甘草次酸衍生物的合成

豆科植物甘草中含有大量甘草次酸(Glycyrrhetinic Acid)。近代药理实验表明,甘草的抗炎症、抗溃疡以及抗变态反应等功效,主要归因于甘草中所含的甘草甜素,甘草次酸及其衍生物。多年来,国内外学者对甘草次酸     

甘草次酸衍生物的合成及其抗癌活性

设计合成了6种甘草次酸衍生物,用元素分析、波谱分析鉴定了它们的结构,并比较了它们的体内、体外抗癌活性,均表现出较好的活性,尤其是化合物Ⅰa,Ⅰb口服效果比盐酸氮芥还好,表现出甘草次酸对氮芥有明显的增效应用。     

11—脱氧甘草次酸衍生物的合成

用甘草次酸（Ａ）和甘草次酸甲酯（Ｂ）还原制得１１－脱氧甘草次酸（１）和１１－脱氧甘草次酸甲酯（２）。以此为原料进行酰化，合成了十种３－位酯化衍生物，再与碱金属氧化物反应合成了７种盐类衍生物。用ＩＲ，ＨＮＭＲ，ＭＳ和元素分析确证了它们的结构。     

甘草次酸衍生物的合成

以甘草次酸为原料,合成了4个甘草次酸衍生物.其结构经<'1>H NMR,IR和MS确证.     

11－脱氧甘草次酸衍生物的合成

用甘草次酸（Ａ）和甘草次酸甲酯（Ｂ）还原制得１１－脱氧甘草次酸（１）和１１－脱氧甘草次酸甲酯（２）。以此为原料进行酰化，合成了十种３－位酯化衍生物，再与碱金属氧化物反应合成了７种盐类衍生物。用ＩＲ、￣１ＨＮＭＲ、ＭＳ和元素分析确证了它们的结构。     

甘草次酸及其衍生物的质谱研究

本文通过应用ＥＩ质谱和高分辨质谱对甘草次酸及其衍生物进行研究，阐明了分子离子的各种裂解、重排机理，讨论了主要离子的形成过程以及不同取代基对分子离子峰强度的影响。并用软电离手段──快原子轰击正、负离子（ＰＦＡＢ和ＮＦＡＢ）质谱，使ＥＩ谱上不出现分子离子峰的两个化合物而获得满意结果。     

新型甘草次酸酰胺杂环衍生物的合成及其抗结核活性

以18β-甘草次酸为原料,经过多步酰胺化反应合成了14个含不同杂环的新型甘草次酸多酰胺衍生物(11a～11n),收率78.6%～92.3%,其结构经1H NMR,13C NMR和IR表征。其中11i和11n的初步抑菌活性测试结果表明,杂环酰胺基团对甘草次酸衍生物的抗结核活性具有明显的增效作用。     

11-脱氧甘草次酸衍生物的合成

本文报道了具有潜在药理活性和应用前景的11-脱氧甘草次酸酯、11-脱氧甘草次酸盐的合成方法。     

新型甘草次酸异噁唑衍生物的合成

以甘草次酸(脱氧甘草次酸)和3-取代苯基-5-氨甲基-异噁唑为原料, 合成了4种甘草次酸异噁唑衍生物, 通过IR, 1H NMR, 13C NMR及FABMS等方法确定了化合物的结构. 同时用L9(34) 正交试验对酰胺化反应的条件进行优化, 确定了酰化反应的最佳条件.     

18β-甘草次酸A环开环衍生物的合成及抗肿瘤活性

采用化学方法在18β-甘草次酸A环上进行结构修饰,合成了一系列新颖的A环具有不同官能团的开环衍生物.初步研究了它们对人体肝癌细胞HepG-2的体外细胞毒活性,结果表明,羟基的数目和位置对抑制HepG-2细胞增殖起着重要的作用.     

Synthesis and Anti-tumor Activity of Novel Glycyrrhetinic Acid Derivatives

Twenty-five derivatives of glycyrrhetinic acid(GA)modified on the A-ring,at C30 and C11 positions were synthesized.Their in vitro cytotoxicity against various cancer cell lines[henrietta lacks strain o...     

Synthesis of 3-Fluoro-Oxetane δ-Amino Acids

Starting from d-xylose, 2,4-anhydro-5-N-(tert-butoxycarbonyl)amino-5-deoxy-3-fluoro-d-arabinonic acid 11 was synthesized over 10 steps including ring contraction, fluorination, and ester hydrolysis. Bromine oxidation of d-xylose followed by benzylidenation in a one-pot procedure led to a ca. 1:1 mixture of lactone 3 and 2,4;3,5-dibenzylidene xylonic acid (4) as by-product. For the synthesis of the d-xylo derivative 24, the chosen starting material was 1,2-O-isopropylidene-α-d-xylofuranose. A total of 14 steps including epimerization, ring contraction, fluorination, and saponification led to the desired fluoro-oxetane δ-amino acid 24. Hydrolysis of the 3-fluoro-oxetane δ-amino esters 10 and 23 by means of LiOH was successful in agreement with the results previously reported for similar 3-methoxy oxetanes, whereas chemical hydrolysis was not possible for 3-hydroxy derivatives.     

Synthesis of β-Amino Acid Derivatives

In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area.     

Divergent Synthesis of γ-Amino Acid and γ-Lactam Derivatives from meso-Glutaric Anhydrides

The first divergent synthesis of both γ-amino acid and γ-lactam derivatives from meso-glutaric anhydrides is described. The organocatalytic desymmetrisation with TMSN₃ relies on controlled generation of a nucleophilic ammonium azide species mediated by a polystyrene-bound base to promote efficient silylazidation. After Curtius rearrangement of the acyl azide intermediate to access the corresponding isocyanate, hydrolysis/alcoholysis provided uniformly high yields of γ-amino acids and their N-protected counterparts. The same intermediates were shown to undergo an unprecedented decarboxylation–cyclisation cascade in situ to provide synthetically useful yields of γ-lactam derivatives without using any further activating agents. Mechanistic insights invoke the intermediacy of an unconventional γ-N-carboxyanhydride (γ-NCA) in the latter process. Among the examples prepared using this transformation are 8 APIs/molecules of considerable medicinal interest.     

Stereoselective Synthesis of 1-Aminocyclopropanecarboxylic Acid Derivatives via Ylide Cyclopropanation of Dehydroamino Acid Derivatives

1‐Aminocyclopropanecarboxylic acid derivatives are synthesized from readily available dehydroamino acid derivatives via sulfur ylide. A range of different ylides are employed and the corresponding aminocyclopropanes are afforded with reasonable diastereoselection in good yields.     

Synthesis of Betulonic Acid Derivatives Containing Amino-Acid Fragments

New derivatives of betulonic acid containing on C-28 fragments of amino acids or their methyl esters were prepared as potential biologically active agents.