2种吲哚衍生物的N-烷基化产物的制备

吲哚-3-乙醛酸甲酯和3-吲哚乙腈在碱存在下,以烷基卤或硫酸烷基酯为亲电试剂进行N-烷基化反应,合成了6种新的N-烷基化吲哚化合物。 研究了吲哚化合物及烷基化试剂的结构、溶剂和碱对N-烷基化反应的影响。 具有强吸电子取代基的吲哚-3-乙醛酸甲酯使用弱碱Cs2CO3在室温就可顺利进行烷基化反应,产率达到93%;而具有较弱吸电子取代基的3-吲哚乙腈,需要使用强碱NaH才能进行烷基化反应。     

高效液相色谱手性固定相法直接拆分4种吲哚类衍生物

将纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)涂敷于自制的球形氨丙基硅胶上,制备成了纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相(CDMPC-CSP)。利用正相高效液相色谱,在该固定相上对新合成的4种吲哚类衍生物对映体进行了手性拆分。通过选择不同结构和浓度的醇类改性剂,优化了色谱分离条件,同时探讨了醇的结构和浓度对于对映体拆分和保留的影响。结果表明,适合Ⅱ~Ⅳ号样品拆分的醇类改性剂分别为正丁醇、乙醇和乙醇,而适合Ⅰ号样品的醇类改性剂为乙醇和正丙醇组成的混合体系。在优化的各流动相体系下,4种吲哚类衍生物的对映体都得到了很好的分离。在此基础上计算了它们的对映体过量值(e.e.值)。实验结果令人满意,表明高效液相色谱手性固定相法是拆分这类化合物的一种理想方法。     

Palladium‐Catalyzed One‐Pot Three‐ or Four‐Component Coupling of Aryl Iodides,Alkynes, and Amines through CN Bond Cleavage: Efficient Synthesis of Indole Derivatives

An efficient synthesis of N‐substituted indole derivatives was realized by combining the Pd‐catalyzed one‐pot multicomponent coupling approach with cleavage of the C(sp³)?N bonds. Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene–phosphine ligand showed high efficiency. A variety of aryl iodides, including cyclic and acyclic tertiary amino aryl iodides, and substituted 1‐bromo‐2‐iodobenzene derivatives could be used. Both symmetric and unsymmetric alkynes substituted with alkyl, aryl, or trimethylsilyl groups could be applied. Cyclic secondary amines such as piperidine, morpholine, 4‐methylpiperidine, 1‐methylpiperazine, 2‐methylpiperidine, and acyclic amines including secondary and primary amines all showed good reactivity. Further application of the resulting indole derivatives was demonstrated by the synthesis of benzosilolo[2,3‐b]indole.     

The GLC Separation of Hydroxyl-Substituted Amines of Biological Importance Including the Catecholamines. Preparation of Derivatives for Electron Capture Detection

Abstract

The catecholamines and related biological amines have been converted to trimethylsilyl ether-amide derivatives through a two-step reaction sequence. All hydroxyl groups (phenolic and alcohol) were converted to TMSi ethers by reaction with TSIM. N-acylimidazole was added to the reaction mixture to effect the acylation of primary and secondary amines. TMSi-Ac (trimethylsilyl ether-acetyl) and TMSi-HFB (trimethylsilyl ether-heptafluorobutyryl) derivatives were studied. The HFB derivatives had excellent GLC properties. It is proposed to compare the sensitivity of detection of these and related compounds by flame ionization and by electron capture detection systems.     

Electronic Substitution Effect on the Ground and Excited State Properties of Indole Chromophore: A Computational Study**

Indole, being the main chromophore of amino acid tryptophan and several other biologically relevant molecules like serotonin, melatonin, has prompted considerable theoretical and experimental interest. The current work focuses on the investigation of substitution effect on the ground and excited electronic states of indole using computational quantum chemistry. Having three close-lying excited electronic states, the vibronic coupling effect becomes extremely important yet challenging for the photophysics and photochemistry of indole. Here, we have evaluated the performance of time-dependent density functional theory against available experimental and ab initio results from the literature. The electronic effects on the excited states of indole and indole derivatives e. g. tryptophan, serotonin and melatonin are reported. A bathochromic shift has been observed in the absorption spectrum for the L_a state. The absorption wavelength increases in the order of indole<tryptophan <serotonin <melatonin. While the contribution of the in-plane small adjacent groups increases the electron density of the indole ring, the out-of-plane long substituent groups have minor effect. The absorption spectra calculated including the vibronic coupling are in good agreement with experiments. These results can be used to estimate the error in photophysical observables of indole derivatives calculated considering indole as a prototypical system.     

