柱前衍生化-HPLC法分析不同产地厚朴叶多糖的单糖组成

建立了1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化-高效液相色谱法(HPLC)同时测定厚朴叶多糖中的6种单糖含量的方法。采用Phenomenex(4.6 mm×250 mm, 4μm)为色谱柱，流动相为0.2%磷酸溶液-乙腈(体积比为82∶18),流速为1.0 mL/min,检测波长为245 nm,柱温为35℃。结果显示，基于HPLC法所建立的单糖检测方法，6种单糖成分在各自线性范围内线性关系良好(R²≥0.9994),平均加标回收率为97.17%～100.22%,相对标准偏差(RSD,n=6)为1.67%～2.82%。16批不同产地厚朴叶单糖组成相似，主要是由葡萄糖、甘露糖、半乳糖、鼠李糖和阿拉伯糖组成。主成分分析结果显示，湖北和重庆样品间的单糖组成得到明显区分。该试验所建立的方法操作简便，重复性和准确度高，适用于厚朴叶多糖中单糖成分的含量测定。     

单糖与苯硼酸的酯化反应及生物应用简介

讲述了单糖与苯硼酸间的酯化反应过程及影响因素,举例说明了此类反应在化学和生物学中的应用,拓展了有机化学教学中关于单糖化合物的应用介绍,引导学生提升对化学和生物学交叉领域学习和研究的兴趣。     

柱前衍生化高效液相色谱法分析多糖中的单糖组成

报道了多糖中单糖组成的柱前衍生化高效液相色谱测定方法。采用反向高效液相色谱250nm紫外检测和使用梯度洗脱，6种还原单糖的1－苯基－3－甲基－5－吡唑啉酮衍生实现了良好的分离并具有良好的峰形。对单糖组成的定量测定进行了方法学考察，建立了单糖组成分析的数据分析方法，并用所建立方法对一个多糖中的单糖组成进行了分析，获得良好的重复性。     

柱前衍生化-高效液相色谱法分析木糖结晶母液的单糖组成

采用1-苯基-甲基-吡唑啉酮(PMP)柱前衍生化-反相高效液相色谱(HPLC)法建立了8种常见单糖的分离模式,并用于木糖结晶母液单糖组成的定量分析.结果表明:木糖结晶母液至少由甘露糖、鼠李糖、纤维二糖、葡萄糖、半乳糖、木糖、阿拉伯糖及岩藻糖8种单糖组成,其中以葡萄糖、半乳糖、木糖和阿拉伯糖为主.以峰高定量,8种单糖的浓...     

柱前衍生化-高效液相色谱法分析缅甸刺梧桐胶多糖的单糖组成

利用1-苯基-3-甲基-5-吡唑啉酮柱前衍生化-高效液相色谱法,优化10种常见单糖的色谱分离条件,并用于不同等级的自制刺梧桐胶多糖的单糖组成分析。对自制刺梧桐胶多糖的单糖组成分析结果表明,自制刺梧桐胶多糖由葡萄糖醛酸(GlcUA)、鼠李糖(Rha)、半乳糖醛酸(GalUA)、半乳糖(Gal)、阿拉伯糖(Ara)和岩藻糖(Fuc) 6种单糖组成,平均物质的量比为1∶3.30∶1.62∶2.45∶0.08∶0.03。对不同等级的刺梧桐胶多糖的分析鉴定结果表明,不同等级的刺梧桐胶多糖的单糖组成均含Rha、GalUA、GlcUA、Gal 4种单糖组分,其中Ara在缅甸A、B级中没有检测出来,Fuc在缅甸D级中没有检测出来。方法学结果显示:10种单糖在各自线性范围内线性关系良好,相关系数r≥0.9992,6种单糖加标回收率在96.80%～101.26%之间,相对标准偏差小于3%。该方法简单、准确灵敏,可用于刺梧桐胶多糖的单糖组成分析。     

