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Two new triterpenoid sapon.ins 1 and 2 were isolated from the crude saponin extract of Oxytropis glabra DC by Si gel chromato-grapny . Saponins 1 and 2 were determined to be 3-0-1 β-D-glucopyranosy 1 (1-2)- β -D-glucuronopyranosyl azukisapogenol methyl ester and 3-O-[β-D-glucopyranosyl(1 - 2 ) - β -D-glucuronopyranosyl] azukisapogenol amide, respectively by spectral analysis and chemical methods. 相似文献
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海藻鹧鸪菜化学成分的研究 总被引:7,自引:0,他引:7
海藻鹧鸪菜(CaloglosaLeprieuri,J.Agrardh)种属于红藻松节科,民间广泛用作驱虫药物.有关鹧鸪菜的化学成分报道很少[1,2],已知有甾醇、甘露醇.为了进一步寻找其生理活性物质,我们对采自于中国南海西沙群岛海域样品的化学成分进行... 相似文献
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L. R. Nigmatullina O. B. Flekhter L. A. Baltina N. I. Medvedeva G. A. Tolstikov 《Chemistry of Natural Compounds》2002,38(6):577-578
Reaction of 2-hydroxymethylenebetulonic acid with hydrazine hydrate produced methyl-[3,2-c]-pyrazol-lup- 20(29)-en-28-oate. 相似文献
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酸性离子液体催化脂肪酸甲酯聚合制备二聚酸甲酯 总被引:1,自引:0,他引:1
以 Brönsted-Lewis 酸性离子液体为催化剂, 用于催化生物柴油中不饱和脂肪酸甲酯聚合制备二聚酸甲酯反应, 考察了催化剂种类、催化剂用量、反应温度和时间等因素对聚合反应性能的影响, 得到较佳的反应条件. 结果表明, 当以 1-(3-磺酸)-丙基-3-甲基咪唑氯锌酸盐[HO3S-(CH2)3-mim]Cl-ZnCl2 (ZnCl2 摩尔分数为 0.67) 为催化剂, 生物柴油 15 g, m(生物柴油):m(离子液体) = 15:1, 于 240 oC 下反应 6 h 时, 二聚酸甲酯收率为 63.2%, 其中三聚体含量小于 5%. 另外, 该催化剂重复使用 5 次后, 二聚酸甲酯收率仍超过 63%, 表明其具有较好的重复使用性能. 离子液体的 Brönsted 和 Lewis 酸位的协同效应显著提高了其催化活性. 相似文献
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通过形成二酪氨酸酯酒石酸盐法制备D-酪氨酸的新方法 总被引:1,自引:0,他引:1
研究了在乙醇溶液中光学活性L-酒石酸拆分DL-酪氨酸乙酯时的特性, 发现溶液中同时存在着酒石酸、酪氨酸乙酯酒石酸氢盐和二酪氨酸乙酯酒石酸盐, 三者之间的平衡关系影响拆分结果, 所得酪氨酸的构型与L-酒石酸和DL-酪氨酸乙酯的投料摩尔比有关. 前者的摩尔数大于后者时为富D-酪氨酸乙酯, 小于后者时为富L-酪氨酸乙酯, 两者相当时则得到DL-酪氨酸乙酯. 进一步的研究探讨了D-酒石酸、L-酒石酸与L-酪氨酸乙酯在不同摩尔比下的成盐特性, 从而解释了酒石酸拆分酪氨酸乙酯过程中的这一特性, 说明由于二L-酪氨酸乙酯酒石酸盐和二D-酪氨酸乙酯酒石酸盐在乙醇中溶解度都很小, 因此通过酒石酸拆分酪氨酸乙酯的方法不能得到高光学纯度的D-酪氨酸. 在此基础上, 通过形成二酪氨酸甲酯酒石酸盐的方法, 在甲醇中成功地用D-酒石酸拆分制备了D-酪氨酸, 光学纯度99% ee. 相似文献
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ZHANG Jing-wen ZHANG Xiao-long MA Xiu-li LIU Chang-cheng MU Ying SUN Yun-xiu JIANG Wen-pu HUANG Hua-min LI Yao-xian PENG Wan-ru 《高等学校化学研究》1998,14(1):38-41
StudiesonEsterExchangeReactionZHANGJing-wen,ZHANGXiao-long,MAXiu-li,LIUChang-cheng,MUYing,SUNYun-xiu,JIANGWen-pu,HUANGHua-min... 相似文献
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The chemical constituents of the roots of Zizyphus jujuba Mill. var. spinosa were investigated with a combination of Sephadex LH-20 column, centrifugal partition chromatography and RP-18 low pressure liquid chromatography. We isolated seven flavonoids-quercetin ( 1 ), (+)-dihydroquercetin ( 2 ), (+)-dihydrokaempferol ( 7 ), quercetin-3-0-β-glucoside ( 8 ), 2-hydroxynaringenin ( 11 ), rutin ( 12 ), and quercetin 3-0-(2G-β-D-xylopyranosylrutinoside) ( 13 ); four catechins-(-)-gallocatechin ( 3 ), (-)-epigallocatechin ( 4 ), (-)-catechin ( 5 ), and (-)-epicatechin ( 6 ); and two phenolic carboxylic acids-p-hydroxybenzoic acid ( 9 ) and protocatechuic acid ( 10 ) from the water soluble fraction of the ethanolic extract NMR date of 13 were assigned by 2D NMR techniques. 相似文献
