In vitro germination and shoot proliferation of the threatened species Cinchona officinalis L(Rubiaceae).

Cinchona officinalis （Rubiaceae） is an endemic species of the Loja Valley in southern Ecuador with medicinal uses. Because of over-exploitation in the nine- teenth century and more recent disturbances to its ecosystem, C. officinalis populations are threatened. Currently, natural regeneration of the populations is low, despite its high plant regeneration and seed formation capacity. In the present study, an efficient protocol for germination, shoot proliferation and plantlets regeneration was developed for this species. Phenolic content and germination rate of C. officinalis seeds were compared with a control species, C. pubescens. Nodal segments from seedlings of C. officinalis were cultured on Gamborg medium supplemented with different combinations of plant growth regulators. Because the phenol content is high in C. officinalis, the phenolic should be removed with hydrogen peroxide or water washes to stimulate germination. Shoots and callus developed from nodal segments within 45 days using most of the tested combinations of plant growth regulators. The best rates of shoot proliferation, callus formation and adventitious buds were obtained in medium supplemented with 5.0 mg L^-1 6-benzyl-aminopurine and 3.0 mg L^-1 indole- 3-butyfic acid.

Asymmetric Hydrogenation Synthesis of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic Acid by Cinchona Modified Pd(0)-α-FeOOH Catalyst

Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-a-FeOOH was reported and ee抯 of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic acid ((S)-(+)-naproxen) up to 98% was achieved firstly.

A convenient microwave-assisted synthesis of cinchona alkaloid-derived ligands

辛可宁的有效合成导出碱的 ligands 基于没有溶剂的帮助微波的反应被描述。与奎宁，金鸡纳中毒或 cinchonidine 联合 1,4-dichlorophthalazine 或 3,6-dichloropyridazine 提供二度辛可宁或单音辛可宁的导出碱的 ligands 在对在在最佳微波条件下面的 15 min 以内的好收益(5289%) 中等。

Computational studies of cinchona alkaloid-catalyzed asymmetric Michael additions

Cinchona alkaloid is one of the most effective organocatalysts that facilitate a wide range of transformations. To elucidate the mechanistic details and especially the origins of the observed high enantio- and diastereoselectivities, computational chemists have contributed dramatic efforts in this important area. This review covers the recent computational studies on the cinchona alkaloid-catalyzed asymmetric Michael additions, including both C-C and C-S bond formations, to present a general viewpoint of these fruitful advances. Based on the types of bond formation and the cinchona alkaloid catalysts, key information regarding the activation model and the origins of enantioselectivities is discussed.

Using Natural Cinchona Alkaloids to Promote the Enantioselective Addition of Dialkylzinc to N-Diphenylphosphinylimines

Cinchona alkaloids are utilized as chiral ligands to promote the enantioselective addition of dialkylzinc to N-diphenylphos-phinylimines affording enantiomerically enriched N-diphenyl-phosphinylamines in up to 91% ee.

Cinchona Alkaloid-catalyzed Asymmetric Direct Mannich Reaction of Malononitrile to Imine for Synthesis of β-Amino Malononitrile

The first direct asymmetric Mannich reaction of malononitrile to N-Boc-protected imines has been developed with cinchona alkaloid as catalyst. The procedure could tolerate a relatively wide range of substrates, and results in excellent yields and good enantioselectivities even in the presence of only 1 mol% of catalyst loading. The present work provides an easy access to β-amino malononitrile derivatives.

A Cu/Cinchona P,N-ligand system enabled general asymmetric C(sp^3)–C(sp) coupling

Due to the special structural feature and versatile reactivity towards various types of transformations,alkynes have inspired continuous research interest for their generation,incorporation and application in organic synthesis,chemical biology and material science[1].Notably,since its invention in 1975,the Sonogashira reaction,which efficiently couples aryl halides with aryl or vinyl terminal alkynes via Pd(0)/Cu(I)synergistic catalysis.

An easy route to exotic 9-epimers of 9-amino-(9-deoxy) cinchona alkaloids with(8S,9R) and(8R,9S)-configurations through two inversions of configuration

Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.

A green access to supported cinchona alkaloid amide catalysts for heterogeneous enantioselective allylsilylation of aldehydes and process intensity evaluation in batch and flow

We report herein a new class of polystyrene-supported cinchona alkaloid amide catalysts for enantioselective allylation of various aldehydes using allyltrichlorosilane under both batch and continuous flow conditions.The supported catalyst was synthesized using an environmentally benign coupling agent with a surfactant in aqueous media.Under batch conditions,consistently high yields and enantioselectivity were obtained for the allylation of aliphatic aldehydes with recycling and reuse of the catalyst for more than 10 runs.Subsequently,this catalytic system was successfully implemented into a packed bed flow reactor with similar efficiency and enantiose-lectivity.While flow is a viable option,the batch methodology has better potential for application at a larger-scale setting upon the comparison of space-time yield and catalyst loadings.With the sustainable synthesis and great recyclability of our polymeric catalyst,this methodology holds great potential for the large-scale delivery of valuable enantiopure homoallylic alcohols.

