发射长波长荧光的荧光素衍生物的设计与合成

荧光团的光谱性能决定了荧光探针的性能,发射长波长的荧光团在生物化学、分子生物学领域具有特殊应用优势,文章以间苯二酚、邻苯二甲酸酐和环己酮为原料,通过傅克酰基化反应、浓硫酸催化下的缩合反应,制备类荧光素母体,以DMF与三氯氧磷制备Vilsmeier试剂。通过Vilsmeier试剂的甲酰化反应在类荧光素母体双键上引入一个醛基,邻氨基苯硫酚再与之发生亲核反应得到荧光素衍生物(化合物4),对该化合物做了结构鉴定,测定了其紫外可见吸收与荧光光谱,与荧光素相比,其荧光激发与发射波长均红移,是个性能优良的荧光团。     

近年来ɑ-羰基二硫缩烯酮类化合物的Vilsmeier反应

在有机合成中,Vilsmeier反应一直是广泛应用的一类有机反应,其中Vilsmeier试剂是取代酰胺和卤化物形成的混合物。在Vilsmeier试剂的作用下,反应物发生甲酰化、氯化甲酰化、芳香化、重排、脱水、环化等反应,制备了大量在农药、染料和医药方面具有重要应用价值的化合物。本文主要介绍了ɑ-羰基二硫缩烯酮的Vilsmeier反应。     

荧光素水溶液的吸收光谱和荧光光谱研究及可能的应用

荧光素(Fluorescein)是重要的荧光试剂,在荧光分析中有广泛的应用。近来发现荧光素水溶液还可用于光分解水制氢,在光化学研究中也有重要意义。本文对荧光素水溶液的吸收光谱和荧光光谱进行了研究。荧光素水溶液在pH>8时其荧光发射在阳离子型表面活性剂溴代十六烷基三甲胺(CTAB)的临界胶团浓度(CMC)处有一个突变,而当溶液的pH<1时其荧光发射则在阴离子型表面活性剂十二烷基磺酸钠(SDS)的CMC处有很大的变化。而在相应的条件下荧光素水溶液的吸收光谱的变     

1,3,5-三芳基取代吡唑啉衍生物的合成及其荧光性质

通过取代苯甲醛和苯乙酮的羟醛缩合反应合成出了中间体查尔酮,然后,在微波辅助下,使查尔酮与苯肼反应合成了标题化合物,通过元素分析、红外光谱和1HNMR,对合成的化合物进行了表征,并测试了其荧光光谱,表明这类化合物具有良好的荧光性能,最大发射波长在430～450 nm范围,其荧光强度与衍生物中取代基团密切相关。     

一步法制备羧基聚苯乙烯共聚荧光微球及其表征

以苯乙烯和丙烯酸/甲基丙烯酸为单体、烯丙基荧光素为荧光染料,采用一步法制备了两种粒径均一、表面羧基化的聚苯乙烯共聚荧光微球。用环境扫描电子显微镜、荧光显微镜、红外光谱仪、荧光分光光度计等对其形貌、结构和性能进行表征。结果表明:所制备的两种羧基化共聚荧光微球单分散性好、荧光性能好且稳定;表面成功引入羧基;聚合在共聚荧光微球中的荧光素具有和烯丙基荧光素一致的性质,并证实了共聚荧光微球和烯丙基荧光素在乙醇和甲苯中具有不同荧光光谱的理论。     

1,4-二[2-(吡啶基)-1,3,4-(噁)二唑基]苯的合成及其光谱性质

利用双二酰肼的脱水化反应制备了两种新颖对称双二噁唑。通过IR、1HNMR、MS及元素分析等对化合物的结构进行表征。研究了此双噁二唑化合物在溶剂DMF中浓度为1×10-7mol/L时的紫外光谱和荧光光谱性质。结果表明:目标化合物在DMF溶液的最大紫外吸收波长在310 nm,最大荧光发射波长在364和383 nm。     

腙类荧光新试剂的合成及其分析性能的研究

合成了８种腙类试剂，对其分别进行了元素，紫外，红外和荧光光谱分析，研究了其中３种试剂和水杨醛苯并噻唑腙与金属离子的荧光反应，考察了反应酸度，介质，络合物组成比及其荧光激发与发射峰的位置，确定了测定方法的线性范围与灵敏度。     

基于BODIPY的荧光肼试剂设计、合成及其荧光性质研究

设计、合成了以丙酰肼为反应基团,以二氟化硼-二吡咯甲烷(BODIPY)为荧光团的新型标记羰基的荧光试剂4,4-二氟-l,3,5,7-四甲基-二吡咯甲川-8-丙酰肼,并对其结构进行了表征.目标产物及其与甲醛衍生产物的荧光光谱表明其荧光激发波长都为495 nm,荧光发射波长为505 nm.试剂及其衍生产物的荧光量子(乙腈)...     

