^(1)H和^(19)F核磁共振定量法测定诺氟沙星标准品的绝对含量EI北大核心CSCD

采用^(1)H和^(19)F核磁共振定量法测定诺氟沙星标准品的绝对含量。^(1)H核磁共振定量法以DMSO-d6为溶剂,诺氟沙星峰(δ7.9)为定量峰,马来酸峰(δ6.3)为内标峰。在脉冲程序zg30,采样时间4.09 s,延迟时间20 s,扫描次数为16的条件下采集氢谱。^(19)F核磁共振定量法以利培酮为内标物,诺氟沙星峰(δ-121.3)为定量峰,利培酮峰(δ-109.9)为内标峰。在脉冲程序zgfhigqn.2,延迟时间7 s,扫描次数为16的条件下采集氟谱。^(1)H和^(19)F核磁共振定量法测定结果接近,且与质量平衡法测定结果一致。核磁共振定量法可用来测定诺氟沙星绝对含量,快速、简单高效、且不需要对照品。     

核磁共振定量法测定利培酮含量

采用氢核磁共振定量法和氟核磁共振定量法测定利培酮含量。氢核磁共振定量法以利培酮δ7.29~7.35处质子峰为定量峰,马来酸δ6.02处为内标峰,在恒温300 K,采样时间4.0 s,弛豫延迟时间15 s,扫描次数为32次条件下采集氢谱。氟核磁共振定量法以4-溴-2-氟-乙酰苯胺为内标,在恒温300 K,谱宽12 500.0 Hz,中心频率-43 662.7 Hz下采集氟谱。测试结果显示,利培酮氢核磁共振定量法和氟核磁共振定量法的含量测定结果基本与质量平衡法的结果一致。因此,核磁共振法可用于利培酮绝对含量的测定,具有快速、简单、准确的优势。     

反门控去耦技术-定量核磁共振法测定染料木素的含量北大核心CSCD

以香草扁桃酸为内标物,提出了测定染料木素的定量核磁共振法(qNMR).采用反门控去耦模式采集氢谱,驰豫延迟时间为40 s,扫描次数为32次,采集时间为4.0 s,溶剂为氘代二甲亚砜,以染料木素中化学位移(δ,×10^(-6))6.38的峰为定量峰,香草扁桃酸中δ6.96为内标物信号峰.结果表明,染料木素与内标物香草扁桃酸的质量比在0.83~7.50内,与其定量峰和内标物信号峰的峰面积比值呈线性关系,检出限(3.3s/k)为0.2 g􀅰L^(-1).在精密度试验中,测定值的相对标准偏差(n=6)均小于0.35%;稳定性试验显示供试品溶液在避光条件下24 h内稳定.方法用于实际样品的分析,测定结果与国家标准GB/T 23788-2009的一致.     

二醇酯类内给电子体纯度的核磁共振氢谱内标法测定

建立了测定无对照品的新型二醇酯类内给电子体(6#酯、7#酯)纯度的核磁共振氢谱内标测定法。实验以氘代氯仿为溶剂,以苯甲酸甲酯标准物质为内标,设定合适的采样时间和延迟时间,选取适合的内标峰和样品定量峰,方法测定结果的相对标准偏差分别为0.31%和0.37%(n=6),且呈现良好的线性关系。样品经测量后的纯度平均值分别为98.6%和98.4%,与HPLC法测定结果符合。在没有标准对照品的情况下,核磁共振氢谱内标法可用于该二醇酯类内给电子体的纯度测定。     

核磁共振波谱法测定依非韦伦含量

分别采用氢核磁共振定量法和氟核磁共振定量法测定依非韦伦含量。氢核磁共振定量法以依非韦伦δ1.58～1.65处质子峰为定量峰,马来酸δ6.22处为内标峰。氟核磁共振定量法以δ-80.58处作为定量峰,4-溴-2-氟-乙酰苯胺δ-121.70作为内标峰。通过比较依非韦伦的定量峰与内标物质内标峰峰面积,计算依非韦伦的含量。测试结果显示,氢核磁共振定量法和氟核磁共振定量法的含量测定结果基本一致。因此,核磁共振法可用于依非韦伦绝对含量的测定,具有快速、准确的优势。     

