衍生于苯并-12-冠-4的双光子荧光Fe3+探针

合成了双光子荧光探针2,5-二氰基-1,4-二[2′-(4′-苯并-12-冠-4)乙烯基]苯(1),并进行了红外、质谱及元素分析。探针1在单、双光子荧光发射中对金属离子显示了相似的选择性,双光子过程中的选择性略优于单光子过程,并对Fe3+显示出高度选择性识别。探针1对Fe3+的单、双光子荧光强度随Fe3+浓度的升高而急剧降低;单、双光子荧光滴定过程中探针对Fe3+的络合常数分别是:5.70±0.03(logK11)与4.74±0.05(logK12)、5.76±0.04(logK11)与4.81±0.07(logK12)。探针1的双光子吸收截面(δTPA)随溶剂极性增加而减小,在甲苯与乙腈中的δTPA分别是2198,1125GM,探针与Fe3+络合后其双光子吸收截面显著减小。研究结果表明,化合物1可以作为Fe3+探针应用到单光子激发荧光与双光子激发荧光检测;可以用开发单光子荧光探针的策略来设计应用于生物成像的双光子荧光探针。     

双光子荧光探针

双光子吸收是指在强光激发下,介质分子同时吸收两个光子,从基态跃迁到两倍光子能量的激发态的过程。荧光显微成像是研究活体生物的重要工具,而最通常的细胞成像方法则是使用单光子激发荧光团的单光子显微成像。近红外光源激发的双光子荧光探针克服了单光子荧光探针的光漂白与光致毒而更适于生物检测与成像,为生命科学研究提供了更为锐利的工具。双光子荧光探针的作用机理包括分子内电荷迁移(ICT)、荧光共振能量迁移(FRET)、光诱导电子迁移(PET)与基团转换(GC) 4种方式。该文综述了双光子阳离子探针(Mg²⁺, Ca²⁺, Pb²⁺, Hg²⁺, Ag⁺, Fe³⁺, Zn²⁺, Na⁺, Cr³⁺)、双光子阴离子探针(F^-)、pH探针、双光子葡萄糖示踪器、双光子脂筏探针、双光子巯基探针、双光子半胱氨酸探针和双光子生物标记探针,以及双光子荧光探针在生物成像方面的应用,展望了双光子荧光探针的发展趋势与应用前景。     

双光子荧光探针

荧光探针作为研究生物系统必不可少的工具,借助双光子显微成像可以直观便捷地对生物活性化合物或生物功能客体成分进行实时动态三维观测与监控。近十年来发展的双光子激发荧光探针,较单光子荧光探针具有显著的优点,如高分辨率、高清晰度、高灵敏度、无光漂白、无光致毒、定靶激发、高横向与纵向分辨率、低的生物组织吸光系数及低的组织自发荧光干扰等。本文综述了近七年来的双光子阳离子探针、双光子阴离子探针、双光子SO_2探针、双光子pH探针、双光子核酸探针、双光子半胱氨酸探针、双光子活性氧探针、双光子磷酸探针、双光子CO探针、双光子Alph-细胞探针、双光子CYP1A酶探针、双光子极性、黏度与温度探针的结构特性及其在生物成像方面的应用。双光子荧光探针已被广泛应用于临床诊断、疾病监测和药物筛选上,这推动了生物化学、医学和生命研究的发展。     

用于细胞成像的双氰基二苯代乙烯衍生物双光子荧光银离子探针

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点,显著地优于单光子荧光显微成像,为生命科学研究提供了更为便利的工具.因此双光子荧光探针适合于生物检测与成像.制备了衍生于二苯代乙烯的双光子荧光银离子探针,此探针以拥有异常大的双光子吸收截面(6TPA)的4-甲基-2,5-二氰基-4'-氨基二苯乙烯(DCS)作为双光子荧光母体,以6-芳基-3,9-二硫-6-氮杂癸烷(TAU)为Ag+配体.探针显示了大的δTPA(在MeCN中,950 GM)、对银离子有高的灵敏性与选择性、强的双光子荧光(790 nm激光激发时).探针的络合常数为IgK=5.76±0.05.探针能选择性地检测和成像活细胞中的游离Ag+,可用于细胞中微量Ag+的分析检测与成像.此探针为开发理想的双光子荧光探针提供了可供借鉴的平台.     

