杉木炭磺酸对4-甲基香豆素的催化合成研究

将杉木粉热解、再用发烟硫酸磺化为杉木炭磺酸,FT-IR、XPS等分析表明,磺化反应成功地将磺酸基团键合到杉木炭骨架上。杉木炭磺酸对乙酰乙酸乙酯和取代酚的Pechmann缩合反应表现了较好的催化活性,催化合成了取代4-甲基香豆素。考察了催化剂的用量等反应条件对Pechmann缩合反应收率的影响,并比较研究了杉木炭磺酸与其...     

香豆素并[4,3-b]吡喃-4-酮类衍生物的有效合成方法

在哌啶和聚乙二醇-400的作用下,通过3-乙酰基-4-羟基香豆素与芳香醛的缩合反应,合成了3-肉桂酰基-4-羟基香豆素,接着在I2-DMSO氧化体系下,成功制备了一系列香豆素并[4,3-b]吡喃-4-酮衍生物.该反应操作简单、条件温和、收率良好.产物结构经NMR,IR,MS及元素分析数据得以证实.     

新型含香豆素骨架水杨醛类Schiff碱衍生物的合成

在无溶剂条件下,以草酸为催化剂,间苯二酚与乙酰乙酸乙酯经Pechmann反应制得7-羟基-4-甲基香豆素(1);1经硝化、还原制得3-氨基7-羟基4-甲基香豆素(2);2与取代水杨醛经缩合反应合成了四个新的含香豆素骨架水杨醛类Schiff碱衍生物,其结构经1H NMR,IR和元素分析表征.     

香豆素类抗凝血药及其类似物的合成

香豆素类抗凝血药及其类似物的合成;羟基香豆素;取代苯丁烯酮;缩合;香豆素类似物     

4-羟基香豆素及其衍生物的简便合成及其荧光性质的研究

用米氏酸和苯酚在无溶剂条件下以90.6%的收率合成丙二酸单苯基酯, 然后用Eaton试剂(五氧化二磷＋甲基磺酸)在温和条件下闭环, 以78.8%的收率得到4-羟基香豆素, 将这种方法扩展合成了苯环上带有各种取代基的4-羟基香豆素衍生物以及4-羟基硫代香豆素衍生物. 并对部分4-羟基香豆素衍生物的荧光性质进行了研究.     

4-羟基香豆素在四氢喹啉及二香豆素内盐合成中的应用(英文)

以4-羟基香豆素和邻胺基苯甲醛为原料,高效合成了具有药物活性的3-位邻羟基苯甲酰基单取代的四氢喹啉衍生物.在乙醇溶剂中,反应经过克脑文格尔缩合/[1,5]-氢迁移/环化/水解/脱羧这五个串联过程进行.另外,还实现了底物控制的多样性合成,在无催化剂、无溶剂、室温条件下制备了一系列二香豆素内盐.     

1-(香豆素-3-酰基)愈创兰烃薁的合成及其抗菌活性

在醋酸铵作用下,通过1-氰乙酰基愈创兰烃薁与2-羟基苯甲醛类化合物的缩合反应,合成了一系列1-(香豆素-3-酰基)愈创兰烃薁衍生物.该反应操作简单、条件温和、收率良好.产物结构经NMR,IR,MS及元素分析数据得以证实.对所得化合物进行了抗菌活性测试,初步表明它们具有一定的活性.     

脂肪酶催化Michael加成反应合成苄丙酮香豆素抗凝血剂及其衍生物

以含水有机溶剂作为反应介质,以爪哇毛霉的天野脂肪酶M作为生物催化剂,利用4-羟基香豆素和α,β-不饱和酮的Michael加成反应,经一步催化合成了抗凝血剂苄丙酮香豆素及其衍生物;考察了反应条件对产物收率的影响.结果表明,该合成路线反应条件温和,产物收率高,有一定的实际应用意义.     

环上取代基对苯乙酮和苯甲醛缩合反应的影响

苯乙酮衍生物与苯甲醛衍生物缩合制备各种查尔酮，报道了４种苯乙酮衍生物与９种苯甲醛之间相互缩合的结果，讨论了环上取代基对缩合反应的影响。苯甲醛环上取代基，除羟基外无论是吸电子基还是给电子基对缩合反应收率影响都不大；羟基处于醛基邻位和对位的苯甲醛与几种苯乙酮衍生物的缩合，多数没有得到预期的产物，或收率极低；苯乙酮环上的羟基对缩合反应影响很大，羟基超多，缩合越困难。提出了一种假设，试图解释羟基对缩合反应     

微波辐射下氨磺酸催化水相合成3,3-亚芳基双(4-羟基香豆素)

在水介质中, 用氨磺酸作催化剂并经微波辐射, 使芳醛与4-羟基香豆素反应合成3,3-亚芳基双(4-羟基香豆素), 具有催化剂易得、环境友好、后处理简便、反应时间短和产率高等优点.     

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.     

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.     

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.     

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.