定量核磁共振氢谱法测定枸橼酸托法替布片的有效含量

建立了枸橼酸托法替布片中有效含量的定量核磁共振氢谱测定方法。以托法替布化学位移δ 7.13为定量峰,3,5-二甲基吡唑化学位移δ 5.73为内标峰,氘代二甲亚砜（DMSO-D6）为溶剂,使用核磁共振谱仪采集混合物的氢谱,对枸橼酸托法替布片中的有效成分进行定量测定。该方法专一性强,在0.793～7.925 mg/mL范围内呈现良好的线性关系（r2=0.998 4）。精密度、重复性和稳定性的相对标准偏差（RSD）分别为0.82%、1.7%和0.67%。该方法测得的枸橼酸托法替布片中托法替布的质量分数为2.25%,其结果与高效液相色谱法基本一致。定量核磁共振氢谱法具有操作方便简单,可同时进行定性与定量,检测时间短,无需对照品等优势,可用于枸橼酸托法替布片有效含量的测定。     

维生素B2的NMR含量测定

建立了维生素B2片剂中维生素B2含量的核磁共振测定方法。核磁共振的测定条件:脉冲程序为cpmgpr1d,氢谱宽度为6 009 Hz,脉冲宽度为11.95μs,延迟时间为6.50μs,采样温度为27℃,采样次数为32次。以参比物质3-(三甲基硅基)氘代丙酸钠(TSP)为内标,将不同浓度标准品与内标的NMR峰面积比对维生素B2浓度绘制标准曲线,结果显示,维生素B2在1.25~10 mg/mL范围内呈良好线性,其线性方程为:y=2.989 4 x+0.185 5,r2=0.999 2。方法的加标回收率为83.2%。该方法灵敏度高、重现性好、操作简便,可用于维生素B2片剂中维生素B2含量的测定。     

定量核磁共振法测定一清胶囊和三黄片中的黄芩黄酮总量

用定量NMR方法建立一清胶囊和三黄片两种中成药中黄芩黄酮总量的测定方法。选择内标为邻苯二甲酸氢钾,以其谱峰(δ8.20)为内标峰,待测物定量峰的化学位移在δ8.08处,溶剂为氘代DMSO。通过考察NMR实验条件的影响,选择采样次数NS为128次,延迟时间D1为1.0 s,脉冲宽度P1为3.0μs。通过对样品中主要中药成分的浸膏和辅料的NMR实验测定,显示这两种中成药中的其它中药成分和辅料不干扰定量峰的测定。用对照品评价的(样品/内标)质量比对NMR峰面积比的零截距标准曲线斜率与理论值非常接近,相关系数R=0.999998,显示可以用2010版中国药典的核磁共振绝对定量法计算两种中成药中黄芩黄酮的总含量。对一清胶囊样品中黄芩苷的加标回收率在99.7%~100.2%,溶液稳定。并实际测定了一清胶囊和三黄片两种复方中药的6个样品中黄芩苷类似物的总含量。本法可用于一清胶囊和三黄片两种中成药中黄芩黄酮总量的测定。     

N催化剂中活性组分的核磁共振氢谱定量研究

建立了测定无对照品的N催化剂中活性组分含量的核磁共振氢谱内标测定法。以氘代甲醇为溶剂,对苯二酚为内标物,设定合适的采样时间和延迟时间,选取适合的内标峰和样品定量峰。采用优化后的实验参数进行定量分析,经计算得其中的活性组分磷酸三丁酯(TBP)、邻苯二甲酸酐开环产物(PA-DCPTi Cl3)、环氧氯丙烷开环产物(DCP-Ti Cl3)和邻苯二甲酸正丁酯(DNBP)的质量分数分别为0.21%、0.58%、1.21%和5.82%,相对标准偏差(RSD)分别为0.75%、0.89%、0.41%和0.35%,其结果的重复性和可靠性良好,与高效液相色谱法测定结果一致。该方法具有无需标准对照品、快速、高效等特点,在利用核磁共振技术研究N催化剂中活性组分的化学结构时可同时测定其含量,为催化剂中给电子体含量的表征建立了新途径。     

核磁共振波谱法测定胆酸甲酯的含量

采用核磁共振波谱法测定胆酸甲酯的含量。以顺丁烯二酸为内标,氘代二甲基亚砜和重水为溶剂,测试温度为298K,脉冲宽度为8μs,弛豫时间为50s,扫描次数为16次。δ6.28为顺丁烯二酸的定量峰,δ3.79和δ0.59为胆酸甲酯的定量峰,以两个定量峰试验结果的平均值计算胆酸甲酯的含量。顺丁烯二酸与胆酸甲酯的定量峰不受其他信号干扰,顺丁烯二酸与胆酸甲酯的质量比在0.208~1.03范围内呈线性。胆酸甲酯的绝对含量测定结果为99.4%,测定值的相对标准偏差(n=6)为0.33%。     

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.