毛细管柱气相色谱法测定银杏叶中可溶性单糖

采用恒温水浸泡提取可溶性单糖,所得浸出液经减压蒸发(60℃)干燥后用二甲基亚砜(DMSO)作溶剂使残渣溶解,六甲基二硅烷(HMDS)和三甲基氯硅烷(TMCS)作硅烷化试剂,将单糖衍生化为三甲基硅烷衍生物,以肌醇为内标物,用SE-30毛细管色谱柱,气相色谱法测定了银杏叶中7种单糖含量,测定标准偏差小于10%.同时测定了春秋两季所采摘的样品以及从叶柄的所采样品中的单糖含量.试验结果表明:春季银杏叶中各单糖含量均高于秋季黄叶,春季银杏叶叶柄中除果糖外均高于叶中各单糖含量.     

单糖结构及其旋光度的计算

根据螺旋理论的规律，对常见单糖及其甲甙的旋光度进行了计算。计算结果和测定值相当接近，在旋光方向上完全一致，旋光度数值也都在可接受的误差范围之内。证明单糖及其甙的立体结构和旋光性的关系是十分密切的。根据糖和糖甙的立体结构，可以推断旋光方向和旋光度的大小，反之，从旋光性也可以推断单糖及其甲甙的立体结构。     

不同加工方式对鹿茸中水溶性多糖含量及单糖组成的影响

采用水提醇沉法提纯鹿茸中的水溶性多糖，苯酚-硫酸法测定其含量；多糖经水解、衍生后通过UPLC分析不同加工方式及不同部位鹿茸中单糖组成及含量的差异。结果表明，煮炸茸蜡片、粉片、纱片、骨片中水溶性多糖含量分别为1.74、1.67、1.03和1.13 g/kg，冻干茸为2.77、3.07、1.22和3.20 g/kg；排血茸4个部位水溶性多糖含量依次为1.55、1.78、0.96和0.77 g/kg，带血茸为1.69、1.64、1.01和1.31 g/kg。不同加工方式鹿茸中水溶性多糖单糖组成均检出甘露糖、氨基葡萄糖、核糖、葡萄糖醛酸、半乳糖醛酸、氨基半乳糖、葡萄糖和半乳糖8个组分，对于同一部位，煮炸茸单糖含量低于冻干茸，排血茸单糖（氨基葡萄糖和氨基半乳糖除外）含量低于带血茸；对于同一加工方式不同部位，表现出蜡片、粉片高于纱片、骨片。研究加工方式对鹿茸中水溶性多糖含量及单糖组成的影响，以期为鹿茸加工及其产品开发提供理论参考。     

气相色谱法测定芦荟及芦荟干粉中的多糖

提取芦荟及芦荟干粉样品中的多糖，将多糖水解为单糖之后衍生化反应，用气相色谱法进行分析，实验选择了最佳分离条件，以木糖醇为内标物，用OV-225与OS-138为色谱柱固定液，使衍生物得到了很好的分离，结果表明：未经水解的芦荟中含有少量的单糖以葡萄糖的形式存在，水解后的单糖主要为甘露糖和葡萄糖，这与用乙醇沉淀多糖后测定结果一致，即芦荟及芦荟干粉中的多糖主要为甘露聚糖和甘露葡聚糖。     

离子色谱-脉冲安培法测定芦荟多糖中7种单糖的含量

采用水提醇沉法提取芦荟鲜叶中的多糖，经三氟乙酸水解，利用Dionex CarboPac PA10高效阴离子色谱柱分离，氢氧化钠梯度淋洗，积分脉冲安培检测，建立了芦荟多糖中岩藻糖、鼠李糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖和木糖7种常见单糖的测定方法。结果表明：7种单糖在线性范围内的相关系数（R²）均高于0.997，检出限为0.007~0.024 mg/L，加标回收率为97.5%~102.5%，相对标准偏差（RSD）为0.1%~4.8%。该法简单、快速、灵敏、准确，可用于芦荟多糖中单糖含量的测定和多糖组成的研究。     

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.