姬松茸低聚肽的制备及性质

采用超临界CO2萃取对姬松茸进行脱脂处理后, 用微波提取姬松茸多糖, 以脱脂脱多糖的姬松茸为原料, 采用双酶法制取姬松茸低聚肽, 并对姬松茸低聚肽的抗氧化能力进行了研究. 结果表明, Alcalase 2.4L碱性蛋白酶的最佳酶解条件为: pH=8.5, 温度55 ℃, 酶解时间2 h, 底物浓度5％, 酶用量1.5％, 肽得率为74.7%. Flavourzyme风味蛋白酶最佳酶解的条件为: pH=7.0, 温度50 ℃, 时间1.5 h, 酶用量为4％, 最终肽得率为80.6%. 姬松茸低聚肽分子量集中在5600以下, 人体必需氨基酸含量为50.91%(质量分数). 姬松茸低聚肽对邻苯三酚自氧化具有明显的抑制作用, 抑制率为35.6%.     

苦丁茶中总黄酮的三波长-光谱法定量分析

采用三波长 分光光度法测定苦丁茶中有效化学成分黄酮的含量 ,有效地消除了吸收峰不对称给定量分析能造成的影响 ,并校正了基于干扰组分 (饮料中添加剂等 )的吸收光谱具有可能是散射造成的背景线性吸收产生的基线倾斜。回归方程为 :ΔA =- 3.70 2× 1 0 -3 +3.70 2 3C ,相关系数r =0 .9994 ,黄酮的浓度在6 0 0～ 1 6 0 0mg/L范围内 ,分别在波长为λ1 =4 70nm ,λ2 =4 2 0nm ,λ3 =370nm处测吸光度时 ,则ΔA与浓度C之间呈良好的线性关系 ,可按标准曲线法进行定量分析。方法的回收率为 98%～ 1 1 2 % ,相对标准偏差小于1 1 4 %。方法的准确度与精密度均令人满意 ,而且操作简便易行     

高效液相色谱法测定恩替卡韦口服液中有关物质

建立了测定恩替卡韦口服液中有关物质的高效液相色谱法。采用Agilent ZORBAX SB-C18色谱柱,以水-乙腈-三氟乙酸(97∶3∶0.15,V/V)/乙腈为流动相,梯度洗脱,二极管阵列检测器(DAD)检测。杂质A、B和C的检测限分别为7.22ng/mL、7.30ng/mL和7.50ng/mL,分别相当于恩替卡韦浓度的0.014%、0.015%、0.015%;杂质A在24.08~361.0ng/mL浓度范围内(r=0.9988),杂质B在24.33~364.9ng/mL浓度范围内(r=0.9996),杂质C在25.00~375.0ng/mL浓度范围内(r=0.9984)呈现良好的线性关系;在0.125、0.25、0.37μg/mL三个浓度的添加水平下,杂质A、B、C的平均回收率分别为121.9%、115.5%和106.9%。     

金银花中绿原酸的微波预处理提取及检测

采用微波预处理法对金银花中绿原酸的提取进行优化,用三波长法测定了绿原酸的含量.设计正交试验,以绿原酸的含量为指标,考察乙醇用量、乙醇浓度和微波处理时间对金银花中绿原酸提取工艺的影响.三波长法检测波长为λ1=280 nm,λ2=325 nm,λ3=380 nm,其回归方程为ΔA=0.0426C 0.0017,相关系数为R=0.998.结果表明在气化剂用量20 mL,乙醇浓度为70(,微波辐射70 s时绿原酸得率最高.与常用的提取和测定方法相比,此方法对设备要求不高,具有更高的准确性与精密度.     

高效液相色谱法测定头孢他啶的含量及杂质

采用高效液相色谱法测定了头孢他啶的含量及杂质。以Alltima C18色谱柱(250 mm×4.6 mm,5 μm)为分离柱,以乙腈和磷酸盐缓冲溶液(pH 3.9)分别为流动相A和流动相B进行梯度洗脱,流速1.3 mL/min,柱温35 ℃,紫外检测波长255 nm。从头孢他啶药物中共分出14个杂质,且14个杂质间具有良好的分离度。头孢他啶在0.267~1069 μg/mL范围内与峰面积具有良好的线性关系(r=1.0000);其定量限(S/N=10)和最低检出限(S/N=3)分别为3.1 ng和0.93 ng。3个浓度的日内测定值的相对标准偏差(RSD）为0.72%(n=3),日间测定值的RSD为0.91%(n=3)。头孢他啶溶液在4 ℃避光条件下放置24 h保持稳定。本方法与欧洲/英国药典和日本药局方的方法比较,具有分离杂质数量多、分离度好的优点。     

