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.     

利用三氟甲基磺酸钪催化的吲哚去芳构化反应合成3,3'-双吲哚衍生物

报道了一类新颖的三氟甲基磺酸钪催化的吲哚-2-甲醇的去芳构化反应.该反应利用吲哚-2-甲醇衍生物在酸性催化下发生极性翻转的特性,将其吲哚环3-位的亲核中心转变为亲电位点,实现与另一分子吲哚发生偶联反应,合成了一系列具有环外双键结构的3,3'-双吲哚衍生物,产率中等到优秀.其中N-磺酰基团的强诱导作用和大位阻效应是吲哚-...     

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.     

Cu(OTf)_2和脯氨亚磺酰胺共同催化吲哚与N-磺酰醛亚胺的Friedel-Crafts反应

3-取代吲哚甲胺衍生物因其多种生物活性而备受关注.吲哚与N-磺酰醛亚胺的Friedel-Crafts反应是制备3-取代吲哚甲胺衍生物的主要方法,但反应中通常会伴随大量的双吲哚甲烷化合物的生成.应用Cu(OTf)_2和脯氨亚磺酰胺共同催化吲哚与N-磺酰醛亚胺的Friedel-Crafts反应,可以选择性地合成3-取代吲哚甲胺衍生物,产率为65%~93%.该方法具有底物适用性好、反应条件温和、操作简单等优点.     

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.     

基于吲哚-3-基甲醇不对称合成光学活性吲哚衍生物研究进展

吲哚-3-基甲醇在酸作用下原位生成亲电性的类乙烯基亚胺(离子)中间体,然后在手性催化剂催化下被亲核试剂进攻生成具有潜在生物活性的光学活性3-取代吲哚衍生物.综述了吲哚-3-基甲醇不对称烷基化反应、不对称还原反应以及不对称重排反应合成光学活性3-取代吲哚衍生物的研究进展.     

3-吲哚基-3-甲硫基丙烯酸酯和3-吲哚基-3-氧代丙酸酯的选择性合成

在10℃,3,3-二甲硫基丙烯酸酯、吲哚和三氟乙酸(TFA)的物质的量之比为1∶1∶15时,研究了3,3-二甲硫基丙烯酸酯的吲哚化反应.通过控制产物在硅胶的停留时间选择性制备了3-吲哚基-3-甲硫基丙烯酸酯(83%~85%)和3-吲哚基-3-氧代丙酸酯(83%~89%).反应条件温和、操作简单、产率高且选择性好.     

微波促进下三组分反应构建3-取代吲哚衍生物

吲哚化学的研究是杂环化学中最活跃的领域之一,特别是有关3-取代吲哚衍生物的合成.3-取代吲哚衍生物可以构建许多天然产物和相应具有生物活性化合物,其合成方法的研究格外令人关注.介绍了在微波辐射下,通过取代苯甲酰甲醛水合物、取代苯胺和4-羟基香豆素三组分,在三氟乙酸的催化下反应构建一系列官能团化的3-取代吲哚衍生物.该反应具有反应操作简单、原料廉价易得及原子经济性高等优点.     

FeCl_3催化的α-羟基二硫缩烯酮与吲哚的Friedel-Crafts烷基化反应

探讨了价廉易得、环境友好和无毒性的Fe Cl3催化的α-羟基二硫缩烯酮与吲哚的Friedel-Crafts烷基化反应.研究表明,在室温(25℃)条件下CH2Cl2中,在2.5 mol%Fe Cl3存在下,α-羟基二硫缩烯酮与吲哚及1-或2-位取代吲哚能有效进行Friedel-Crafts烷基化反应,高产率合成α-吲哚基二硫缩烯酮.该反应具有催化剂经济易得、用量少、反应条件温和、环境友好和操作简单等优点.     

环化反应合成2,3-二取代吲哚的研究进展

近年来,关于环化反应合成2,3-二取代吲哚的报道屡见不鲜.大多以苯肼类、苯胺类和硝基苯类等化合物为底物,在各种不同的金属及无金属催化作用下,与不同的底物反应,可以生成2,3-二取代吲哚及其衍生物.该类方法现已成为合成含氮五元杂环的一个重要手段,用来合成2,3-二取代吲哚及其衍生物.按反应底物类型的不同,对近年来环化反应合成2,3-二取代吲哚的研究进展进行了综述.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.