通过远端碳氮双键迁移实现非活化烯烃的三氟甲硫基化反应

利用自由基参与的官能团迁移策略实现了非活化烯烃的三氟甲硫基化反应.通过AgSCF₃和K₂S₂O₈相互作用产生的三氟甲硫基自由基与非活化烯烃反应,继而诱导远端含有碳氮双键官能团（杂芳基、亚胺）的分子内迁移,从而实现非活化烯烃的三氟甲硫基化反应.该转化具有反应条件温和、产物收率高、官能团兼容性广及区域选择性单一等特点,对具有不同电性和位阻的底物具有较好的适用性,高效构建了一系列含有三氟甲硫基的烷烃酮化合物.     

直接二氟甲硫基化与一氟甲硫基化反应研究进展

含有二氟甲硫基基团(SCF2H)与含有一氟甲硫基基团(SCFH2)的有机化合物具有独特的物理和化学性质,在医药及农药等领域具有潜在的应用价值.这两类化合物的传统制备方法是巯基底物的二氟甲基化与一氟甲基化,但含巯基底物本身种类有限,极大地限制了该类化合物的应用与开发,因此开发新的直接二氟/一氟甲硫基化方法和开拓新型直接二氟/一氟甲硫基化试剂具有重要的意义.综述了直接二氟甲硫基化反应和一氟甲硫基化反应的最新研究进展,并对反应的相关机理进行了论述.     

苯乙烯的氧化三氟甲硫基化反应

使用稳定易得的三氟甲硫基银作为"三氟甲硫基"源,通过苯乙烯的三氟甲硫基化/氧化反应,合成了一系列多取代α-三氟甲硫基苯乙酮.以二甲基亚砜和氯仿的为溶剂,过硫酸钾为氧化剂,通过自由基历程进行双官能化反应,在温和条件下,以中等到良好的收率实现了一系列不同取代的苯乙烯的氧化三氟甲硫基化的高效转化,为α-三氟甲硫基苯乙酮的合成提供了一种简单、步骤经济的有效合成方法.     

基于二氟卡宾转化的芳基和烯基碘化物的三氟甲硫基化

二氟卡宾在有机氟化物的合成中发挥了重要作用.之前的发现,二氟卡宾能与硫单质反应产生硫代氟光气,这对二氟卡宾化学的新发现以及硫代氟光气的应用研究都具有重要价值.利用这一路径已经实现了端基炔烃和烷基卤化物的三氟甲硫基化.在此,继续深入研究这一路径在合成上的应用,并实现了芳基和烯基碘化物的三氟甲硫基化.三氟甲硫基化是有机氟化学的一个重要研究方向,常用方法一般需要使用含CF₃S基团的昂贵试剂.在该方法中, CF₃S基团是由二氟卡宾、硫单质和氟离子现场产生的,所用试剂都廉价易得.     

三氟甲基亚磺酸钠实现的三氟甲基化反应研究进展

三氟甲基能够提高药物的化学和代谢稳定性,改善其亲脂性和生物利用度,增强药物的结合选择性,具有广泛的应用.三氟甲基亚磺酸钠(CF_3SO_2Na)稳定、低价,在有机氟化学领域应用广泛.综述了近三年来CF_3SO_2Na作为三氟甲基源在三氟甲基化反应中的最新研究进展,分别叙述了其在双官能团化、芳烃三氟甲基化、三氟甲硫基化及其他反应中的应用及部分反应机理,希望为今后三氟甲基的引入提供参考.     

