铌酸液相催化酯化

首次以丙酸与乙醇的酯化反应为探针反应,探索了铌酸液相催化合成丙酸乙酯的适宜条件.在优化条件下,酯收率达91.5%.     

用环境友好催化剂俣成丙酸苄酯的研究

应用环境友好催化剂H－β沸石催化苯甲醇与丙酸的酯化反应,合成了丙酯苄酯。研究结果表明,H－β沸石 具有较高的催化活性。考察了苯甲醇／丙酸摩尔比、催化剂用量、反应温度、反应时间和带水剂环己烷用量对酯产率的影响。在典型反应条件（苯甲醇／丙酸摩尔比＝1.15:1、10.5gH－β沸石/摩尔丙酸、反应温度160℃ 、反应时间3.5h和20mL环己烷／摩尔丙酸）下,所得丙酸苄酯的产率为77％,该催化剂易于回收且可重复使用,具有良好的活性稳定性,并研究了用某些金属阳离子改性的β沸石的催化活性。     

铑催化乙酸乙酯羰基化合成丙酸的研究

以乙酸乙酯为原料,在金属铑催化下与一氧化碳进行羰基化反应,生成丙酸。研究了碘化物添加剂和反应条件对丙酸产率的影响。由于避免了乙醇在酸性条件下的酯化和分子间脱水等副反应,丙酸产率显著提高。乙酸乙酯羰基化具有与甲醇羰基化相似的动力学行为。碘化物添加剂的加入能有效提高反应速率和丙酸选择性。通过优化反应条件,丙酸产率大于95%。     

β—三氯锡基丙酸酯配合物和乙醇的酯交换反应研究

β—三氯锡基丙酸酯配合物和乙醇的酯交换反应研究田来进，田君廉，傅芳信（山东曲阜师大化学系曲阜２７３１６５）（东北师大化学系１３００２４）关键词：β－三氯锡基丙酸酯，配合物，酯交换反应β－三氯锡基丙酸酯是一类新型的聚氯乙烯热稳定剂中间体，其配合物可望具...     

聚苯乙烯二乙醇胺树脂催化合成丙酸苄酯的研究

应用聚苯乙烯二乙醇胺树脂（PSDEA）催化苄氯与丙酸的酯化反应，合成了丙 酸苄酯。研究结果表明，聚苯乙烯二乙醇胺树脂具有较高的催化活性。考察了丙酸 ／苄氯摩尔比、催化剂用量和反应时间对酯产率的影响，在典型反应条件（丙酸： 苄氯摩尔比＝1．25：1，16．7gPSDEA／摩尔苄氯，80℃浴温，反应4．0h）下，所 得丙酸苄酯的产率为95．5％，该催化剂易于回收且可重复使用、具有良好的活性 稳定性。     

硫酸高铈催化合成丙酸苄酯

以结晶硫酸高铈为催化剂对丙酸苄酯的合成进行了研究，考察了反应时间、催化剂用量、醇酸摩尔比和带水剂等因素对反应的影响，结果表明，在最佳反应条件下，酯化率在85％以上。     

Ni-Zn/C催化剂上乙醇气相羰基化

对镍催化剂上常压下乙醇气相羰基化合丙酸及丙酸乙酯进行了研究，结果发现，Ｎｉ－Ｚｎ／Ｃ催化剂比Ｎｉ／Ｃ具有更高的活性与选择性，实验对催化剂中Ｎｉ及Ｚｎ含量进行了优化，Ｎｉ含量５％，Ｚｎ含量３．５％时最佳，考察了反应温度对产物分布的影响，结果表明２５０℃为最佳反应温度，采用程序升温脱附技术（ＴＰＤ）对促进剂碘乙烷在活性炭，Ｎｉ／Ｃ，Ｚｎ／Ｃ及Ｎｉ－Ｚｎ／Ｃ上的行为进行了考察。实验结果表明，乙醇的甲烷化     

阴离子型聚氨酯水乳液的合成I.2,2-二羟甲基丙酸与2,6-甲苯二异氰酸酯反应动力学研究

采用二正丁胺法及ＦＴＩＲ法研究了合成阴离子型聚氨酯水乳液的核心反应，２，２－二羟甲基丙酸与２，６－甲苯二异氰酸酯的反应动力学，获得了相关的反应活化能工提出了反应动力学模型。     

活性炭固载磷钨酸催化合成丙酸丙酯

用活性碳固载磷钨酸催化剂合成了丙酸丙酯,考察了磷钨酸固载量、催化剂用量、醇酸摩尔比、反应温度、反应时间、带水剂用量对酯化反应的影响。在优化条件(催化固载量30．0％、催化剂用量2．5g/0．2mol丙酸、醇酸摩尔比1．2：1、反应温度110--116℃、反应时问2．51h、带水剂环己烷用量10mL下反应,丙酸丙酯收率为95．8％,催化剂可重复使用。     

十二烷基磺酸铁催化合成丙酸正丁酯

以十二烷基磺酸铁催化合成了丙酸正丁酯。实验结果表明最佳反应条件为：丙酸100mmol,n(丙酸)：n(正丁醇)=1．0：1．2,十二烷基磺酸铁0．8g(约1．0mmol),带水剂环己烷6mL,回流分水60min,酯化率94．6％。催化剂重复使用5次仍保持较高活性。     

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.