3-吡啶香豆素类化合物的合成及荧光性质研究

标题化合物具有抑制单胺氧化酶活性,也具有优良的荧光性能。以4-卤代间苯二酚为原料,经甲酰化得到2,4-二羟基-5-卤代苯甲醛,再和吡啶乙酸乙酯经Knovengel反应合成了6种未见文献报道的吡啶香豆素类荧光化合物,通过红外光谱、核磁共振、质谱和元素分析对产物的结构进行了表征。同时研究了这些化合物的荧光性质,结果表明这些吡啶香豆素类荧光化合物荧光量子产率高、Stokes位移大,是优良的候选荧光团。     

Vilsmeier反应在有机合成中的应用

Vilsmeier反应在有机合成中应用极其广泛,在染料、农药、医药等合成中占有非常重要的地位。Vilsmeier试剂是取代酰胺和卤化物形成的复合物,在其作用下,反应物发生甲酰化、氯甲酰化、芳构化、重排、脱水、环化等反应。本文综述了Vilsmeier试剂、Vilsmeier反应机理以及在染料方面的应用,展望了该反应在未来工业生产的前景。     

三氯蔗糖-6-乙酯的合成工艺改进

以蔗糖为起始原料,经6位乙酰化先合成蔗糖-6-乙酯,再用双（三氯甲基）碳酸酯与二甲基甲酰胺构成的Vilsmeier试剂氯化制备了三氯蔗糖-6-乙酯,并通过。^1H NMR,^13C NMR,MS,IR确定;探讨了Vilsmeier试剂参与反应的机理及可能的副反应。实验表明最佳条件为：氯代反应中,加料顺序以BTC与DMF先生成Vilsmeier试剂、再滴加蔗糖-6-乙酯溶液为好,V（DMF）／m（蔗糖-6-乙酯）=8mL／1g;酰化反应中,n（原乙酸三甲酯）：n（蔗糖1=1．25：1;升温、保温方法及时间的控制是关键因素。该方法具有操作简单、环境友好、生产成本低等优点,有利于工业化生产。     

3,3-双(氯甲基)氧杂环丁烷的制备

以季戊四醇为原料,氯化亚砜为氯化剂,通过Ｖｉｌｓｍｅｉｅｒ试剂及控制它们的摩尔投料比和加料顺序,采用碱性氧化铝柱分离,一步制备出了可直接用于阳离子开环聚合的３,３-双（氯甲基）氧杂环丁烷（ＢＣＭＯ）,收率为７８.９％。     

2-苯基喹唑啉-4-酮的Vilsmeier反应研究

以邻氨基苯甲酸、苯甲酸酐和乙酸为原料,经过绿色合成方法合成了2-苯基喹唑啉-4-酮,然后对2-苯基喹唑啉-4-酮进行了Vilsmeier反应研究。用IR对其结构进行了表征。考察了反应时间、反应温度和投料配比对Vilsmeier反应的影响。结果表明,反应时间为4 h,反应温度为80~90℃,原料POCl3与2-苯基喹唑啉-4-酮的摩尔比为1.5：1为最佳的反应条件,收率可达67.8%。     

三氯蔗糖-6-乙酯的制备及结构表征

以蔗糖为原料,原乙酸三乙酯为酯化剂,经C-6乙酰化,生成蔗糖-6-乙酯,再用氯化亚砜和DMF制备的Vilsmeier试剂与蔗糖-6-乙酯进行氯化反应,得到三氯蔗糖-6-乙酯.考察了反应物的投料比对酯化反应的影响;反应温度、反应物的投料比和反应时间等因素对氯化反应的影响.结果表明:最佳反应条件为酯化反应温度为0℃,反应时...     

氨来咕诺的合成

以对异丙基苯酚为原料,经酯化、Fries重排、Vilsmeier反应、缩合、Micheal加成环合、水解反应合成了抗变态反应药氨来咕诺,其结构经红外、质谱、核磁共振谱确证。其中Vilsmeier反应通过控制反应温度在-5—5℃、三氯氧磷的用量为底物的4．5mol,收率比文献提高30％;水解反应改用盐酸,收率92％。     

Dual enzyme activated fluorescein based fluorescent probe

A simple dual analyte fluorescein-based probe (PF3-Glc) was synthesised containing β-glucosidase (β-glc) and hydrogen peroxide (H₂O₂) trigger units. The presence of β-glc, resulted in fragmentation of the parent molecule releasing glucose and the slightly fluorescent mono-boronate fluorescein (PF3). Subsequently, in the presence of glucose oxidase (GOx), the released glucose was catalytically converted to D-glucono-δ-lactone, which produced H₂O₂ as a by-product. The GOx-produced H₂O_2, resulted in classic H₂O₂-mediated boronate oxidation and the release of the highly emissive fluorophore, fluorescein. This unique cascade reaction lead to an 80-fold increase in fluorescence intensity.     

