3-取代吲哚衍生物的合成*

目前吲哚化学的研究是杂环化学中最活跃的领域之一,特别是3-取代吲哚衍生物,已用于许多天然产物和相应具有生物活性化合物重要骨架的构筑,其合成方法的研究格外令人注目。近年来,由吲哚一步合成3-取代吲哚衍生物的报道剧增。本文按合成过程中所用催化剂的种类,综述近几年来由吲哚为原料一步合成二吲哚甲烷、β-吲哚酮、β-吲哚醇、β-吲哚硝基化合物和α-吲哚甲胺等为代表3-取代吲哚衍生物的研究进展。     

氮杂吲哚合成

氮杂吲哚是一类重要的杂环分子,在材料科学以及药物设计与合成中具有重要地位。由于氮杂吲哚在结构上区别于吲哚,所以一些经典的合成吲哚的方法并不很适用于氮杂吲哚的合成。近年来,金属有机化学的发展为氮杂吲哚的合成提供了更多的原料选择以及更有效的成环方式,从而为氮杂吲哚的合成开辟了新的方向。本文综述了氮杂吲哚有机合成方法学近年来的进展,介绍了通过Bartoli合成、Fischer吲哚合成、有机锂试剂、过渡金属促进以及其他方法来合成氮杂吲哚类化合物的研究,总结了合成各类氮杂吲哚(4-氮杂吲哚、5-氮杂吲哚、6-氮杂吲哚以及7-氮杂吲哚)的常用有机合成方法,为促进氮杂吲哚类化合物在药物合成化学以及材料科学方面的应用提供了基础。     

酸度调控的3,3-二乙硫基丙烯酸酯的吲哚化反应

探讨了酸度调控的3,3-二乙硫基丙烯酸酯的吲哚化反应,选择性地合成3,3-二吲哚基丙烯酸酯和3-吲哚基-3-氧代丙酸酯.研究表明,3,3-二乙硫基丙烯酸酯与吲哚反应时,在稀酸条件下,高产率生成3,3-二吲哚基丙烯酸酯,而在浓酸条件下,生成的3-吲哚基-3-乙硫基丙烯酸酯不稳定,在后处理和柱层析分离时易水解,高产率得到3-吲哚基-3-氧代丙酸酯.     

铜催化加成/取代串联反应构建四取代的三吲哚甲烷

在温和的条件下,利用3-乙酰基吲哚与吲哚的加成/取代串联反应,高效地合成了一系列高度拥挤的四取代三吲哚甲烷.该方法通过在3-乙酰基吲哚的氮原子上引入吸电子基团,提高了3-乙酰基吲哚的反应活性,具有原料廉价易得、底物适用性广、操作简便等优点.     

3-硫化吲哚类化合物合成方法的研究进展

硫化吲哚类化合物作为合成天然化合物的重要中间体,被广泛应用于有机合成化学.近年来,由于3-硫化吲哚类化合物有良好的药用价值而被广泛关注.目前,硫醇或硫酚、二硫醚、硫氯等硫化试剂被广泛应用于3-硫化吲哚类化合物合成中,3-硫化吲哚类化合物的合成方法随硫化试剂的不同而异,文章综述了3-硫化吲哚类化合物合成方法的研究进展.     

吲哚C—H芳基化反应的研究进展

吲哚类化合物是自然界中分布最广的杂环化合物之一,过渡金属催化吲哚C—H官能团化的方法是合成吲哚类化合物最有效的方法之一.综述了近几年来吲哚C—H芳基化反应的研究进展,根据吲哚骨架不同位置的C—H键活化,探讨了吲哚直接C—H芳香偶联反应的研究进展,对底物适应范围和反应机理等进行了详细论述,并就该领域的局限性和未来的发展前景进行总结和展望.     

吲哚氮杂环作为自由基受体在串联环化反应中的研究进展

含吲哚骨架衍生物因其具有多样的生物活性,广泛应用于生物活性分子的合成与修饰,特别是在药物化学、农药化学领域中.近年来,高效的吲哚环合成与后官能化反应己成为热门的研究主题,例如吲哚的不对称去芳构化反应构建螺环衍生物.不饱和烃的自由基串联反应一直是有机化学的一个重要研究分支,含吲哚母体的不饱和烃串联环化反应已经成为吲哚骨架...     

铜催化加成/取代串联反应构建四取代的三吲哚甲烷（英文）

在温和的条件下,利用3-乙酰基吲哚与吲哚的加成/取代串联反应,高效地合成了一系列高度拥挤的四取代三吲哚甲烷.该方法通过在3-乙酰基吲哚的氮原子上引入吸电子基团,提高了3-乙酰基吲哚的反应活性,具有原料廉价易得、底物适用性广、操作简便等优点.     

