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。     

^(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。     

核磁共振氢谱内标法测定茚地普隆的含量

建立了测定无对照品的新型非苯二氮唑类镇静催眠药茚地普隆含量的快速、专属、简单的核磁共振氢谱内标法。用Varian Mercury Plus400MHz核磁共振谱仪,在25℃、以氘代氯仿为溶剂、3,4-二硝基甲苯为内标、观察频率400.121MHz、谱宽6410Hz、90°脉冲宽度6.45μs、采集时间4s和延迟时间15s的条件下采集试样的氢谱。以化学位移分别在δ8.72和δ8.72处的茚地普隆和3,4-二硝基甲苯的单峰作为定量峰,其峰面积比(As/Ar,y)与其质量比(ms/mr,x)的线性回归方程为y=6.1458x 0.0055,相关系数为r=0.99996,含量测定重复性实验的RSD为0.29%(n=6)。分析结果表明,在没有对照品的情况下,核磁共振氢谱内标法,可用于茚地普隆的含量测定和质量控制。     

核磁共振定量法测定制剂中埃索美拉唑含量

以马来酸为内标,氘代二甲基亚砜为溶剂测定1H核磁共振谱,通过比较样品定量峰与内标物质响应峰峰面积,计算埃索美拉唑的含量。结果显示,同一样品在相同条件下测定6次,定量峰与内标响应峰比值的RSD为0.54%;平行配制5份样品溶液,定量峰与内标响应峰比值的RSD为0.62%。采用不同样品定量峰计算的埃索美拉唑含量分别97.2%、97.1%、98.2%、98.1%,RSD分别为0.54%、0.62%、1.33%、1.28%。本文建立的核磁共振定量法(q NMR法)可以有效避免辅料依地酸二钠、氢氧化钠干扰,经方法验证可用于测定埃索美拉唑含量。     

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。     

生物质合成气一步法合成二甲醚的在线分析系统

建立了一套由生物质合成气一步法制取二甲醚的在线分析系统.针对生物质合成气一步法合成二甲醚特征,采用两台分别装有TCD和FID检测器的色谱仪分析反应产物.利用原料气中N2作为内标物,来确定TCD上检测到的永久性气体组分浓度;通过CH4作内标物,来确定FID上检测到的有机物组分浓度.TCD和FID之间通过CH4来关联,从而确定反应产物中主要组分的浓度.该系统在压力3 MPa,温度250℃,空速(流速与催化剂体积的比值)分别为1 000、2 000、3 000 h-1的条件下用C306和HZSM-5催化剂进行评价测试,发现系统分析效果好,重复性高,并且反应前后主产物碳平衡到达90%以上.     

高效液相色谱法测定中药材补骨脂中补骨脂素和异补骨脂素的含量

 建立了测定中药材补骨脂中补骨脂素和异补骨脂素含量的高效液相色谱法。采用的色谱条件为:Hypersil ODS色谱柱(150 mm×4.6 mm i.d., 5 μm),以乙腈-水(体积比为30∶70)为流动相,检测波长为245 nm。在此条件下,补骨脂素、异补骨脂素和内标物联苯苄唑获得了较好的分离。补骨脂素和异补骨脂素质量浓度分别为0.50～10.0 mg/L 时,组分与内标的峰面积比值与质量浓度之间的线性关系良好(r=1.000),最低检测限为10 μg/L (S/N=3) 。所建立的方法用于不同     

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。     

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。     

核磁共振法测定依帕列净含量

分别以盐酸吉西他滨和齐多夫定为内标,采用定量核磁共振法对依帕列净含量进行测定。以氘代二甲亚砜和重水混合液为溶剂,确定氢定量核磁共振方法(1H-q NMR)的测试条件为:激发脉冲角度30°;时间域数据点32 K;测定温度303 K;脉冲延迟时间20 s;采样次数32;窗函数0.3 Hz。在此实验条件下,结果专属性良好,稳定性可达24 h,耐用性符合要求。以样品与内标的峰面积比对其摩尔比绘制标准曲线,结果显示,依帕列净与内标盐酸吉西他滨的摩尔比在0.512 5~1.953 8范围内,依帕列净与内标齐多夫定的摩尔比在0.494 7~1.966 0范围内线性关系良好,相关系数(r2)均为0.999 9。以盐酸吉西他滨和齐多夫定为内标时,依帕列净的含量测定结果分别为99.83%和99.77%,相对标准偏差(RSD)分别为0.06%和0.19%。2种内标方法的测定结果一致,所建立的方法专属、准确、简便、快捷,适用于新药的含量测定。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.