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。     

2-氨基-5-取代基4-噻唑基膦酸酯的质谱研究

本文对一系列2-氨基-5-取代基-4-噻唑基膦酸酯进行了质谱研究,发现2-氨基-5-取代基-4-噻唑基膦酸酯的膦酰基中的烷基在碎裂过程中产生了一种新的γ-烷基重排反应,并且讨论了这类化合物的质谱碎裂行为,用电子轰击碰撞活化质量分析离子动能谱(EI-CA-MIKES)和高分辨精确质量测量技术(AMMT)作了进一步的研究。     

卤代-2-(3-甲基-5-取代-4H-1,2,4-三唑-4-基)-苯甲酸的合成

邻氮基苯甲酸;缩合反应;卤代-2-(3-甲基-5-取代-4H-1;2;4-三唑-4-基)-苯甲酸的合成     

8-取代-N~6-甲基-4′-叠氮-阿糖腺苷类化合物的合成

以腺苷为起始原料,依次进行碘代、成双键、叠氮化、羟基和氨基的保护、脱碘、羟基和氨基的脱保护、Dimorth重排、8-位卤化和甲基化等反应制得8-取代-N~6-甲基-4′-叠氮-阿糖腺苷类化合物,并经1~HNMR、MS确证结构.     

3-(N-取代苯基-2-乙酰胺基)硫基-4-N-取代邻羟苯基亚胺基-5-甲基-1,2,4-三唑类化合物的合成及生物活性研究

以对称二氨基硫脲为原料,与冰醋酸反应生成5-甲基-4-氨基-1,2,4-三唑-3-硫酮(1);在弱酸性条件下,1与取代水杨醛反应生成席夫碱中间体5-甲基-4-(N-取代邻羟苯基)亚胺基-1,2,4-三唑-3-硫酮(2a～2c);最后在碱性条件下分别与N-取代苯基-2-氯乙酰胺发生烷基化反应生成15种未见报道的目标化合物3-(N-取代苯基-2-乙酰胺基)硫基-4-(N-取代邻羟苯基)亚胺基-5-甲基-1,2,4-三唑(3a～3o),其结构经IR,1H NMR,13C NMR确证.初步生物测试表明,质量分数为0.01%时,3a～3o对白色念珠菌的抑菌率均达90%以上,具有很强的抑菌活性;对金黄色葡萄球菌、大肠杆菌的抑菌率达80%以上,具有较强的抑菌活性.     

4-单取代-1,2,3-三氮唑的合成进展(Ⅱ)—通过去取代基反应

1,2,3-三氮唑衍生物是近些年研究热点化合物之一,随着4-单取代型衍生物在医药、农药、材料等领域的广泛应用,该类化合物的合成及应用近些年引起了广大研究者的关注并获得了可喜进展。本文阐述了4-单取代-1,2,3-三氮唑衍生物的合成发展历史,着重综述了近十年来该类唑衍生物的合成发展情况。内容主要涵盖二取代-1,2,3-三氮唑的去取代基反应,包括脱羧、脱苄基、脱羟(酰氧)基及脱取代乙基等反应。文章还包括一些合成方法及其产物的应用,并对一些重要的反应机理做了分析。文章最后对该类化合物的合成做了总结并展望了未来发展方向。     

N-(4-取代苯基-噻唑-2-基)香豆素类亚胺化合物的合成及抑菌活性研究

由含不同取代基的水杨醛与乙酰乙酸乙酯在哌啶存在下反应,得到乙酰基香豆素中间体,再与氨基硫脲缩合,得到含香豆素基的缩氨基硫脲化合物,继而与a-溴代芳基酮发生缩合反应,合成了9个未见报道的新的N-(4-取代苯基-噻唑-2-基)香豆素类亚胺化合物,其结构用IR,1HNMR和HRMS进行了确证,初步生物活性测定实验证明部分目标化合物具有良好的抑菌活性.     

4-取代的汉斯酯(Hantzsch Esters)作为烷基化试剂参与的有机反应

汉斯酯(Hantzsch Esters)在1881年被合成以来一直被用作还原剂参与加氢还原反应, 近年来科学家发现4-取代的汉斯酯可以发生碳碳键断裂而发生烷基迁移反应. 随后大量以4-取代的汉斯酯类化合物作为烷基化试剂的反应被报道出来, 科学家发现这类烷基化反应的历程主要是烷基自由基的迁移历程. 随着近年自由基化学的快速发展, 为这类新型烷基化试剂的应用发展提供了有力基础. 本文按照该烷基化试剂参与的反应类型分类, 进行简单介绍.     

1,3,4-噁二唑衍生物的EI谱及取代基效应的研究(Ⅰ)

本文研究了新近合成的十三个2-芳基-5(2-苯基-4-喹啉基)-1,3,4-噁二唑衍生物的电子轰击(EI-70eV)质谱。应用亚稳离子和质量准确测定方法研究了这些化合物在EI-70eV条件下的断裂途径。归纳出以环状结构的分解和重排为特征的几种主要断裂方式。并用Hammett常数σ拟合了取代基效应与裂解反应的关系。     

3-甲基-4-乙氧羰基-5-取代肼基-1H-吡唑的合成

3-甲基-4-乙氧羰基-5-取代肼基-1H-吡唑的合成;甲基乙氧羰基取代肼基-1H-吡唑;合成;波谱分析     

Stabilization Studies on Divalent Five‐Membered Rings C4H4C,C4H4Si,C4H4Ge,C4H4Sn,and C4H4Pb

Energy differences, ΔX_S‐t (X = E, H and G) (ΔX_S‐t = X_(singlet)‐X_(triplet)) between singlet (s) and triplet (t) states are calculated at B3LYP/6‐311++G (3df,2p). The DFT calculations show that the triplet state of C₄H₄C is a ground state with planar conformer respect to its corresponding nonplanar singlet state. Both singlet and triplet states of C₄H₄M (M = Si, Ge, Sn and Pb) have a planar conformer with the singlet ground state. Four isodesmic reactions are presented for determining the stability energies, SE. NICS calculations are carried out for C₄H₄M to determine the aromatic character.     

