利用薯蓣皂甙元完整骨架合成偏诺皂甙元

报道了从薯蓣皂甙元合成偏诺皂甙元, 偏诺皂甙元是中药重楼的生物活性成分的甙元. 合成方法展现了利用资源性化合物的一个新策略, 即充分合理地利用起始原料的完整骨架和全部官能团的思想在转化薯蓣皂甙元成偏诺皂甙元的过程中得以实现. 合成的关键步骤是区域选择性转化胆甾-5-烯-16,22-二酮-3,26-二醇成为胆甾-5,16-二烯-22-酮-3,26-二醇. 此关键反应步骤也可用于cephalostatin 和 OSW-1的合成.     

利用薯蓣皂甙元完整骨架合成澳洲茄胺

澳洲茄胺1是中药龙葵生物活性成分澳洲茄碱和澳洲茄边碱的甙元, 具有抗肿瘤等生物活性. 利用薯蓣皂甙元的完整骨架, 以16-羟基甾体皂甙元的溴代开环反应为关键反应, 经9步反应, 以21%的总收率完成了澳洲茄胺1的合成.     

诺蒎酸的超声合成

以β-蒎烯为原料,通过KMnO4氧化辅以超声辐照手段,进行了诺蒎酸的合成条件优化研究.正交实验表明,声强对诺蒎酸的产率影响最大,其次为pH、原料配比、反应温度和时间;单因素实验表明,诺蒎酸的产率随着声强的增大而增大.在声强0.38W/CM2、pH=10、n(β-蒎烯)/n(KMnO4)=1/2、15℃反应30min的优...     

偏高岭土合成4A沸石机理的研究

用XRD、FT IR、ICP、SEM、化学分析等方法研究了偏高岭土合成4A沸石的晶化反应机理。偏高岭土在NaOH溶液中部分溶解 ,且结构迅速转变为偏高岭土 * ,并伴有硅铝酸钠凝胶形成。偏高岭土 *也不断在碱液的作用下凝胶化 ,生成的凝胶进一步再转变为4A沸石 ,这两个过程在大部分反应时间里是同时进行的 ,直到晶化结束。液相参与凝胶、4A沸石前驱及晶核等的形成和4A沸石的成长。偏高岭土 *的凝胶化速度是整个晶化过程的决定步骤 ,该晶化过程极易形成大量聚晶。     

一种含N-乙酰氨基葡萄糖三糖熊果酸皂苷的合成

本文采用汇聚式糖苷化策略以48.0%的总产率合成了一种含N-乙酰氨基葡萄糖三糖熊果酸皂苷ursolic acid 3-yl -L-arabinopyranosyl-(1→2)-α-L- arabinopyranosyl-(1→6)-2-acetamido-2-deoxy-β-D-glucopyranoside 1，其结构通过¹H NMR，¹³CNMR，二维核磁谱和质谱得到了确证。     

三种天然脱氧核苷的高效合成

本文以1-氯-2-脱氧-α-3,5-二-O-(对氯苯甲酰基)呋喃核糖(1)(以下简称氯代糖)为原料, 开发出可以适用于大规模工业生产的简单、 高效的合成上述三种天然核苷路线.     

2H-苯骈吡喃类化合物的简便合成方法

2 H-苯骈吡喃(2 H-1-benzopyranes,1)又称色烯(chrom-3-ene),是一类天然有机化合物的基本骨架。许多包烯类化合物具有生物活性和光致变色效应,因此它们的合成方法一直是合成化学家感兴趣的课题。本文报道一种简便合成2 H-苯骈吡喃基本骨架的新方法,并用此法合成了从 Ageratum 属植物中分离得到的2,2-二甲基-6,7-二甲氧基苯骈吡喃(2)。     

TEBA催化合成非诺贝特酸

在50%氢氧化钾溶液中,4-羟基-4'-氯二苯甲酮(1),氯仿和丙酮在相转移催化剂TEBA的催化下发生缩合反应合成了非诺贝特酸.最佳反应条件为:1 30 g,丙酮120 g,TEBA 2.5 g,氯仿40 g,于30 ℃滴加氯仿,产率89.7%.     

Synthesis of the aglycon of aspafiliosides E and F via a spiroketal-forming cascade

A facile synthesis of C17α-OH-tigogenin, the aglycon of aspafiliosides E and F, is described. The crucial step is the spiroketal-forming cascade, which forms the rings EF in one step and provides a new strategy for spiroketal ring closure in steroidal sapogenins and other substrates. This synthesis minimizes redundant oxidation-reduction manipulations of previous syntheses.     