有机巯基小分子生物荧光探针研究进展

生命体内许多重要的巯基小分子,如半胱氨酸(Cysteine,Cys)、同型半胱氨酸(Homocysteine,Hcy)和还原谷胱甘肽(Glutathione,GSH)等,在维持生命体系中的氧化还原平衡发挥着重要作用。因此,定量检测和专一性识别巯基生物分子在生物医学研究中具有非常重要的意义。荧光分析法具有操作简便、灵敏度高、选择性好、实时检测以及对生物体损伤小等优点而受到广泛关注。双光子荧光探针技术相对于单光子荧光技术具有长波吸收,短波发射、高度的三维空间选择性、大的穿透深度、避免荧光漂白和光致毒以及降低组织自发荧光干扰等特点,在生命科学领域具有广阔的应用前景。介绍了有机单光子和双光子巯基小分子荧光探针的研究现状,同时展望了有机巯基小分子荧光探针未来的研究方向。     

生物小分子成像用双光子荧光探针

生物体内活性小分子(生物小分子),不仅数量多,涉及到无机小分子,如SO_2,H_2S,NO与CO等,而更多的是有机小分子,如单煻、低聚糖、激素、辅酶、甘油、刺激因子、调节因子和维他命等;而且在病理、生理等方面有着至关重要的功能,发挥着举足轻重的作用,直接影响身体健康与疾病的发生.因此,对生物体内小分子的实时观测和监控是十分必要的,而双光子荧光探针正是实现这一目标的必选锐器.双光子荧光探针的定点激发、高横向与纵向分辨率、无光漂白性、无光致毒性和组织深度成像等诸多优点而彰显其无与伦比的优越性,可以很好地对细胞或组织内的生物小分子进行实时动态三维观测和监控.综述了近5年来相继开发的CO、单糖(葡萄糖、β-半乳糖苷酶)、SO_2、硫化氢、NO、过氧(硫)化物、硫醇/硫酚、~1O_2、甲醛、HNO、HClO、O_2~(·-)和ONOO~-等双光子荧光探针,系统全面地剖析了这些双光子荧光探针的传感机制,并展望了生物小分子显微用双光子荧光探针的发展与愿景.     

1,8-萘酰亚胺类荧光探针在双光子成像中应用的研究进展

荧光成像技术由于其灵敏度高、操作简单、可实时动态进行细胞、组织以及生物活体成像而受到极大关注,相对于单光子荧光成像技术,双光子成像技术具有高分辨率、强组织穿透性以及低的组织自发荧光干扰等显著的优越性.1,8-萘酰亚胺作为典型的电子供体-π-电子受体(D-π-A)双光子荧光染料,具有光稳定性、大斯托克斯/反斯托克斯位移等优点被广泛应用于酶、活性碳簇、活性氧簇、活性氮簇、生物硫醇、离子等的双光子成像中.依据1,8-萘酰亚胺类荧光探针发光机制,即分子内电荷转移、光诱导电子转移、荧光共振能量转移等发光机制,综述1,8-萘酰亚胺近些年来在双光子成像领域中的应用,并展望了其未来的发展趋势.     

双光子荧光探针研究及其应用*

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点而显著地优于单光子荧光显微成像,为生命科学研究提供了更为锐利的工具。而用于像离子的含量及其对生理的影响、离子参与的生理活动机制、离子与分子的作用、特定分子的分布及其相互作用等方面研究的双光子荧光探针,是实现成像的关键。双光子荧光探针的研究旨在促进双光子荧光显微镜应用的发展,促进生命科学、医学科学的快速发展,同时也带动双光子荧光探针所隶属的化学这一学科的发展。因此对双光子荧光探针的研究具有重要的理论和实践意义。该文综述了双光子荧光显微成像的优点、双光子荧光探针设计的原理及双光子荧光探针在离子分析方面的应用,并展望了这类荧光探针的发展趋势与应用前景。     

有机双光子线粒体内活性小分子荧光探针研究进展

线粒体在细胞的能量代谢中发挥着关键作用,其内部环境的微小变化会影响细胞的正常生命活动。同时线粒体内许多活性小分子在细胞的许多生理过程中也起着关键作用。因此,可视化监测线粒体自身及内部微环境的变化对于生命现象的研究和疾病的诊断与治疗具有非常重要的意义。荧光分析法因具有操作简便、灵敏度高、选择性好、实时检测以及损伤小等优点而得到了广泛的研究和应用。双光子荧光探针技术相对于单光子荧光技术具有长波吸收短波发射、高度的三维空间选择性、大的穿透深度、避免荧光漂白和光致毒以及降低组织自发荧光干扰等特点,在生命科学领域具有广阔的应用前景。该文介绍了有机双光子吸收基本原理以及有机双光子线粒体内活性小分子荧光探针的研究现状,同时对有机线粒体内活性小分子荧光探针今后的发展趋势进行了展望。     

选择性生物小分子硫醇荧光探针的研究进展

谷胱甘肽(GSH)、半胱氨酸(Cys)和高半胱氨酸(Hcy)作为生物体内含量较高的生物硫醇,在生物系统中起着重要作用。近年来,生物与环境样品中小分子生物硫醇的检测引起科学家们极大的兴趣,生物硫醇荧光探针和比色传感器得到快速发展。同时,作为更加精确的检测手段,选择性生物硫醇荧光探针的研究也得到了极大的关注。本文根据选择性生物硫醇荧光探针与生物硫醇的反应机理:醛基环化反应、丙烯酸酯加成环化反应、自然的化学连接反应、芳环取代重排反应和亲核加成-亲核取代反应,综述了近年来选择生物硫醇荧光探针的设计、合成与应用进展。     

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%.     

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.     

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.     

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.     

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.     

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.