3,4-二氨基苯基苯甲酮在基质辅助激光解析离子化质谱分析磷脂中的应用

考察了3,4-二氨基苯基苯甲酮(DABP)作为基质辅助激光解吸离子化飞行时间质谱(MALDI-TOF-MS)新型基质分析磷脂的能力.与传统基质2,4,6-三羟基苯乙酮(THAP)、2,5-二羟基苯甲酸(DHB)、α-氰基-4-羟基肉桂酸(CHCA)相比,用优化后的DABP基质溶液体系McOH-H2O-HCI(80:20...     

碲化镉量子点用于基质辅助激光解吸电离飞行时间质谱分析全氟化合物

考察了CdTe量子点作为新型无机基质,应用于基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)法分析全氟辛烷磺酸(PFOS),全氟癸烷磺酸(PFDS),全氟己烷磺酸(PFHxS)和全氟庚烷磺酸(PFHpS)4种全氟化合物(PFCs)的效果;同时与传统有机基质α-氰基-4-羟基桂皮酸(CHCA)、1,8-双二甲氨基萘(DMAN)进行比较.实验中,分别将目标分析物与基质溶液滴于样品板上并混合均匀,待自然蒸干溶剂后形成结晶状,采用337 nm波长紫外激光辐照激发,在负离子模式条件下MALDI-TOF-MS分析检测.此外,简要探讨了CdTe量子点颗粒激光辅助解吸离子化的机理.结果表明,CdTe量子点颗粒,具有较强紫外吸收,可直接作为无机基质用于以上4种全氟化合物的MALDI-TOF-MS分析,并且具有提高待测物质谱峰强度等特点.     

聚芳醚酮环状低聚物的基质辅助激光解吸电离质谱表征

采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术分别对2种合成的聚芳醚酮环状低聚物进行了分析研究 ,并讨论了低聚物中不同聚合度离子组分的分布规律。实验结果表明MALDI-TOF-MS是分析环状低聚物直观、准确、快速的分析工具。     

基质辅助激光解析飞行时间质谱快速测定水解胶原蛋白粉分子量

应用基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)快速测定了水解胶原蛋白粉的分子量.分别以α-氰基-4-羟基内桂酸、2,5-二羟基苯甲酸和芥子酸为基质,在正离子模式下对水解胶原蛋白粉分子质量分布进行测定.结果显示:芥子酸为最适宜基质,分析条件为线性方式和反射方式相结合,可准确、快速确定水解胶原蛋白粉的分子...     

介孔沸石材料负载传统基质用于激光解吸电离-飞行时间质谱分析小分子化合物

考察了介孔沸石材料负载传统有机基质α-氰基-4-羟基桂皮酸(CHCA)用于基质辅助激光解吸电离-飞行时间质谱(MALDI-TOF-MS)分析多肽Substance P和氟喹诺酮类药物等小分子的效果.在相同的MALDI-TOF-MS质谱条件下,与传统CHCA进行了比较,同时分别考察了不同硅铝比(SiO2/Al2 O3)的ZSM-5以及不同介孔大小的Beta与ZSM-5沸石载体对Substance P的检测效果.结果表明,沸石负载CHCA新型复合基质具有抑制碱金属离子峰、消除干扰碎片离子、简化与改善质谱图、提高离子化效率等优点.实验结果表明,沸石表面酸性越强,有力介孔能够充分包裹CHCA分子,则复合基质抑制干扰碎片和提高离子化效率的能力越高.复合基质成功应用于复杂样品中恩诺沙星与诺氟沙星药物小分子的MALDI-TOF-MS检测.     

应用激光解吸质谱和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析蛇毒精氨酸酯酶的纯度和分子量

应用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)和SDS-聚丙烯酰胺凝胶电泳对吉林省两地市的同种白眉蝮蛇蛇毒中具有抗栓塞药效的精氨酸酯酶进行了分析和比较。MALDI-TOF-MS法具有快速、准确度高、灵敏度高的优点,两种方法结合,互为补充,取得了令人满意的结果,MALDI-TOF-MS完全可以直接用作蛇毒成分分离过程中重要的研究手段。     

碱量法测定壳聚糖脱乙酰度的研究

碱量法(包括酸碱滴定法和电位滴定法)是目前测定壳聚糖脱乙酰度较为常用的方法,其原理是用过量的稀酸与一定量的待测壳聚糖反应,然后用标准NaOH溶液滴定过量的酸来测量壳聚糖中自由氨基的量,从而计算壳聚糖的脱乙酰度(DD值)。计算脱乙酰度的公式多用:DD=(-NH2)%/0.094×100%(公式一)。而另外一个碱量法中未用过的脱乙酰度计算公式为:DD=[203n/(G 42n)]×100%(公式二),本文用计算公式一和公式二分别计算在酸碱滴定法和双突跃电位滴定法中壳聚糖的脱乙酰度,结果表明:在酸碱滴定法中,用公式一的计算的结果准确度更高,而在双突跃电位滴定法中用公式二计算的结果准确度更高。     

高效辅助激光解吸/电离聚合物的新基质α-腈基阿魏酸在飞行时间质谱中的应用研究

以α-腈基阿魏酸(CFA)为基质,利用基质辅助激光解吸离子化飞行时间质谱法(MALDI-TOF-MS)对新合成的聚合物A和B进行分析,获得了聚合物的相对分子量、分子量分布、重复结构单元以及末端基结构等信息。与常用基质2,5-二羟基苯甲酸(DHB)、α-氰基-4-羟基肉桂酸(HCCA)、芥子酸(SA)和蒽三酚(DIT)等几乎不能解吸/电离聚合物A和B的结果相比较,CFA展现出优越的基质性能,获得了分辨率和信噪比较高的聚合物质谱图,为聚合物分析提供了丰富的信息,并为该类聚合物合成反应条件的优化和反应机理的推导提供确凿依据。     

不同脱乙酰度对壳聚糖表面物理及吸附性能的影响

壳聚糖是甲壳素部分脱乙酰化的产物,脱乙酰度的大小对壳聚糖的性能影响很大。利用碱液法,通过对反应时间的控制,制备了不同脱乙酰度的壳聚糖并对其性能进行了研究。结果表明,随着脱乙酰度的增大,壳聚糖膜的吸水率增加,而对其表面接触角的变化则没有影响。同时,壳聚糖海绵对Ca2+和牛血清蛋白(BSA)的吸附能力也随着脱乙酰度的增大而增加。     

完全脱乙酰化壳聚糖与Zn(Ⅱ)的配位作用

在均相反应条件下 ,完全脱乙酰化的壳聚糖与ZnSO4 进行配位反应 .用元素分析、IR、固体13 C NMR、UV vis、TGA和X 衍射等表征方法研究了Zn(Ⅱ )与壳聚糖所形成配位聚合物的组成和结构 .在pH =7时 ,一个Zn(Ⅱ )与二个壳聚糖重复单元中的氨基和仲羟基进行了配位     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.