吲哚衍生物合成与应用的研究进展

综述了以苯胺衍生物(或硝基苯衍生物)为原料合成吲哚衍生物的方法和吲哚衍生物的应用。吲哚类化合物的合成方法主要有：Fischer合成法,苯胺衍生物合成法,硝基衍生物合成法和Nenitzescu合成法等。吲哚衍生物在制药、染料和香料等领域有重要应用。参考文献105篇。     

Triflic Acid–Catalyzed Michael Reactions of Indole and Pyrrole Compounds with α,β‐Unsaturated Ketones in Water

The Michael reactions of indole and pyrrole compounds to α,β‐unsaturated ketones catalyzed by triflic acid (HOTf, 0.1–1 mol%) were performed in water to give alkylated indoles (3a–m) and dialkylsubstituted pyrroles (6a–b) in good to excellent yields.     

3-取代吲哚衍生物抗肿瘤活性研究进展

吲哚是一种自然界中广泛存在的化合物,具有抗肿瘤、抗氧化、抗菌等生物活性。在吲哚3-位引入不同的取代基,进行结构的修饰与改造一直是药物研究的热点。本文归纳总结了近年来相关的文献,对吡唑及吡唑啉类、二唑及三唑类、与2-位成环类等不同杂环取代的3-取代吲哚衍生物的抗肿瘤活性进行系统性的综述,以期为高活性抗肿瘤药物的研发提供一定的理论基础。     

Diazotised 4-Nitroaniline as a Chromogenic Reagent for the Determination of Indole Derivatives in Certain Pharmaceutical Preparations

Abstract

A sensitive colorimetric method has been devised for microdetermination of six indole derivatives; ergotamine tartrate, methylergometrine maleate, dihydroergocornine methanesulphonate, dihydroergocristine methanesulphonate, dihydroergocryptine methanesulphonate and pindolol, both in pure form and in pharmaceutical preparations. The method is based on the reaction of indole moiety with diazotised 4-nitroaniline in buffer solution of pH 6 to produce a stable yellow monoazo dye. Beer's law is obeyed over final concentration ranges 8–32 μgm1^?1 for ergotamine tartrate, 4–48 μgml^?1 for methylergometrine maleate, 8–56 μgml^?1 for dihydro-ergot alkaloids and 1–10 μgml^?1 for Pindolol with apparent molar absorptivity range (7.62 × 10³?2.61 × 10⁴) 1.mole^?1.cm^?1. A study has been made to determine the optimum conditions of the colour reaction.     

Fischer吲哚合成法的研究进展

吲哚及其衍生物具有某些生物活性, 其合成方法很多. 其中Fischer吲哚合成是最便捷和经济的合成方法, 应用最多. 对此法近十年来的合成工艺进行了综述和评价.     

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.     

Catalytic Reaction of Aryldiazoacetates with Indole and Its Derivatives:Profound Effect of N‐1 Substitutent on the Reaction Pathways

The reaction of indole and its derivatives with aryldiazoacetates has been studied in the presence of copper and rhodium catalysts. The electronic property of N-1 substitutent showed significant effect on the reaction pathways. The electron-donating group favored the formation of the β-alkylation products, while the electron-withdrawing group favored the formation of the cyclopropane products. A reaction mechanism was proposed based on the experimental data and previous research results. The structure of aryl group in diazo compounds also affected the yield of the β-alkylation products or the cyclopropane products.     

Asymmetric Dearomatization of Indole Derivatives with N‐Hydroxycarbamates Enabled by Photoredox Catalysis

Dearomatization of indoles provides efficient synthetic routes for substituted indolines. In most cases, indoles serve as nucleophiles. Reported here is an asymmetric dearomatization reaction of indole derivatives that function as electrophiles. The combination of a photocatalyst and chiral phosphoric acid open to air unlocks the umpolung reactivity of indoles, enabling their dearomatization with N‐hydroxycarbamates as nucleophiles. A variety of fused indolines bearing intriguing oxy‐amines were constructed in excellent yields with moderate to high enantioselectivities. Mechanistic studies show that the realization of two sequential single‐electron transfer oxidations of the indole derivatives is key, generating the configurationally biased carbocation species while providing the source of stereochemical induction. These results not only provide an efficient synthesis of enantioenriched indoline derivatives, but also offer a novel strategy for further designing asymmetric dearomatization reactions.     