吲哚-2-甲酸和(S)-吲哚啉-2-甲酸的合成和相互转化研究进展

吲哚-2-甲酸和(S)-吲哚啉-2-甲酸均是具有生物活性的天然产物和众多降压药的特征结构片段,报道了它们的合成及其相互转化研究进展.吲哚啉-2-甲酸可由吲哚-2-甲酸还原制得,其中(S)-吲哚啉-2-甲酸可由外消旋体拆分或通过不对称合成法制备,其中"手性源法"作为一种新出现的方法具有较好的前景.吲哚-2-甲酸可由Fischer吲哚合成法制备,或通过取代苯胺或苯甲醛制备,也可通过吲哚啉衍生物氧化脱氢制备,其中Fischer合成法仍具有较强的竞争力.     

3,3-二取代3-吲哚-3'-基氧化吲哚的立体选择性合成

以10 mol%(R,R)-环己二胺衍生的手性双功能硫脲叔胺(4b)为催化剂,3'-吲哚-3-氧化吲哚与α-氨基砜为原料,经3'-吲哚-3-氧化吲哚与原位生成的N-Boc芳香醛亚胺的不对称Mannich反应,合成了20个3,3-二取代3-吲哚-3'-基氧化吲哚类化合物(3a~3t),分离收率54%~98%,dr值90∶10~99∶1,其结构经~1H NMR,~(13)C NMR和HR-MS(ESI-TOF)表征。     

Stereoselective Intramolecular Aminocarbonylation of 3-Hydroxypent-4-enylamides Catalyzed by Palladium

The urethanes and tosamides of 3-Hydroxypent-4-enylamine and its C₁  C₄ substituted derivatives undergo the palladium catalyzed intramolecular aminocarbonylation (0.1 equiv of PdCl₂, 3.0 equiv of CuCl₂, 3.0 equiv of NaOAc in acetic acid under ca. 1 atm of CO) to give selectively cis 3-hydroxypyrrolidine 2-acetic acid lactone and its C₂  C₅ substituted derivatives in good yields (66 – 90%), respectively.     

Synthesis of 2-sulfenylindenones by visible-light-mediated addition of sulfur-centered radicals to 1,3-diarylpropynones

A novel, visible-light-mediated method for the synthesis of 2-sulfenylindenones from easily available thiophenols (2.0 equiv.) and 1, 3-diarylpropynones (1.0 equiv.) in the presence of eosin Y (0.02 equiv.) under air atmosphere has been developed. The reaction proceeded smoothly, for a wide range of derivatives of thiophenols and 3-diarylpropynones, to give the expected products in moderate to good yields. Compared with traditional methods, this method is more convenient and avoids using stoichiometric amounts of I₂ and K₂S₂O₈.     

Surface-Mediated Hydrohalogenation of Isoprene: A Facile Preparation of Prenyl Halides

Abstract

The reaction of isoprene with SOCl₂ (0.5 mol equiv.) or PBr₃ (0.4 mol equiv.) or PI₃ (0.4 mol equiv.) in the presence of SiO₂ at ?10°C produced prenyl chloride (82%), or bromide (70%) or iodide (65%), respectively, in less than 30 min reaction time.     

Synthesis, Characterization and Luminescence Studies of Trinuclear Rhenium–Cobalt Mixed-Metal Alkynyl Complexes Containing a Tetrahedral Co2C2 Cluster Unit

The reaction of rhenium(I) diynyl complexes [Re(CO)₃(N–N)(CC--CCH)] [N–N = ^tBu₂bpy (1), bpy (2)] with Co₂(CO)₈ in THF yielded a new class of luminescent trinuclear rhenium–cobalt mixed-metal alkynyl complexes, [Co₂{-HC₂CC[Re(CO)₃(N–N)]}(CO)₆] [N–N = ^tBu₂bpy (3), bpy (4)]. Their luminescence and electrochemical properties have also been studied.     

Synthesis and properties of cross-conjugated ��,�ء�-bis-dimethylamino ketones and dinitriles with N-acetyl- and N-benzylpiperidine cycles

Reactions of N-acetyl- and N-benzyl-4-piperidones with aminal of ??-dimethylaminoac-rolein yielded ketocyanines bearing piperidine cycle. Reaction of 3-dimethylamino-1,1,3-trimethoxypropane with 1-acetylpiperidin-4-ylidenemalononitrile in the presence of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄), resulted in cross-conjugated ??,???-dimethylamino dinitrile. Protonation of ketocyanines bearing N-acetyl- and N-benzyl-piperidine cycles with Et₂O·HBF₄ (1 equiv.) furnished piperidinium salts, while protonation of the latter with Et₂O·HBF₄ (2 equiv.) afforded doubly charged 4-hydroxypolymethine salts. Unlike protonation, reaction of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-acetylpiperidin-4-one with Me₂SO₄ involved only the oxygen atom and led to a singly charged 4-methoxypolymethine salt. Methylation of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-benzylpiperidin-4-one with Me₂SO₄ (1 equiv.) involved cyclic nitrogen atom and resulted in piperidinium salt; heating of the latter with the excess of Me₂SO₄ afforded doubly charged bis-methoxysulfonate. Starting from 4-methoxytetrahydropyridinium salts, meso-methoxythiapentacarbocyanine dyes were synthesized.     

