对MgO重新水合及两类羟基的研究

采用IR、XRD、TG-DTA等手段对MgO重新水合及其两类羟基进行了研究。发现MgO水解后活性增大,在实验条件下水解仅发生在表面浅层;水合可得到自由、水合两类羟基,600℃灼烧使两类羟基脱除;自由羟基由水合羟基在碱[O^2-]作用下生成;添加Li⁺对表面两类羟基有影响。     

8-羟基喹啉制备实验装置的改进

针对传统8-羟基喹啉制备实验装置存在的不足,在现有大学有机化学教学实验的基础上,重新设计一种8-羟基喹啉合成的实验装置,该装置利用自制的微型小漏斗和常规磨口玻璃仪器连接组装。解决了8-羟基喹啉制备实验中,后期未反应的邻硝基苯酚处理和8-羟基喹啉分离问题。实验结果表明,改进后的实验装置操作简便,安全,节省时间,实验效率明显得到了提高。     

8-羟基喹啉及其铝配合物的合成、表征及发光性能——推荐一个综合化学实验

首先采用Skraup法制备8-羟基喹啉(HQ),涉及到有机实验中的回流加热、水蒸气蒸馏、结晶与重结晶等基本操作;然后利用合成的8-羟基喹啉来制备AlQ_3,通过返滴定法测定其中的铝含量;最后测量8-羟基喹啉与AlQ_3的红外光谱、核磁共振氢谱、紫外-可见光谱和荧光发射光谱。本实验涵盖合成、表征到性能测试,让学生认识和完成了一个基本的科研过程。     

离子热合成形貌可控的羟基磷灰石超细粉体

室温离子液体作为溶剂,以离子热合成法合成了羟基磷灰石超细粉体。当改变不同的离子液体作为溶剂时,可以相应调整羟基磷灰石的形貌。对羟基磷灰石分别采用X-射线粉末衍射（XRD）,扫描电子显微镜（SEM）,傅立叶变换红外光谱仪（FTIR）等进行表征。实验结果表明：所得到的羟基磷灰石为部分CO₃^2-取代的羟基磷灰石,在选用EmimBF₄为溶剂时所合成样品颗粒的尺寸、形貌更加规则、均一。与水作为溶剂相比,以离子液体BmimBr作为溶剂所合成的羟基磷灰石材料对有机染料碱性品红的饱和吸附量为43.78mg·g^-1,具有较好的吸附性能。     

一对手性Salen型席夫碱对映体的合成、结构与生物活性

采取分步反应法以1R, 2R-环己二胺(或1S, 2S-环己二胺)先后与2-羟基萘甲醛和水杨酸苯酯反应, 合成了一对手性Salen型席夫碱对映体:1R-(2-羟基苯甲酰亚胺)-2R-(2-羟基萘甲亚胺)环己烷(1a)和1S-(2-羟基苯甲酰亚胺)-2S-(2-羟基萘甲亚胺)环己烷(1b), 对其进行了单晶结构、圆二色光谱、元素分析、红外光谱表征及生物活性实验。单晶结构与圆二色光谱分析表明1a和1b互为对映体;生物活性实验显示1a具有一定的抑菌活性。     

羟基硅烷的偶极矩

用溶液法测定三甲基羟基硅烷、三苯基羟基硅烷、二甲基二羟基硅烷和二苯基二羟基硅烷的偶极矩,实验数据按 Guggenheim 法计算得到的结果分别是1.53,1.51,1.94,1.74 D。与 Grubb-Osthoff 所给两种羟基硅烷的偶极矩值相差甚大。而 Malatesta-Pizzotti 的结果是与本工作的结果相协调的。偶极矩数据指出:在二羟基硅烷的结构中,两个羟基的内旋转是受阻的,其择优排布使两个 RSi-OH 基团极矩矢量间约成102°的夹角。     

3,8-双乙酰基次卟啉二甲酯的合成

以氯化血红素(Ⅰ)为原料,经过溴化氢-冰醋酸加成反应、羟基亲核取代反应和无水氯化氢催化酯化反应制得3,8-双-(1-羟基乙基)次卟啉二甲酯(Ⅲ),然后通过琼斯试剂氧化反应制备了3,8-双乙酰基次卟啉二甲酯(Ⅳ)。 考察了血红素与溴化氢-冰醋酸饱和溶液反应过程中温度和时间对3,8-双-(1-羟基乙基)次卟啉二甲酯(Ⅲ)产率的影响;改进了酯化反应的实验条件;选用了廉价易得、选择性较好的羟基选择性氧化剂。 实验结果表明,当反应温度为35 ℃、反应时间为25 h时,血卟啉(Ⅱ)的产率最高,为98.5%;当催化剂为无水氯化氢时产物(Ⅲ)的产率最高,为72.1%;使用琼斯试剂做氧化剂使实验成本大大降低。 通过1H NMR、MS和IR测试技术对产物结构进行了表征。     

改性吐温-20的合成及其乳化性能

利用羟基硅油的羟基与丁二酸酐反应,合成带有羧基的改性羟基硅油,其羧基与吐温-20分子中的羟基发生酯化反应,合成了含改性羟基硅油的改性吐温-20。乳化实验结果表明,羟基硅油改性吐温-20比吐温-20具有更好的乳化效果,离心分离稳定性更好。     

对映-贝壳杉烯二萜分子内氢键对6, 7位羟基化学反应性影响研究

对映-贝壳杉烯二萜分子在激烈条件下进行乙酰化反应, 反应发生在半缩醛羟基, 而非仲羟基上; 该反常现象的生产可能是由于6位仲羟基与15位羰基之间形成了分子内氢键, 本文根据^1H NMR变温实验观察分子在不同温度时6位和7位羟基质子的化学位移变化值△δ/T(Hz.K^-^1), 证明了上述假定。     

羟基自由基引发的马来酸酐聚合反应机理AM1研究

用AM1方法计算了马来酸酐、羟基自由基及其加成产物α-羟基丁二酸酐基自由基的电子结构、电荷分布和键级.应用前线轨道理论和成键三原则研究了羟基自由基引发下马来酸酐聚合过程中α-羟基丁二酸酐基自由基活性中间体参与反应的可能性及其自由基聚合反应机理.计算结果表明:马来酸酐基态分子的HOMO和LUMO分别对应于双键CC的成键π-MO和反键π -MO;马来酸酐的羟基自由基加成反应活化能计算值为55 7kJ/mol;马来酸酐在羟基自由基引发下的自由基聚合产物是链式结构,与实验事实相符.     

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.