A water-soluble,low-cytotoxic and sensitive fluorescent probe based on poly(ethylene glycol) for detecting sulfide anion in aqueous media and imaging inside live cells

Sulfide anions are generated not only as a byproduct from industrial processes but also in biosystems. Hence, fluorescent probes for detecting sulfide anion which are water soluble, sensitive, selective and biocompatible are highly sought-after. In this study, we report a water-soluble, low-cytotoxic and sensitive fluorescent sensor for detecting sulfide anion. In this probe, the strong electron-withdrawing dinitrobenzenesulfonate ester group is incorporated onto fluorescein fluorophore, and correspondingly the fluorescence of fluorescein is efficiently quenched; while when the dinitrobenzenesulfonate ester is cleaved by the nucleophilic sulfide anion, the substantial fluorescence enhancement can be observed. Furthermore, poly(ethylene glycol) is coupled onto the fluorophore to impart the probe water-soluble and low cytotoxicity. The probe is capable of permeating the cell membrane and realizing sulfide anion monitoring and imaging in live cells and real sample. This technically-simple modification strategy may be suitable for fabricating some other fluorescent probes with enhanced biocompatibility and water solubility.     

Transglutaminase-mediated N- and C-terminal fluorescein labeling of a protein can support the native activity of the modified protein

Fluorescein and its analogs are among the best fluorophores to label proteins and the labeling generally involves chemical modification of a translated protein. Using this methodology, labeling at a specific position remains difficult. It is known that the guinea pig liver transglutaminase (TGase)-catalyzed enzymatic modification method can allow terminal-specific fluorophore labeling of a protein by monodansylcadaverine. However, native activity of the fluorescent protein has not been investigated so far, nor has direct comparison between the chemical modification and the TGase-catalyzed modification been attempted. Therefore, we compared the possibility of fluorescein labeling via chemical labeling and via TGase-catalyzed modification. The latter method was found to be very practical and overcame some of the problems associated with the specificity of the former; fluorescein was covalently attached only to the N- or C-terminal site of glutathione S-transferase when the reaction was catalyzed by TGase and the resulting labeled protein completely retained its native activity. The TGase-mediated labeling occurred not only at room temperature but also at 4 degrees C to the same extent, which is more desirable for preventing the inactivation of proteins.     

Syntheses of pyrazole monomers

(1-Phenyl-5-methyl-pyrazolyl-4)-acetylene was prepared by treating 1-phenyl-4-acetyl-5-methyl-pyrazole with Vilsmeier complex. During the first stage of the reaction the β-(1-phenyl-5-methyl-pyrazolyl-4)-β-chloro-acroleine separated, and suffered in the presence of alkali a dechloroformylation to form the ethinylic compound. As the acroleine intermediate is an α,β-unsaturated aldehyde it can react with substituted hydrazines leading to substituted pyrazoline derivatives. The structures of the monomers were confirmed by means of IR and NMR spectral measurements. In the presence of PdCl₂ as catalyst, oligomers were obtained which have then been transformed into charge transfer-complexes. Variation of the ESR signal intensity was followed as a function of A/D ratio.     

Darstellung und Charakterisierung N-Disubstituierter 2-Amino-4-chlor-thiazol-5-aldehyde und ihrer Dicyanmethylen-Derivate

Preparation and Characterisation of N-Disubstituted 2-Amino-4-chloro-5-formyl-thiazoles and Their Dicyanmethylene Derivatives In contrast to N-disubstituted 3-hydroxy-anilines 5 which react with the Vilsmeier reagent to N-substituted 4-amino-salicylaldehydes 7 their heteroanalogous N-disubstituted 2-amino-4-hydroxy-thiazoles 6 react with the same reagent to N-substituted 2-amino-4-chloro-thiazole-5-aldehydes 12 via their corresponding iminium salts precursors 11 . Both types of compounds can be transformed, in analogy to other 2-amino-thiazole-5-aldehydes, by reaction with malodinitrile 13 into stable N-substituted 2-amino-4-chloro-5-(2,2-dicyano-ethenyl)-thiazoles 14 .