紫外分光光度法测定蒙药漏芦花中总黄酮含量

用紫外分光光度法测定蒙药漏芦花中总黄酮含量.以芦丁为对照品,在波长510nm处对样品中的总黄酮含量进行测定.样品总黄酮在浓度0～50μg/mL范围内线性关系良好,其回归方程为:A=0.0128C+0.0064,R=0.9995;平均加样回收率98.54%,RSD为1.320%(n=5).该方法稳定、简便、准确,可用于漏芦花中总黄酮含量的测定.     

光谱法测定复方双氯灭痛注射液含量

本实验对复方双氯灭痛注射液中扑热息痛和双氯灭痛两种主要成分分别采用双波长紫外分光光度法及紫外差示分光光度法进行含量测定。可在不用分离的情况下连续测定两种成分的含量。实验结果:扑热息痛的直线回归方程C=31.34A+0.078,R=0.9999,回收率100.69%,CV%=0.91。双氯灭痛的直线回归方程C=24.94A—0.202,R=0.9997,回收率为100.91%,CV%=0.77。本法具有方法简便,结果准确,重现性好,实用等优点。     

铬黑T流动注射法在线测定水样中的微量Ni(Ⅱ)

利用铬黑T(EBT)与镍(Ⅱ)发生显色反应,生成一种紫罗兰色的配合物,建立了新的在线分析镍的流动注射法。在pH为10的H2B4O7-KCl-NaOH缓冲溶液中,铬黑T用量2.5 mL,缓冲液用量2.5 mL,灵敏度最好。方法的线性范围为10～1000μg·L-1,在10～100μg·L-1浓度范围内,ΔA=0.4234C+3.4336,R2=0.9998;在100～1000μg·L-1浓度范围内,ΔA=0.3907C+12.869,R2=0.9985,线性关系良好。检出限(3S/N)为3.4μg·L-1,加标回收率在98.8%～104.2%之间,相对标准偏差(n=14)为1.82%(200μg·L-1的镍标液),结果令人满意。     

桦褐孔菌子实体和发酵菌丝体中甾类化合物的定量测定

建立了采用高效液相色谱(HPLC)定量测定桦褐孔菌子实体和发酵菌丝体中白桦脂醇、麦角甾醇、胆甾醇、羊毛甾醇、豆甾醇和谷甾醇含量的方法。色谱条件: 以C18柱进行分离,流动相为不同浓度梯度的水-甲醇(0~10 min,体积比为10:90;10~40 min,体积比为3:97),流速为1.4 mL/min,检测波长为202 nm,整个分析在40 min内完成。结果表明所建立的方法具有很好的重复性和回收率。甾类化合物分析测定的日内相对标准偏差为2.10～2.94%(n=5),在0.4～4.8 μg范围内有很好的线性关系。白桦脂醇、麦角甾醇、胆甾醇、羊毛甾醇、豆甾醇和谷甾醇的回收率分别为100.05%～100.72%,99.31%～101.04%,97.52%～101.63%,96.61%～100.08%,96.21%～100.76%和100.04%～100.51%。本方法可快速、准确地定量测定桦褐孔菌子实体和发酵菌丝体中的甾类化合物。     

反相高效液相色谱法分析禾谷丝核菌菌丝中麦角甾醇和羊毛甾醇的含量

采用反相高效液相色谱法,建立了检测禾谷丝核菌中麦角甾醇和羊毛甾醇含量的方法.样品经过破碎、离心、皂化后定量测定.采用DiamonsilTMC18色谱柱(250 mm×4.6 mm i.d, 5 μm i.d.),流动相为100%甲醇,流速为1 mL/min,紫外检测波长为210 nm,保留时间定性,外标法定量.麦角甾醇和羊毛甾醇的保留时间分别为21 min和27min.麦角甾醇在0.125～12.5 mg/L、羊毛甾醇在0.1～10.0 mg/L 范围内,两者峰面积与浓度均呈线性关系,相关系数分别为0.9993和0.9983.添加回收率实验表明,2种甾醇的平均添加回收率为91.8%～99.7%;相对标准偏差为2.8%～7.8%;麦角甾醇和羊毛甾醇的最小检出量分别为1.0和0.8 ng,最低检出浓度分别为0.05和0.04 mg/L.本方法准确、简便、重现性好.     

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.