两种天然齐墩果酸皂苷的合成

3-O-[β-D-Glucopyranosyl-（1→3）-α-L-arabinopyranosyl]-oleanolic acid-28-O-[β-D-glucopyranosyl] ester 1 was synthesized concisely by a convergent strategy. Using stepwise fashion for the synthesis of saponin 2, 3-O-{[β-D-glucopyranosyl-（1→2）]-[α-L-arabinopyranosyl-（1→3）]-α-L-arabinopyranosyl）-oleanolic acid-28-O-（β- D-glucopyranosyl） ester, an abnormal phenomenon, that the terminal arabinosyl residue took the ^1C4 conformation instead of typical ^4C1 form, was observed. Deprotection or heating could not resume the normal conformation, which resulted in the product of 2＇ not 2.     

Facile Synthesis of Several Oleanane-Type Triterpenoid Saponins

Facile synthesis of the natural oleanane-type triterpenoid saponin 1 isolated from Panax japonicus C. A. Meyer var major (Burk.) C. Y. Wu et K. M. Feng and its derivatives is reported. The glucuronide residue in saponins at a later stage via TEMPO-mediated oxidation of the primary-OH has been achieved. All structures of new compounds were established by means of ¹H NMR, ¹³C NMR, HRMS, and optical rotation.     

Structure,Bioactivity and Analytical Methods for the Determination of Yucca Saponins

Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described. Out of these, the bioactivity of 68 saponins derived from the isolation of Yucca or other genera has been evaluated. Regarding the evaluation and quality control of the saponins from this genus LC-MS technique is the most often used. Nevertheless, the development of methods for their routine analysis in commercial preparations are needed. Moreover, most of the studies found in the literature have been carried out on Y. schidigera extract, since is the most often used for commercial purposes. Only eight of the 50 species that belong to this genus have been studied, which clearly indicates that the identification of saponins present in Yucca genus is still an unresolved question.     

Screening for Astragalus hamosus Triterpenoid Saponins Using HPTLC Methods: Prior Identification of Azukisaponin Isomers

Due to their particular structural characteristics, the extraction and isolation of saponins from plants present a serious challenge. In this study, specific extraction protocols were first implemented to extract the secondary metabolites from Astragalus hamosus and, more precisely, the saponins. Subsequent purification of the extracts was based on a single chromatographic technique, high-performance thin-layer chromatography, applying two development systems: a one-step system that separated molecules according to their polarity and a multiple development system that made it possible to detect the triterpenoid saponins, azukisaponin or soyasapogenol at a retarded Rf of 0.2. The difficulties of detecting the Astragalus hamosus saponins encountered during the extraction and purification of the extracts have been highlighted and the strategy carried out to isolate the saponins has been discussed.     

达玛烷皂苷Ginsenoside Re与Notoginsenoside R1的全合成

采用汇聚式合成的方式,充分利用原人参三醇各羟基活性的差异,采用高效的区域选择性保护策略,并以Au（I）催化的糖苷化反应对达玛烷20位大位阻酸敏感羟基和6位羟基及6-O-Glc'糖基2位羟基连续三次糖苷化,以最长线性13步分别以5.1%和4.5%的收率合成了天然双糖基达玛烷皂苷Ginsenoside Re（1）和Notoginsenoside R₁（2）.     

拓扑替康中三个有关物质的合成

采用易得的原料、简单的化学方法和方便的操作,设计了新的合成路线,制备了拓扑替康药物报批中的三种相关杂质。分别由拓扑替康盐酸盐(1)经游离、酯水解开环反应制备得到了拓扑替康羧酸钠盐(2),由拓扑替康(11)经正丙醇取代反应制备得到9-丙氧甲基-10-羟基喜树碱(4),以及由10-羟基喜树碱(5)经羟甲基化反应制备得到9-羟甲基-10-羟基喜树碱(3)。     

Two New Steroidal Saponins from the Fresh Leaves of Agave sisalana

A new furostanol saponin, sisalasaponin C ( 1 ), and a new spirostanol saponin, sisalasaponin D ( 2 ), were isolated from the fresh leaves of Agave sisalana, along with three other known steroidal saponins and two stilbenes. Their structures were identified as (3β,5α,6α,22α,25R)‐3,26‐bis[(β‐D ‐glucopyrano‐ syl)oxy]‐22‐hydroxyfurostan‐6‐yl β‐D ‐glucopyranoside ( 1 ), (3β,5α,25R)‐12‐oxospirostan‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→3)‐[β‐D ‐xylopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranoside ( 2 ), (3β,5α,6α,22α,25R)‐22‐methoxyfurostane‐3,6,26‐triyl tris‐β‐D ‐glucopyranoside, cantalasaponin‐1, polianthoside D, (E)‐ and (Z)‐2,3,4′,5‐tetrahydroxystilbene 2‐O‐β‐D ‐glucopyranosides. The last three known compounds were isolated from the fresh leaves of Agavaceae for the first time. The structures of the new compounds were elucidated by detailed spectroscopic analysis, including 1D‐ and 2D‐NMR experiments, and chemical techniques.