黄姜中薯蓣皂苷元的薄层扫描法测定

采用瑞士CAMAG Scanner 3薄层扫描仪对黄姜中的薯蓣皂苷元进行测定,以V(石油醚)∶V(氯仿)∶V(甲醇)=10∶10∶0.5为展开剂,用20 g/L磷钼酸无水乙醇溶液喷雾显色,140℃烘烤约5 min,检测波长650 nm,狭缝尺寸为6.00 mm×0.30 mm。结果表明:薯蓣皂苷元在0.3~1.8μg的范围内与峰面积呈良好线性关系,相关系数r=0.9983,回收率为96.94%(n=5)。     

薯蓣皂苷元抗肿瘤衍生物的合成及其生物活性的研究

以薯蓣皂苷元为先导物,设计并合成了9个新的薯蓣皂苷元含氮衍生物,其结构经过~1H NMR,~(13)C NMR,IR和HRMS鉴定.所有衍生物采用噻唑蓝(MTT)法进行抗肿瘤活性(A549,A431,H1975,HCT-116,Aspc-1,Ramos)的测定以及细胞毒性(HBE,LO-2)的研究.研究结果表明,大部分薯蓣皂苷元衍生物具有显著的抗肿瘤活性和低细胞毒性.     

薯蓣皂苷元提取方法研究进展

薯蓣皂苷元是薯蓣皂苷的水解产物,它是许多重要甾体激素的前体物质。总结了薯蓣皂苷元提取方法的研究现状,对不同的提取工艺进行了比较。     

指纹图谱结合化学模式识别评价吉祥草的质量以及高效液相色谱法测定吉祥草中4种化学成分的含量北大核心CSCD

基于吉祥草高效液相色谱(HPLC)指纹图谱,结合化学模式识别评价20批吉祥草(S1~S20)的质量,并测定其中芦丁、人参皂苷Rb1、薯蓣皂苷、薯蓣皂苷元等4种化学成分的含量。吉祥草样品经75%(体积分数)乙醇溶液回流提取2次,过滤、合并滤液、旋转蒸发至干,得到的残渣用甲醇溶解并定容至10 mL,过0.45μm微孔滤膜,滤液供HPLC分析。采用中药色谱指纹图谱相似度评价系统(2012A版)建立20批吉祥草HPLC指纹图谱,并对其进行相似度评价。结合化学模式识别,进行聚类分析、主成分分析和偏最小二乘判别分析,并筛选差异性成分。结果表明:从20批吉祥草HPLC指纹图谱中,选取了13个共有峰,指认其中4个成分,分别为芦丁(峰5)、人参皂苷Rb1(峰11)、薯蓣皂苷(峰12)、薯蓣皂苷元(峰13);20批吉祥草图谱与对照图谱相似度为0.546~0.942;经聚类分析和偏最小二乘判别分析,20批吉祥草均被分成3类,其中S7、S10、S12、S16、S18、S17、S15、S3、S4、S1、S13、S2、S14、S19、S6、S8、S20、S9为第1类,S11为第2类,S5为第3类;经主成分分析,主成分1~4的累积方差贡献率为85.374%,20批吉祥草中S5的综合得分较高,其次是S11;采用变量重要性投影法筛选出7个差异性成分,分别为峰13(薯蓣皂苷元)、峰2、峰7、峰5(芦丁)、峰12(薯蓣皂苷)、峰1和峰6;芦丁、人参皂苷Rb1、薯蓣皂苷、薯蓣皂苷元的质量在一定范围内与其对应的峰面积呈线性关系,检出限(3S/N)为0.005~0.020 mg·g^(-1);对S2进行加标回收试验,4种化学成分的回收率为97.4%~102%,测定值的相对标准偏差(n=6)为1.1%~2.6%;方法用于20批吉祥草分析,芦丁、人参皂苷Rb1、薯蓣皂苷和薯蓣皂苷元的测定值分别为0.249~0.984 mg·g^(-1),0.431~5.851 mg·g^(-1),0.007~0.261 mg·g^(-1)和0.003~0.095 mg·g^(-1)。     

