甲基红共振瑞利散射法测定多肽药物奥曲肽

采用共振瑞利散射(RRS)法测定奥曲肽,建立了测定痕量奥曲肽的方法。在pH=3.78的B-R缓冲溶液中,奥曲肽与甲基红相互作用后,共振瑞利散射显著增强,在280～370nm范围内呈现高的散射强度,且以310nm处的ΔIRRS最强。在优化的测试条件下,奥曲肽浓度在0～0.54mg/L范围内与散射强度有良好的线性关系,对奥曲肽的检出限(3σ)达3.6μg/L。该方法用于合成样品中奥曲肽的测定,回收率为98.3%～100.7%;用于奥曲肽注射液中奥曲肽含量的测定,结果与HPLC法测得的结果相近。     

高灵敏共振瑞利散射法对痕量药物奥曲肽的测定

采用共振瑞利散射法测定多肽药物奥曲肽.在pH 4.1的B-R缓冲溶液中,奥曲肽和石蕊相互作用后,共振瑞利散射显著增强,在285 ～367 nm范围内呈现高的散射强度,且以310 nm处的ΔIRRS最强.奥曲肽的质量浓度在0.007 3 ～0.45 mg/L范围内与ΔIRRS成正比,检出限(3σ)为2.2 μg/L.该法用于奥曲肽合成样品和注射液中奥曲肽含量的测定,结果满意,实现了以廉价试剂、简便方法快速测定痕量贵重药品的目的.     

乙酸奥曲肽的波谱解析

利用波谱学等技术详细研究了生长抑素类似物奥曲肽的乙酸盐的波谱学特征.1H NMR和1H-1H COSY谱分析表明该化合物由70个质子组成,与乙酸奥曲肽中氢原子数相符,说明乙酸与奥曲肽以1∶1的摩尔比形成铵盐;13C NMR及DEPT实验结果证明该化合物由51个碳原子组成,与乙酸奥曲肽中碳原子数一致;电喷雾离子源质谱(E...     

高效液相色谱法定量分析奥曲肽

建立奥曲肽的高效液相色谱定量分析方法。色谱柱为Eclipse plus C18柱(4.6 mm×250 mm,5 μm),流动相为乙腈-0.25%高氯酸水溶液(体积比为30∶70),流量为1.0 mL/min,检测波长为210 nm,柱温为25℃。奥曲肽的质量浓度在4.38~219 μg/mL范围内与色谱峰面积成良好的线性关系,相关系数为0.9999,检出限为1.1 ng,定量限为2.19 ng。测定结果的相对标准偏差为0.26%~0.46% (n=5),加标回收率为97.41%~100.26%。该方法简便、快速、准确,适用于奥曲肽原料药与制剂的定量分析。     

氨基磺酸催化合成丁二酸二丁酯

研究了氨基磺酸代替硫酸作为酯催化剂,由丁二酸与正丁醇合成丁二酸二丁酯的反应,考察了反应的影响因素及氨基磺酸的重复使用性能。丁二酸3．0g(250mmol),n(丁二酸)：n(正丁醇)：n(氨基磺酸)=1．00：8．00：0．31,回流分水60min,酯收率97．4％。另外,还催化合成了癸二酸二丁酯、己二酸二丁酯和马来酸二丁酯。     

醋酸奥曲肽治疗肝硬化失代偿期上消化道出血的临床效果观察

目的醋酸奥曲肽治疗肝硬化失代偿期上消化道出血的临床效果。方法按照随机数字表法将60例肝硬化失代偿期上消化道出血患者均分为实验组和对照组,分别采取单纯垂体后叶素和醋酸奥曲肽+垂体后叶素治疗,比较两组患者治疗效果。结果实验组患者治疗总有效率明显高于对照组,差异具有显著性(P0.05);两组患者不良反应总发生率对比,差异无统计学意义(P0.05)。结论醋酸奥曲肽+垂体后叶素治疗能够有效缩短肝硬化失代偿期上消化道出血止血时间,提高治疗效果,不良反应发生率低,临床应用价值较高。     

丁二酸双(单)异辛酯磺酸钠的合成

以马来酸酐和异辛醇为起始原料,经酯化和磺化反应制得丁二酸双异辛酯磺酸钠(1)和丁二酸单异辛酯磺酸钠(2); 1在氢氧化钠作用下经部分皂化反应合成了丁二酸单异辛酯磺酸钠(3),其结构经¹H NMR, ¹³C NMR, IR和MS(ESI)表征。     

钯催化二茂铁硼酸和有机三氟甲磺酸酯制备单取代二茂铁芳基化合物的偶联反应

在Pd(PPh3)4催化下,以K3PO4为碱,以二氧六环为溶剂,二茂铁硼酸和有机三氟甲磺酸酯在回流条件下高收率得到了单取代二茂铁的偶联产物.不同三氟甲磺酸酯的偶联反应产率在72%～92%之间.     

结合分子模拟探讨不同醚键PBS基共聚物的性能与酶催化降解

以硫二甘醇取代二甘醇,在聚(丁二酸丁二醇酯)(PBS)分子主链上分别引入硫醚和氧醚基团,得到聚(丁二酸丁二醇酯-丁二酸硫代二乙二醇酯)[P(BS-co-TDGS)]和聚(丁二酸丁二醇酯-丁二酸二乙二醇酯)[P(BS-co-DEGS)],通过热重分析(TG)和X射线衍射(XRD)测试比较了二者的结晶性能和热性能.采用南极假丝酵母脂肪酶N435(CALB)为催化剂,在水相中研究了P(BS-co-TDGS)和P(BS-co-DEGS)的降解规律及差异性.采用分子模拟方法研究了共聚物可能存在的聚集态以及N435酶与底物的结合,模拟结果验证了共聚物P(BS-co-TDGS)的结晶度下降及热稳定性降低的结论.分子对接模拟结果表明,N435酶与DEGSDEG单元的结合能更大,即含有丁二酸硫代二乙二醇酯键型底物P(BS-co-DEGS)与N435酶活性位点的对接更为稳定.     

聚(丁二酸丁二酯-co-丁二酸丙二酯)的等温结晶行为研究

以1,4-丁二酸、1,4-丁二醇和1,3-丙二醇为原料通过直接熔融缩聚法合成了聚丁二酸丁二酯(PBS),聚丁二酸丙二酯(PPS)和聚(丁二酸丁二酯-co-丁二酸丙二酯)(PBSPS)等脂肪族聚酯.利用1H-NMR,WAXD,DSC和POM等研究了聚酯的结晶结构和结晶动力学过程等结晶行为.PBSPS的结晶晶型与PBS一致,说明只有丁二酸丁二酯(BS)单元结晶而丁二酸丙二酯(PS)单元处于无定形区.聚酯等温结晶后,在升温熔融过程中出现了多重熔融峰.分析表明多重熔融峰主要来自于聚酯升温过程中的熔融-重结晶行为.利用Avrami方程分析了聚酯的等温结晶动力学,Avrami指数n为2.2~2.8,说明聚酯等温结晶时主要以异相成核的三维生长方式进行;随着PS单元的增多,聚酯的表观结晶活化能升高,也就是说BS单元的结晶变得困难.POM观察到聚酯等温结晶时都出现了环带球晶现象,球晶形态会随着结晶温度和化学结构差异而改变.     

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%.     

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.     

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.     

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.     

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 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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.