α-卤代酮的脱卤新方法

报道了一种以乙醇为溶剂,在锌粉和甲酸铵催化下的α-卤代酮的脱卤新方法。该体系也适用于α,α-二卤代酮和卤代苄的脱卤反应,产物结构结构经~1H NMR,IR和MS(ESI)确证。     

α-卤代酮和羰基化合物在碘化钾/金属盐作用下的碳-碳双键形成反应

本工作研究了α-卤代酮与羰基化合物之间在易得试剂碘化钾和某些硬路易斯酸的金属盐, 如三氯化铝, 四氯化钛等复合作用下形成碳碳双键, 生成(E)-α,β-不饱和羰基化合物的反应。     

活性钴引起α—溴代酮的反应

近年来,活性钛,活性镍等金属试剂正被用于有机合成并引起人们的关注。最近,对活性钴引起有机反应的研究也日益增多。例如在活性钴试剂作用下,卤代芳烃脱卤偶联得到联苯化合物,α,α—二氯二苯基甲烷脱卤得到四苯乙烯,富马酸与二溴甲烷可以发生不对称环丙烷化反应等。本文报道活性钴试剂引起α—溴代酮的反应。     

二碘化钐在脱氧、还原和碳-碳键形成反应中的应用

本文研究了二碘化钐对一些有机化合物的脱氧反应, 以及它在醇存在下对α-卤代酮、偶氮苯和苯醌的还原反应。首次报道了在二碘化钐作用下α-卤代酮与醛之间的碳-碳键形成瓜在, 高产率地制备了各种α,β-不饱和酮; 同时提出了涉及由α-卤代酮同时与Sm(II)和Sm(III)/I^-物种作用形成烯醇钐盐中间体的可能机理。     

α-溴代羰基化合物脱溴的一种简便方法

卤代物的脱卤反应是有机合成中重要反应之一,应用有机碲试剂使某些邻二溴代物脱溴反应及α-卤代羰基化合物的脱卤反应已有文献报道。我们在研究碲 Ylide 反应过程中发现二丁基碲能使某些单取代的α-溴代酮发生脱溴反应,这是一种未见文献报道的新的脱溴反应。为了考察二丁基碲作为一种新的脱溴试剂应用的可能性,我们对二丁基碲的脱     

TiCl~4-Ga还原体系中芳基三卤甲烷的还原偶联反应

研究了在低价钛(TiCl~4-Ga)试剂作用下,α,α,α-三卤甲基芳烃的还原偶联反应,得到了脱卤偶联产物-二卤代烯烃、炔烃。     

一种简单、高效合成α-卤代甲基酮化合物的新方法

发展了一种简单、高效、温和的卤代炔烃水合反应体系.在阳离子金催化剂的催化作用下,以二氯乙烷为溶剂,室温下卤代炔烃发生水合反应,高收率、高区域选择性地得到单一的α-卤代甲基酮化合物(收率≥91%).该方法具有底物适用范围广、反应条件温和和环境友好等优点,为含α-卤代甲基酮结构单元的天然产物及复杂药物分子的合成提供了新方法.     

α-卤代酮与芳香二胺经氧化-缩合过程一锅法合成喹喔啉衍生物

在二甲亚砜作用下, α-卤代酮与芳香1,2-二胺反应, 得到较高产率的喹喔啉衍生物. 结果表明反应经历一个串联的氧化-缩合过程. 二甲亚砜现场氧化α-卤代酮, 生成的二羰基化合物与芳香1,2-二胺缩合成喹喔啉衍生物.     

糖苷合成研究(ⅩⅩⅠ)2-N-(β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)-3-哒嗪酮的合成

在相转移催化条件下,2,3,4,6-四-O-乙酰基-1-溴-1-脱氧-α-D-吡喃葡萄糖1与6-(4-卤代苯基)-3(2H)-哒嗪酮2反应,合成了4种新的哒嗪酮葡萄糖苷3;然后用干燥的氨气在0～-5 ℃下处理,得相应的2-N-(β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)-3-哒嗪酮4. 这些化合物的结构经IR、1H NMR、13C NMR及元素分析所证实.     

2-溴代环己酮引发的苯乙烯原子转移自由基聚合

在铜体系催化的卤原子转移自由基聚合反应中 ,已有多种卤化物被作为引发剂使用 ,如α-卤代酯、α-卤代腈、多卤代烃、卤代苄基化合物及芳磺酰氯等 [1] ,最近又有报道称 N-氯代磺酰胺也可以作为引发剂使用 [2 ] .但以 α-卤代酮作引发剂只在钌系 [3～ 7]、铁系 [8]及镍系 [9]催化的原子转移自由基聚合中进行了研究 ,尤其是 Swawamoto等 [3～ 6] 对 Ru Cl2 (PPh3 ) 3 作催化剂 ,α,α-二氯苯甲酮和 1 ,1 ,1 -三氯丙酮作引发剂进行的甲基丙烯酸甲酯的原子转移自由基聚合进行了非常系统的研究 .由于羰基的吸电子能力较强 ,α-卤代酮的卤原子…     

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%.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.