无金属催化芳基亚磺酸钠的三氟甲硫基化反应

以N-三氟甲硫基苯胺为三氟甲硫基化试剂,乙腈为溶剂,在对甲基苯磺酸促进下,于室温反应6~8 h,实现了芳基亚磺酸钠的三氟甲硫基化反应,目标产物结构经~1H NMR,~(19)F NMR和HR-MS(ESI)确证。     

三氟甲基芳基硫醚的合成

三氟甲基芳基硫醚由于具有高疏水性和亲脂性,在医药、农用化学品及材料科学中有着重要的应用。合成含三氟甲硫基的芳香化合物已成为有机氟化学领域的研究热点之一。本文从间接法和直接法两方面综述了向分子中引入三氟甲硫基的相关研究,包括新的三氟甲硫基化试剂以及新的合成方法在制备三氟甲基芳基硫醚中的应用,最后讨论了这些方法存在的问题,并为探索新型的、更加经济的三氟甲硫基化反应提供参考。     

直接三氟甲硫基化反应研究进展

三氟甲硫基由于具有较强的吸电子性和极高的亲脂性,使得含三氟甲硫基的化合物在医药、农药以及材料等领域发挥着重要的作用.从有机氟化学的发展历程来看,三氟甲硫基化反应是继三氟甲基化反应后的又一重要研究课题,受到化学家的广泛关注.重点论述了近5年来国内外学者在直接三氟甲硫基化反应的研究成果,并讨论了三氟甲硫基化反应所面临的一些挑战.     

钯催化的芳基C-H键三氟甲硫基化反应

报道了二价钯催化的高选择性芳基C-H键的三氟甲硫基化反应,其中稳定的三氟甲硫基苯胺2a作为三氟甲硫基试剂,醋酸钯作为催化剂,苯甲酰氯和醋酸银作为添加剂,反应在DMF中120℃条件下实现的.各种取代的吡啶都可以作为该反应的导向基团.反应中苯甲酰氯的添加对活化三氟甲硫基苯胺2a起着关键作用.该反应为合成邻位三氟甲硫基取代苯类衍生物提供了高效方便的方法.     

新型含嘧啶环结构的1,3,4-噻二唑硫醚类化合物的合成及生物活性

为寻找新型杂环活性化合物,通过活性亚结构拼接方法,以硫脲和乙酰丙酮为起始原料合成4,6-二甲基嘧啶-2-硫醇,随后经醚化、肼化、环化和苄基化反应,采用微波促进方法合成了15个新型含嘧啶环结构的1,3,4-噻二唑硫醚类化合物.利用~1H NMR,~(13)C NMR,IR,ESI-MS及元素分析对其结构进行了表征确认.生物活性测试结果表明,在50μg/m L浓度下,部分目标化合物对尖孢炭疽菌、枸杞炭疽菌和草莓炭疽菌具有较好的杀菌活性,其中2-(3-氟苄硫基)-5-(4,6-二甲基嘧啶-2-甲硫基)-1,3,4-噻二唑(7i)对尖孢炭疽菌和草莓炭疽菌的抑制率分别为79.84%和73.46%;若干化合物还表现出良好的抗杜氏利什曼原虫活性,其中2-(2-氟苄硫基)-5-(4,6-二甲基嘧啶-2-甲硫基)-1,3,4-噻二唑(7h)和2-(4-氟苄硫基)-5-(4,6-二甲基嘧啶-2-甲硫基)-1,3,4-噻二唑(7j)的IC50分别为21.3和23.6μg/m L.     

醋酸酮催化二硫醚与四氢呋喃的氧化偶联反应

研究了醋酸酮催化二硫醚与四氢呋喃以氧化偶联反应构建C—S键。 结果表明,在醋酸酮(10%摩尔分数)、二硫醚(0.5 mmol)、四氢呋喃(2 mL)和双氧水(35%,2倍化学计量),反应温度120 ℃条件下,二硫醚与四氢呋喃能够顺利地发生氧化偶联反应,生成相应的C—S键化合物,合成硫醚类化合物产率中等到良好。 该反应以双氧水为氧化剂,具有环境友好等特性。     

Fe（NO3）3-9H2O/Fe（HSO4）3： An efficient reagent system for the oxidation of alcohols,thiols and sulfides in the absence of solvent

Fe（NO3）3-9H2O/Fe（HSO4）3 was used as an efficient reagent system for the oxidation of alcohols to their corresponding carbonyl compounds. All reactions were performed in the absence of solvent in good to high yields. Under the same reaction conditions, thiols and sulfides were also converted to their corresponding disulfides and sulfoxides, respectively. 2007 Farhad Shirini. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Ag/K2S2O8-Mediated Direct Thiolation and Selenylation of Carbazoles

The first direct and selective 3,6-di-thiolation and 3,6-di-selenylation of carbazoles using diaryl disulfides/diselenide as the sulfur/selenium source were demonstrated. This simple, general, and efficient method could deliver a wide range of 3,6-di-sulfenyl-carbazoles and 3,6-di-selenyl-carbazoles from readily available starting materials with high regioselectivity in an easily-operated one-step reaction via a Ag/K₂S₂O₈-mediated protocol.     