Indole synthesis by radical cyclization of o-alkenylphenyl isocyanides and its application to the total synthesis of natural products

Development of indole synthesis by tin-mediated radical cyclization of o-alkenylphenyl isocyanide is described. Upon heating o-alkenylphenyl isocyanide in the presence of tri-n-butyltin hydride and AIBN, 2-stannyl-3-substituted indole was formed via 5-exo-trig cyclization of the imidoyl radical intermediate. After acidic workup, 3-substituted indoles were isolated. For substrates bearing simple alkyl groups, a substantial amount of tetrahydroquinoline derivatives were generated through 6-endo-trig cyclization. This undesired cyclization was suppressed by using an excess amount (five equivalents based on o-alkenylphenyl isocyanide) of ethanethiol instead of tri-n-butyltin hydride. The 2-stannylindole intermediates proved to be a suitable substrate for Stille coupling, giving 2,3-disubstituted indoles in a one-pot procedure. In addition, the 2-stannylindole intermediates could be converted to 2-iodoindoles by treatment with iodine or N-iodosuccinimide. The 2-iodoindoles thus obtained served as good substrates for Heck reactions, Stille couplings, Suzuki couplings, and palladium-mediated carbonylations, to afford a variety of 2,3-disubstituted indoles. The utility of this protocol was demonstrated by application to synthetic studies on gelsemine and discorhabdin A, and the total synthesis of an aspidosperma alkaloid, (-)-vindoline.     

酸性离子液体催化合成三吲哚甲烷化合物

在酸性离子液体催化下,通过吲哚及其衍生物和吲哚甲醛反应合成了一系列三吲哚甲烷化合物。[hmim]HSO₄/EtOH 对于该反应来说,是一个高效、绿色的催化体系。     

Catalyst free sequential one‐pot reaction for the synthesis of 3‐indole propanoates/propanoic acid/propanamides as antituberculosis agents

A highly efficient catalyst free one pot four component synthesis of highly functionalized three‐substituted indole derivatives has been reported. Thus, sequential catalyst free condensation of readily available aldehydes with Meldrum's acid followed by Michael addition of indole resulting three carbon component condensed product and concurrent decarboxylation by the nucleophilic attack of ethanol/water/amines affords three‐indole propanoates/propanoic acid/propanamides in affordable yields. Further, synthesized compounds and standard drugs were evaluated against Mycobacterium tuberculosis H37Rv strain by Alamar blue assay method. Majority of the compounds exhibited the superior activity and specifically compound 4d has MIC 1.6 μg/ml, which is better than the reference drugs used.     

Search for Non-Protein Protease Inhibitors Constituted with an Indole and Acetylene Core

A possible inhibitor of proteases, which contains an indole core and an aromatic polar acetylene, was designed and synthesized. This indole derivative has a molecular architecture kindred to biologically relevant species and was obtained through five synthetic steps with an overall yield of 37% from the 2,2′-(phenylazanediyl)di(ethan-1-ol). The indole derivative was evaluated through docking assays using the main protease (SARS-CoV-2-M^pro) as a molecular target, which plays a key role in the replication process of this virus. Additionally, the indole derivative was evaluated as an inhibitor of the enzyme kallikrein 5 (KLK5), which is a serine protease that can be considered as an anticancer drug target.     

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.     

Formation of Stable Solvent-trapped Carbonyl Oxides from the Ozonolysis of Indole Derivatives

Ozonolyses of ethyl indole-2-carboxylate (1a) and ethyl 1-methylindole-2-carboxylate (1b) in participating solvent, methanol, afforded α-methoxyhydroperoxides 7a and 7b in 90% and 89% yields, respectively, which are the first isolated solvent-trapped carbonyl oxides from ozonolysis of indole derivatives.     

A Divergent Enantioselective Total Synthesis of Post-Iboga Indole Alkaloids

Divergent enantioselective total syntheses of five naturally occurring post-iboga indole alkaloids, dippinine B and C, 10,11-demethoxychippiine, 3-O-methyl-10,11-demethoxychippiine, and 3-hydroxy-3,4-secocoronaridine, as well as the two analogues 11-demethoxydippinine A and D, are presented for the first time. The enantioenriched aza[3.3.1]-bridged cycle, a common core intermediate to the target molecules, was constructed through an asymmetric phase-transfer-catalyzed Michael/aldol cascade reaction. The challenging azepane ring fused around the indole ring and the [3.3.1]-bridged cycle were installed through an intramolecular S_N2′-type reaction. These cyclization strategies enabled rapid construction of the [6.5.6.6.7]-pentacyclic core at an early stage. Highlights of the late-stage synthetic steps include a Pd-catalyzed Stille coupling and a highly stereoselective catalyst-controlled hydrogenation to incorporate the side chain at C₂₀ with both R and S configurations in the natural products.