of ethyl chloroacetate. In fact, under the conditions of the Darzens reaction they give two glycidic ester isomers 4 and 5 which, by hydrolysis in alkaline medium, undergo a transposition to indole-2,3-dicarboxylic acids 2 together with minor amounts of indole-3-carboxylic acids 3 . From isatin itself, 2,3-dicarboxyindole-1-acetic acid ( 6 ) was obtained.     

The Neber route to substituted indoles

Two complementary procedures have been developed for the conversion of the oximes of alpha-aryl ketones to azirines. On heating, the azirines rearrange smoothly to the corresponding indoles. The overall transformation offers a versatile route to indoles, complementary to the Fischer indole synthesis.     

Reactions of 3-carene, limonene, and α-pinene nitrosochlorides with imidazole, benzotriazole, and indole

The reactions of terpene nitrosochlorides derived from 3-carene, ??-pinene, and limonene, with simplest azaheterocycles (imidazole, benzotriazole, and indole) were studied. On the base of these transformations, preparative procedures to access chiral oximes bearing azaheterocyclic moieties in the ??-position to the oxime fragment, namely, ??-(1H-imidazol-1-yl)-, ??-(1H-benzo-[d][1,2,3]triazol-1-yl)-, and ??-(1H-indol-3-yl)-substituted terpenic oximes, were developed. Transformations of the studied monoterpene nitrosochlorides into ??-substituted oximes proceeded stereoselectively to give in the moderate yields (30?C60%) the only stereoisomer arising from the attack of the heterocyclic anion from the less hindered side of the intermediate nitroso olefin generated in situ from nitrosochloride.     

Access to Spiro and Fused Indole Derivatives from α,β‐Unsaturated Aldehydes Enabled by N‐Heterocyclic Carbene Catalysis

Spiro and fused indoles are attractive heterocyclic compounds with broad and promising activities in various therapeutic fields, and thus, have become the synthetic targets of organic chemists. In this account, we describe our recent progress in the synthesis of a series of spiro and fused indole derivatives through N‐heterocyclic carbene (NHC)‐catalyzed annulations of diverse NHC‐bound intermediates derived from α,β‐unsaturated aldehydes. Particularly, the novel synthesized isatin‐derived α‐bromoenals may be used as versatile 1,3‐biselectrophile synthons for combination with a range of bisnucleophiles for potentially divergent syntheses of skeletally diverse spirooxindoles in the future.     

Conversion of the quinoline ring to an indole ring

4-Nitro-3-hydroxyquinoline is readily converted to indole derivatives in aqueous alkaline and acetic acid media. The contraction of the quinoline ring to an indole ring under the conditions of mild methylation of 4-nitro-3-hydroxyquinoline in an aqueous alkaline medium proceeds through the formation of the N-methyl de rivative of 4-nitro-3-hydroxyquinoline and N-methyl-2-formyl-3-nitroindole. 3-Nitroindole is formed when 4-nitro-3-hydroxyquinoline is heated in aqueous alkali, whereas isatin is formed in acetic acid. The methylation of 4-nitro-3-hydroxyquinoline in refluxing acetic acid leads to N-methylisatin.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 513–516, April, 1979.     

Synthesis of 2,3,4,5-tetrahydro-1,5-benzox (and thi)azepines and their utilization for the preparation of condensed indoles

A preparative method is proposed for the synthesis of 2,3,4,5-tetrahydro-1,5-benzothiazepine by reductive ring expansion of 4-chromanone and 4-thiochromanone oximes. These compounds were converted to the corresponding N-amino derivatives, which, like arylhydrazines in the Fischer reaction, give new condensed indole systems. The reduction of the oxime (and its tosylate) of 5-oxo-2,3,4,5-tetrahydro-1-benzoxepine was investigated.     

Furan and Thiophene Oximes: Synthesis, Reactions, and Biological Activity. (Review)

Data on methods for the production of furan and thiophene aldoximes, ketoximes, and amidoximes and their reactions are reviewed. The synthesis of new heterocycles from furan and thiophene oximes and the biological activity of derivatives of the oximes are discussed individually.