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采用硅胶柱层析-气相色谱法对月桂酸甲酯乙氧基化物(LME)中副产物二酯进行了定量分离与测定,同时考察了不同条件下合成的LME中二酯含量的变化规律。结果表明:LME中二酯含量随环氧乙烷(EO)加合数(n)的增加而先增大后趋平衡,当加合数n为8时,其质量分数为2.13%;并随反应温度升高而增大;随原料甲酯所含碳原子个数增加而降低。 相似文献
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采用超声提取法提取酱腌菜中的对羟基苯甲酸甲酯、对羟基苯甲酸乙酯及对羟基苯甲酸丙酯,在SE30毛细管柱(33 m×0.53 mm,2.65μm)上得到了良好分离。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯及对羟基苯甲酸丙酯在0~750μg/mL浓度范围内与色谱峰面积呈良好的线性关系,相关系数为0.9999。对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯的检出限分别为0.1,0.1,0.2μg/mL,测定结果的相对标准偏差小于3.6%(n=11),平均回收率为84.5%~97.1%。 相似文献
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聚丙烯酸甲酯载体对柱状假丝酵母脂肪酶固定化的研究(Ⅰ) 总被引:4,自引:1,他引:4
合成了一系列不同结构的聚丙烯酸甲酯,考察了它们的固定化酵母脂肪酶催化酯水解反应的效果,得到了载体孔结构对固定化效果影响的一些规律.研究了最佳吸附条件,比较pH和离子强度对酵母脂肪酶自由酶和固定化酶催化酯水解反应活力的影响. 相似文献
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Sofia Zazouli Mohammed Chigr Patrícia A. B. Ramos Daniela Rosa Maria M. Castro Ahmed Jouaiti Maria F. Duarte Snia A. O. Santos Armando J. D. Silvestre 《Molecules (Basel, Switzerland)》2022,27(2)
Zizyphus lotus L. is a perennial shrub particularly used in Algerian folk medicine, but little is known concerning the lipophilic compounds in the most frequently used parts, namely, root bark, pulp, leaves and seeds, which are associated with health benefits. In this vein, the lipophilic fractions of these morphological parts of Z. lotus from Morocco were studied by gas chromatography–mass spectrometry (GC–MS), and their antiproliferative and antimicrobial activities were evaluated. GC–MS analysis allowed the identification and quantification of 99 lipophilic compounds, including fatty acids, long-chain aliphatic alcohols, pentacyclic triterpenic compounds, sterols, monoglycerides, aromatic compounds and other minor components. Lipophilic extracts of pulp, leaves and seeds were revealed to be mainly composed of fatty acids, representing 54.3–88.6% of the total compounds detected. The leaves and seeds were particularly rich in unsaturated fatty acids, namely, (9Z,12Z)-octadeca-9,12-dienoic acid (2431 mg kg−1 of dry weight) and (9Z)-octadec-9-enoic acid (6255 mg kg−1 of dry weight). In contrast, root bark contained a high content of pentacyclic triterpenic compounds, particularly betulinic acid, accounting for 9838 mg kg−1 of dry weight. Root bark extract showed promising antiproliferative activity against a triple-negative breast cancer cell line, MDA-MB-231, with a half-maximal inhibitory concentration (IC50) = 4.23 ± 0.18 µg mL−1 of extract. Leaf extract displayed interesting antimicrobial activity against Escherichia coli, methicillin-sensitive Staphylococcus aureus and Staphylococcus epidermis, presenting minimum inhibitory concentration (MIC) values from 1024 to 2048 µg mL−1 of extract. Our results demonstrate that Zizyphus lotus L. is a source of promising bioactive components, which can be exploited as natural ingredients in pharmaceutical formulations. 相似文献
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我国大戟二萜酯及其生理活性研究新进展 总被引:11,自引:1,他引:11
介绍了我国近10年来从大戟属植物中发现的二萜酯类新化合物及它们的刺激性,抗癌活性和杀菌作用等生理活性的研究,其中包括5种新发现碳骨架的20个高氧化型二萜多酯类化合物。 相似文献