芸苔素甾醇类物质的研究进展

芸苔素甾醇类物质（Ｂｒａｓｓｉｎｏｓｔｅｒｏｉｄｓ，简称ＢＲｓ）是广泛存在于植物界的一类新的植物生长物质。ＢＲｓ表现的调节植物生长的生理活性及作用机理与其它的植物激素不同。这类新型的植物生长物质已被广泛应用于农业生产。本文综述了国内外多年来有关ＢＲｓ的生理功能、构效关系及合成等方面的研究进展。     

柱前衍生-高效液相色谱法测定肥料中芸苔素内酯异构体

建立了以苯硼酸为衍生试剂,柱前衍生-高效液相色谱测定肥料中24-表芸苔素内酯(24-EBL)和28-高芸苔素内酯(28-HBR)的方法。样品采用甲醇作为提取溶剂,常温条件下用苯硼酸衍生30 min,乙腈/水(85/15, V/V)为流动相,在222 nm波长下进行分析。结果表明：在0～1250 mg/kg范围内线性关系良好,相关系数(r²)≥0.999。24-EBL和28-HBR的检出限分别为0.46和0.51 mg/kg。样品加标回收率为67.1%～128.5%,批间相对标准偏差为0.09%～2.4%。该方法满足2种芸苔素内酯异构体在肥料内定量分析的要求。     

青蒿素及其一类物结构和合成的研究——Ⅺ.环氧青蒿酸的分离和鉴定

青蒿亦称黄花蒿(Artemisia annua L.),为菊科植物,我国民间用于治疗疟疾。据报道,该植物的主要成分为挥发油、烯炔和倍半萜内酯。倍半萜内酯有青蒿素、青蒿甲素、青蒿乙素及青蒿丙素(脱氧青蒿素)。此外,还有青蒿酸、香豆素及黄酮等。我们由山东七、八月所产青蒿提取物中分到青蒿素、青蒿甲素、青蒿乙素、青蒿丙     

长苞铁杉中两个新的重排羊毛甾烷型三萜

从中国特有植物长苞铁杉树枝的甲醇提物中分离得到2个新的重排羊毛甾烷型三萜,命名为铁杉内酯素A(1)和铁杉内酯素B(2),其结构通过HR-ESIMS,1D和2D NMR等光谱技术确定,铁杉内酯素A(1)的构型进一步通过X单晶衍射确认.     

高效液相色谱-质谱法鉴定总合草苔虫中的草苔虫内酯成分

 采用高效液相色谱分离与质谱检测的联用技术,对总合草苔虫中的草苔虫内酯成分进行定性分析。在以体积比为80∶20的甲醇-水溶液为流动相、采用ODS柱进行分离的色谱条件下,10种草苔虫内酯成分均可获得良好的分离。分析结果表明：深圳大亚湾产地的总合草苔虫中共含有9种已知和1种未知的草苔虫内酯成分。已知成分分别是bryostatin 4,5,6(9),7,8,10,16,17,18,其中bryostatin 7和17是首次从中国海域总合草苔虫中发现的2种痕量草苔虫内酯。该方法简便、准确、灵敏度高,可以很好的对总合草     

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。     

几种芳烃化合物对诸葛菜染色体形态影响的研究

几种芳烃化合物对诸葛菜染色体形态影响的研究肖龙，李峰（四川大学生物工程系成都６１００６４）关键词芳烃化合物，诸葛菜染色体，形态诸葛菜是十字花科芸苔诸葛菜属植物￣［１］，是一种具有极大开发价值的优质油料作物种源￣［２，３，４］。它的染色体形态研究县分类...     

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3.3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。     

新法构建25-羟基油菜甾体的侧链

油菜甾体例如油菜甾醇内酯(1a)和24-表油菜甾醇内酯(2a)是一族新型的甾体植物生长激素(植物生长调节剂).它们具有提高植物生长调节和应变的活性并具有农作物增产效果,已愈益受到国际上的广泛重视[1].     

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.     

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.     

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.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

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.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.