Synthesis and X-ray structure of a complex containing the trisimido borate trianion—the imido analogue of the orthoborate trianion

Reaction of BCl₃ with 2-methoxyaniline (1:6 equiv.) in toluene, and subsequent metallation with ⁿBuLi (3 equiv.) produces {[Li₄B(NR)₃·THF]⁺[BⁿBu₄]⁻·toluene}₂ (R=2-methoxyphenyl), which contains the first example of a trisimido borate trianion—the imido analogue of the orthoborate trianion, [BO₃]³⁻.     

A Novel Synthesis of 1-Aryl-9-alkyl-2, 3, 3a, 4, 9, 9a-hexahydro-1H-pyrrolo[2, 3-b] quinoxalines by lithium aluminium hydride reduction of N-phenyl-1-benzimidazolyl-succinimides

The N-substituted 1-benzimidazolyl-succinimides 6a – v (Scheme 1, Table 1 and 2) have been prepared by the reaction of benzimidazole and its derivatives with maleimides. Reduction of the N-cyclohexyl and N-cyclo-octyl substituted 1-benzimidazolyl-succinimides 6i – k with lithium aluminium hydride gives the normally expected substituted (N-alkyl-3-pyrrolidinyl)benzimidazoles 14i – k . However by LiAlH₄-reduction of the N-phenyl substituted 1-benzimidazolylsuccinimides 6a – h mainly the 1-aryl-9-alkyl-2, 3, 3a, 4, 9, 9a-hexahydro-1H-pyrrolo[2, 3-b]quinoxalines 7a – h are obtained. The mechanism of this unusual reduction has been elucidated.     

Reactions of Bis(phenylethynyl)ytterbium with Trimethylsilicon,Triphenylgermanium, and Triphenyltin Chlorides

The ytterbium phenylethynyl compound (PhCC)₂Yb(THF)₄ reacts with trimethylsilicon, triphenylgermanium, and triphenyltin chloride in tetrahydrofuran (THF) at room temperature to give the corresponding cross-coupling products: phenylethynylytterbium chloride PhCCYbCl(THF)₂ and ytterbium chloride YbCl₂(THF)₂.     

Highly Efficient [3 + 2] Cycloaddition: Click Synthesis of Novel 1H‐indol‐3‐yl‐benzo[d]imidazole Bis‐triazoles

A series of novel 1‐((1H‐1,2,3‐triazol‐4‐yl)methyl)‐2‐(1‐((1H‐1,2,3‐triazol‐4‐yl)methyl)‐5‐substituted‐1H‐indol‐3‐yl)‐6‐substituted‐1H‐benzo[d]imidazoles 5a – i have been prepared using click chemistry as an ideal strategy where [3 + 2] cycloaddition of azides with terminal alkynes has been developed as the target compounds. In route‐II, 5‐substituted‐1H‐indole‐3‐carbaldehydes 1a – c react with 5‐substituted orthophenylenediamine 8 to give desired products, that is, 6‐substituted‐2‐(5‐substituted‐1H‐indol‐3‐yl)‐1H‐benzo[d]imidazole 6a – i . Here, 6a – i react with 2 equiv of propargylbromide 7 to give novel 6‐substituted 2‐(5‐substituted‐1‐(prop‐2‐yn‐1‐yl)‐1H‐indol‐3‐yl)‐1‐(prop‐2‐yn‐1‐yl)‐1H‐benzo[d]imidazole 4a – i . 4a – i were reacted with 2 equiv of NaN₃ in t‐butanol/water (1:2) and add catalytic amount of CuSO₄.5H₂O. Stir the reaction mixture at room temperature to get the target products 5a – i . Here, obtained products contain four rings, that is, one indole, two triazoles, and one benzimidazole. The main advantages of this method are short reaction times, easy workup, higher yields (88–92%), and no by‐products formation.     

Interaction of Nitromethane with Modified Paramagnetic Defects on a Thermochemically Activated Silica Surface

It was found that the interaction of the modified paramagnetic defects SiO(CH₂) _n H₂ (n = 0.1) with nitromethane on a thermochemically activated silica surface at 300 K results in the formation of the following nitroxyl radicals: SiO(CH₂) _n CH₂ON( )CH₃ and SiO(CH₂) _n CH₂N( )CH₃. It was suggested that these radicals are the products of two different reactions of the modified paramagnetic defects: the first results from a reaction with free nitromethane; the second, from a reaction with nitromethane bound as complexes with diamagnetic surface defects.