α-羰基重氮化合物的卡宾聚合反应研究

α-羰基重氮化合物的卡宾聚合反应(C1聚合反应)是近年发展起来的一类合成碳链聚合物的新反应类型,为合成碳链上每一个碳原子都连接有极性取代基的高度功能化聚烯烃类似物提供了烯烃聚合(C2聚合)无法替代且更为便捷有效的新途径,在功能高分子领域有广阔应用前景。本文详细描述了重氮乙酸酯、重氮乙酰胺和α-重氮酮等化合物在铜、钯、铑等过渡金属催化下的卡宾聚合反应及其反应机理,论述了α-重氮化合物参与的共聚合反应以及双-α-羰基重氮化合物的卡宾聚合反应和共聚合反应。最后,展望了卡宾聚合反应的发展趋势。     

不对称姜黄素类似物的合成及其清除自由基的研究

姜黄素类化合物中,非对称结构的单去甲氧基姜黄素具有一些特殊的生物活性.通过碱法合成2-单取代苯亚甲基环戊酮中间体,再用酸催化合成了10不对称的单羰基姜黄素类似物,多酚羟基的类似物可以不通过羟基保护直接合成,其中,除A1外其它9个为新化合物,并测试了所合成类似物对DPPH自由基的清除能力.结果表明类似物的酚羟基对自由基清...     

手性4-取代色满骨架的立体选择性构建研究进展

手性4-取代色满骨架在很多具有生物活性的天然产物及其类似物中广泛存在,该骨架的不对称构建策略在新药开发中扮演着重要角色。本文从加成反应、氢化反应、烷基化反应、烯/炔丙基化反应、去对称化反应、羰基α位芳基化反应和重排反应七个方面综述了手性4-取代色满骨架的立体选择性构建策略,以期为含有该类骨架的活性天然产物的不对称合成提供参考。     

合成前列碳环素中间体——6β(叔丁基二甲基硅氧)甲基-7-α-[(四氢吡喃-2)氧基]-双环[3.3.0]辛-3-酮

天然前列环素1具有抑制血小板聚集和舒张血管的作用,在预防中风、血栓形成及心脏病发作方面具有重要的生理意义和实用价值.但由于它极不稳定,因此合成稳定的类似物一直成为各国学者努力的目标.其中最引人注意的稳定的类似物为前列碳环素2.     

吡咯喹啉醌模型化合物与氨亲核加成的理论探讨

为了揭示辅酶PQQ结构与反应性的关系,在B3LYP/D95(d, p)水平上对一系列PQQ模型化合物及其类似物与氨的亲核加成进行了理论计算.结果表明:对单羰基体系,羰基碳的亲电性对反应能垒有重要的影响;对双羰基体系,过渡态中邻位羰基氧与亲核试剂氨上的H形成的氢键对反应的活化能起着关键的作用;稠合芳香环本身对反应的能垒影响不大,但当稠合杂环的1-位为可提供氢键受体的N原子时,由于N1与氨上H原子间可形成氢键而进一步降低反应的活化能.发现过渡态中被进攻羰基与氨上N原子之间形成的夹角(OCN)与活化能有良好的线性关系.     

愈创木烷型倍半萜类天然产物及其类似物的全合成研究进展

综述了愈创木烷型倍半萜类天然产物及其类似物的全合成研究进展.主要包括以卡宾羰基叶立德环化串联反应、烯烃复分解环化反应、分子内羟醛缩合反应等作为关键反应的方法来构筑该类天然产物的基本骨架.     

油菜甾醇内酯及其类似物的侧链部分合成新方法

以豆甾醇为原料，合成了油菜甾醇内酯及其类似物的侧链部分；并为这一类化 合物的侧链部分的合成提供了一条简便、经济、高效的合成方法。其关键步骤为醛 5及酮6之间的不对称Aldol反应，以及羰基α位的差向异构化反应。     

二苯基甲基烯丙基型膦烷与醛的Wittig反应的立体化学研究

利用3-甲氧基羰基-2-稀丙基二苯基甲基膦叶立德与醛(脂肪醛、芳香醛、杂环醛)的Wittig反应合成了5-取代-2,4-戊二烯酸甲酯(ABA酯类似物),研究了碱对Wittig反应立体化学的影响,发现了该类型季鏻盐的Wittig反应具有很好的4E选择性,并提出了可能的反应机理.     

新型含哒嗪酮基双酰肼类化合物的3D-QSAR研究

用比较分子场分析方法对1-芳基-1，4-二氢-3-酰肼羰基-6-甲基-4-哒嗪酮类化合物进行了三维定量构效关系研究，发现影响其促进黄瓜子叶生根活性的主要为立体能.立体能与静电能之比为0.733:0.267.所得到的模型交叉验证值rCV2=0.643，相关系数r2=0.977, F=102.622, s=0.041，表明模型具有较好的预测能力.研究结果对3-酰肼羰基-4-哒嗪酮类化合物的改性或新类似物的合成具有指导意义.     

芳基氟喹诺酮抗菌剂的合成新方法

提出了一种合成芳基氟喹诺酮抗菌剂二氟沙星和替马沙星的新方法，以2，4- 二氯-5氟苯乙酮为原料，用草酸二乙酯代替文献报道的碳酸二惭酯与之反应，高收 率得到β-酮酸酯，该酮酸酯经乙氧亚甲基化、胺化、环合和水解反应制得比文献 报道的类似物多一个羰基的中间本，再经过氧化物氧化脱羰基，与哌嗪衍生物缩合 制得标题化合物，所制得的新化合物的结构由~1H NMR, IR, MS和元素分析确证。     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.     

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.     

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.