Visible-light-mediated facile synthesis of disulfides using reusable TiO2/MoS2 nanocomposite photocatalyst

A nontoxic and inexpensive TiO₂/MoS₂ nanocomposite was prepared and employed as an efficient photocatalyst for the synthesis of symmetrical disulfides under visible light irradiation at room temperature. Both aryl and alkyl thiols survived the reaction conditions, affording the corresponding disulfides in good to excellent yields. The photocatalyst could be easily recovered by simple centrifugation and filtration and reused several times without significant loss in its activity.     

Syntheses and some properties of N-unsubstituted sulfilimines

A variety of S-aminosulfonium mesitylenesulfonates, R¹R²S⁺NH₂·X⁻, were prepared in high yields by the reaction of sulfides with O-mesitylenesulfonylhydroxylamine (MSH). The thermal stability of the derived sulfilimines was examined. Reaction of allyl sulfides with MSH afforded directly the salts of allylamines in good yields, presumably via [2,3]-sigmatropic rearrangement of unisolable allylsulfilimines followed by S---N bond cleavage. The reactions of disulfides and thioketone with MSH are also described.     

Oxidation of thiols to disulfides using H2O2 catalyzed by recyclable chromic potassium sulphate at room temperature

Chromic potassium sulphate is found to be an efficient and recyclable catalyst for the selective oxidation of thiols to disulfides. The reaction was carried out in 60% methanol (v/v) using 30% H₂O₂ at room temperature. Cr(III) forms a complex with thiol which was then oxidized by H₂O₂ to produce disulfide in excellent yield after a simple workup procedure.     

KAl（SO4）2·12H2O catalyzed efficient synthesis of 3,4,6-trisubstituted 2-pyridone in water

An efficient green protocol for the preparation 3,4,6-trisubstituted 2-pyridone of employing a condensation reaction of cyanoacetamide and acetylacetone in the presence of KAl（SO₄）₂·12H₂O in water has been described.The present procedure offers advantage such as shorter reaction time,simple workup,and excellent yields.     

Preparation of 1-amidoalkyl-2-naphthol derivatives using barium phosphate nano-powders

Barium phosphate(Ba₃(PO₄)₂) nano-powder was successfully synthesized via a simple precipitation route without any surfactant. The prepared nano-powder was applied for the facile synthesis of 1-amidoalkyl-2-naphthol derivatives using multi-component reaction of aldehydes, 2-naphthol and an amide(or urea) in high yields.     

Perfluoroalkylation of 2-Thiopyrimidine Derivatives

The method of perfluoroalkylation of heterocyclic thiols and disulfides by thermolytic reaction with xenon(II) bisperfluoroalkylcarboxylates has been extended to sulfur-containing pyrimidines, including 2-mercaptopyrimidines, symmetrical disulfides, and S-trifluoroacetyl derivatives obtained from the corresponding thiols. The main reaction products are 2-SC_nF_2n+1 (n = 1, 2)-substituted pyrimidines. Their formation proceeds only via disulfides into which the initial thiols and S-trifluoroacetyl derivatives are converted in the reaction medium. Side reactions occurred in the case of trifluoromethylation linked with the perfluoroalkylation of the pyrimidine nucleus at the free 5 position (in the case of the 4,6-dimethyl derivative), or at position 4 or 4 and 5 (for unsubstituted pyrimidine). In addition, the introduction of the CF₃ group at one of the methyl substituents was confirmed by the formation of CH₂CF₃ fragment.