Effects of Base for the Efficient Synthesis of 4-Formylcoumarins and 4-Formylcarbostyrils

The first efficient transformation of 4-bromomethylcoumarins and 4-bromomethylcarbostyrils to 4-formylcoumarins and 4-formylcarbostyril under aqueous conditions has been achieved by modifying the Kornblum method, resulting in excellent yield. The experimental method is very simple and economical; no further purification is required and the experimental conditions have been optimized. All the isolated compounds were characterized by infrared, NMR, and mass spectroscopy, and some of the compounds have been analyzed by single-crystal x-ray analysis.     

Synthesis of 4-aminopolymethoxycoumarins from 4-hydroxycoumarin triflates

4-Aminocoumarins were synthesized in high yields by the reaction of 4-hydroxycoumarin trifluoromethanesulfonates with amines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1583–1588, September, 2006.     

NH4VO3在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中的溶解度

采用等温溶解法测定了偏钒酸铵(NH₄VO₃)在NH₄H₂PO₄-H₂O和(NH₄)₃PO₄-H₂O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH₄VO₃的溶解度随着(NH₄)₃PO₄或NH₄H₂PO₄溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH₄VO₃分别在NH₄H₂PO₄-H₂O、(NH₄)₂HPO₄-H₂O和(NH₄)₃PO₄-H₂O体系中溶解度,发现在相同的磷酸盐浓度下, NH₄VO₃的溶解度在NH₄H₂PO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在(NH₄)₂HPO₄-H₂O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg^-1时,结合pH值和反应溶度积常数K_SP等计算三个体系中的平均离子活度系数(γ_±),发现γ_±值在(NH₄)₂HPO₄-H₂O体系中最大,在(NH₄)₃PO₄-H₂O体系中居中,在NH₄H₂PO₄-H₂O体系中最小,与溶解度规律一致。     

Dehydration of 4-hydroxy-4-methyl-3-phenylamino-oxazolidin-2-ones

The dehydration of two 5,5-disubstituted 4-hydroxy-4-methyl-3-phenylaminooxazolidin-2-ones into the corresponding 4-methylene-3-phenylaminooxazolidin-2-ones has been carried out. The structure of the products was confirmed by X-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1512–1517, October, 2004.     

Facile Synthesis of 4-Oxo-4H-quinolizine-2-carboxamide Derivatives

A facile synthetic method for the construction of 2-substituted-4-oxo-4H-quinolizine-based core structure has been successfully developed. The synthesis made use of a one-pot Stobbe condensation followed by cyclization starting from the commercially available 2-pyridinecarbaldehyde. The structure of the formed 4-oxo-4H-quinolizine-2-carboxylate was fully confirmed by mass spectra, ¹H NMR and ¹³C NMR, correlation spectrography, heteronuclear multiple bond correlation, and heteronuclear single quantum coherence (HSQC) spectra. The ethyl carboxylate moiety was then further functionalized via direct aminolysis by a range of amines to afford the corresponding 4-oxo-4H-quinolizine-2-carboxamides 4a–i in moderate to good yields.     

A simple and efficient synthesis of optically pure 4-alkylisoxazolidin-4-ols

The reaction between N-hydroxyphthalimide and optically pure epichlorohydrin followed by addition of methanol represents a straightforward procedure for the synthesis of isoxazolidin-4-ols in high enantiomeric purity. Under the same conditions, the reaction of glycidyl arenesulfonates can lead to different products depending on the nature of the sulfonate. This property allowed the synthesis of both enantiomers of 4-methylisoxazolidin-4-ol from the same chiral epoxide starting material.     

2-烷硫基-5-苯基亚甲基-4H-咪唑啉-4-酮的合成与表征

用2-硫代-3-正丁基-5-苯基亚甲基4-咪唑啉二酮的-S-烷基化反应合成了2-烷硫基-3-正丁基-5-苯基亚甲基-4H-咪唑啉-4-酮衍生物。探讨了S-烷基化反应的反应条件和所合成化合物的波谱性质。目标产物均为新的化合物，其结构经元素分析，IR，1H NMR和MS确正。     

A new application of diphenylphosphorylazide (DPPA) reagent: convenient transformations of quinolin-4-one, pyridin-4-one and quinazolin-4-one derivatives into the 4-azido and 4-amino counterparts

Herein, we describe a transformation of the oxo-function of a series of quinolin/pyridin/quinazolin-4-ones into 4-azido and thence into 4-amino derivatives in moderate yields by a very short and convenient new procedure using DPPA (diphenylphosphoryl azide) as reagent. A mechanism for this interesting new application of DPPA is suggested based on the identification of some of the intermediates.