羊肝源穿山龙薯蓣皂苷-α-L-鼠李糖苷酶的分离及其动力学特性

对羊肝中含有的水解穿山龙薯蓣皂苷鼠李糖糖基的穿山龙薯蓣皂苷-α-L-鼠李糖苷酶进行了分离、纯化, 并对其动力学特性进行了研究. 结果表明, 粗酶液经DEAE-Cellulose离子交换层析柱纯化后, 其比活提高了19.9倍. 在pH＝6.8、反应温度为42 ℃、反应时间为8 h和底物浓度为23 mmol/L的条件下, 该酶达到其最高活力. 在10—200 mmol/L范围内, Fe3+和Cu2+对酶活力有明显的抑制作用, Mg2+和Zn2+对酶活力有微弱的激活作用, 而Ca2+对酶有较强的激活作用. 采用SDS-PAGE方法测得酶蛋白分子量为71000. 选择穿山龙薯蓣皂苷、人参皂苷Re和芦丁为酶反应底物, 进行酶的底物专一性研究发现, 穿山龙薯蓣皂苷-α-L-鼠李糖苷酶对其底物具有高度专一性.     

薯蓣皂苷元-葡萄糖C-苷类似物的合成

采用汇集式合成策略,以葡萄糖为原料,经乙酰化、 溴代、消除、硅炔基化、脱除保护基制得(2R,3R) -6-乙炔基-2-(羟甲基) -3,6-二氢-2H-吡喃-3-醇(5);以薯蓣皂苷元为原料,经磺酰化、叠氮化制得叠氮化薯蓣皂苷元8;以5和8为原料,经Click反应合成薯蓣皂苷元-葡萄糖C-苷类似物(9),收率74%,其结构经¹H NMR, ¹³C NMR以及HR-MS(ESI)表征。      

高效液相色谱法测定怀山药中的薯蓣皂苷元

提出了高效液相色谱法测定怀山药中薯蓣皂苷元的含量。样品经无水乙醇提取,用ZORBAX SB-C₁₈色谱柱分离,以甲醇-水（80+20）溶液为流动相淋洗,在波长210 nm处进行测定。薯蓣皂苷元的质量在10～150 ng范围内与其峰面积呈线性关系,检出限（3S/N）为2.5 ng。方法用于分析怀山药样品,回收率在94.2%～104%之间,测定值的相对标准偏差（n=6）为3.1%。     

穿龙薯蓣化学成分的液相色谱-质谱联用分析

穿龙薯蓣(DiosoreanipponicaMakino)为薯蓣科薯芋属植物,产于内蒙古,黑龙江等省区,其根茎俗称穿山龙,既是生产治疗心血管疾病药物地奥心血康的原料药材,又是用于合成多种甾体激素类药物的原料薯蓣皂苷元的重要来源之一。临床报道穿龙薯蓣总皂苷对治疗冠心病、抗动脉粥样硬化、降血脂、平喘、抗炎和抗肿瘤有一定疗效,其有效部位为穿龙薯蓣甾体皂苷.我们采用高效液相与电喷雾串联质谱联用方法分析穿龙薯蓣中主要的皂苷成分,并发现一种未见报道的甾体皂苷元。     

合理利用甾体皂苷元资源的研究 I: 具有油菜甾醇内酯A/B环结构单元的甾体皂苷元的合成

本文提出用薯蓣皂苷元合成油菜甾醇内酯及其类似物的新思想, 从薯蓣皂苷元合成了具有油菜甾醇内酯A/B环结构单元的新甾体皂苷元。作为进一步合成油菜甾醇内酯的重要中间体, 它本身也显示促进植物生长的作用。     

合理利用甾体皂苷元资源的研究 I: 具有油菜甾醇内酯A/B环结构单元的甾体皂苷元的合成

本文提出用薯蓣皂苷元合成油菜甾醇内酯及其类似物的新思想, 从薯蓣皂苷元合成了具有油菜甾醇内酯A/B环结构单元的新甾体皂苷元。作为进一步合成油菜甾醇内酯的重要中间体, 它本身也显示促进植物生长的作用。     

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%.     

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.     

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.     

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.     

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.     

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.     

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.