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.     

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。     

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。     

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。     

高效液相色谱法研究啶菌噁唑对番茄灰霉病菌麦角甾醇生物合成的影响

啶菌噁唑是我国研制的一种新型农用杀菌剂。本实验建立了高效液相色谱法定量分析灰霉病菌麦角甾醇含量的方法,研究了该药剂对番茄灰霉病菌麦角甾醇合成的抑制作用。结果表明,此方法具有良好的准确度和精密度,回收率为98.8%;相对标准偏差为3.0%,适用于测定番茄灰霉病菌麦角甾醇含量;番茄灰霉病菌菌丝在不同浓度啶菌噁唑和对照药剂戊唑醇处理下,药剂对其麦角甾醇合成具有明显的抑制作用,其中在0.5、10.0mg/L啶菌噁唑作用下,菌丝麦角甾醇含量分别为1.59(±0.126)和0.10(±0.011)mg/g干重菌丝,与DMIs类杀菌剂戊唑醇处理相比,没有显著性差异;与空白对照相比,抑制率分别达到22.44%和95·12%;回归分析表明,药剂处理浓度对数与麦角甾醇含量抑制率的机率值表现出正相关线性关系。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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 substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.