Enantioselective direct aldol-type reaction of 4-hydroxycoumarin with ethyl trifluoropyruvate catalyzed by modified cinchona alkaloids

A new enantioselective aldol-type reaction of 4-hydroxycoumarins and ethyl trifluoropyruvate has been developed. In the presence of (DHQD)2PHAL (5 mol%), ethyl trifluoropyruvate could react with various 4-hydroxycoumarins to afford novel 4-hydroxycoumarin derivatives containing a tertiary trifluoromethyl alcohol center in good yields with moderate enantioselectivities.

Chiral Cinchona Alkaloid-Thiourea Catalyzed Mannich Reaction for Enantioselective Synthesis of β-Amino Ketones Bearing Benzothiazol Moiety

有 acetylacetone 的 imine 的 Mannich 反应被修改 chiral 辛可宁有效地催化导出碱的 thiourea。反应导致了氨基的羰基在高收益和好 enantioselectivities 加重的 chiral。学习第一次证明有从 benzothiazole 导出的杂环的 imine 的未修改的 acetylacetone 的 Mannich 反应能被 chiral bifunctional organocatalyst 支持。

绿色化学理念下奎宁苯甲酰酯金鸡纳生物碱衍生物的微波无溶剂合成的有机化学自主设计性教学实验

目的探讨绿色化学理念下开设有机化学自主设计性教学实验的意义。方法基于绿色化学理念,设计奎宁苯甲酰酯类金鸡纳生物碱衍生物的微波无溶剂合成,完成自主设计性教学实验。结果实验内容新颖,涵盖酯类微波无溶剂合成方法、产物后处理、柱层析纯化等操作步骤,与医药学专业的有机化学理论知识契合度高,同时,实验中利用核磁共振氢谱、高分辨质谱等波谱学数据对产物结构进行了表征,对于培养学生将理论课中所学知识点灵活用于实践解决问题的能力起到了积极促进作用,且使学生建立起绿色合成化学的理念。结论该实验不仅能有效提升学生学习的自主性,激发学习兴趣,强化其实验基本操作技能,也使学生对科学研究工作的思路有更好地认识,为其后续其他专业课程的学习打牢基础。

铜催化不对称合成螺环吡唑啉酮的反应因素评价研究

利用炔系硝基烯烃和吡唑酮的迈克尔加成/Conia-ene环化反应立体选择性合成手性螺环吡唑啉酮,并对影响反应的因素进行考察,比较了过渡金属、不同骨架的配体、溶剂、温度对反应的影响.结果表明,当以金鸡纳碱和廉价金属铜为催化剂,三氯甲烷为溶剂在-40℃下,反应可以达到97%的产率、大于20:1的dr值和91%的ee值.

辛可宁-方酰胺催化剂的合成及应用

以9-氨基-(9-脱氧)表辛可宁(2)和方酸二乙酯(3)为原料,经缩合反应得到一种结构新颖的辛可宁-方酰胺催化剂(1),并将其应用于催化β-硝基苯乙烯(4)和乙酰丙酮(5)的不对称Michael加成反应,得到手性3-(2-硝基-1-苯基乙基)戊-2,4-二酮(6),通过1HNMR、^(13)CNMR、MS等手段对辛可宁-方酰胺催化剂及催化产物6的结构进行了表征,并对催化产物6的合成条件进行了优化。结果表明,在辛可宁-方酰胺催化剂用量n(辛可宁-方酰胺催化剂)∶n(β-硝基苯乙烯)为0.08∶1、溶剂为二氯甲烷、室温下反应12 h的最佳条件下,催化产物6收率达到90%,ee值>99%。

金鸡纳在中国的认知、引种与治疟使用演变

1693年金鸡纳因其突出的治疟效力传入中国,初现于宫廷但中国官方文献记载寥寥,18世纪中叶后私人著作与报刊中记录颇多,金鸡纳及其相关知识有了较大的社会接受面。金鸡纳在中国的引种时间始于1874年,最早成功种植的记录在1876年,比此前学界所认为的年份提早许多。19世纪上半叶,由于化学技术进步与国际市场影响,生药金鸡纳逐渐被化合药奎宁取代。奎宁治疟在中国最早由海关外籍医生引入使用,并很快被中国西医接受,且具备了在临床上注重服药时间并使用他药配合的经验;20世纪以后,奎宁被纳入中医药体系,很快实现早期的中西医结合治疟。以金鸡纳为例,探索近代中国对外来药物的接受过程,有助于研究当下全球传染病流行中新理念、新药物的推广。

生境之困:清末民初中国传统医者的金鸡纳论争

自西学东渐开始,西医西药便不断输入中国,随之传入的金鸡纳也渐渐成为民众的日常医疗用药,引起赵学敏、裘吉生、包识生、刘丙生等中国传统医者的关注。他们对金鸡纳的认知逐步从“谜药”转变为“妙药”,并于近代本土化的过程中,以《神州医药学报》为主要阵地掀起了一场关于金鸡纳药性的论争。这场论争虽扑朔迷离,但基于金鸡纳呈现的研究路径和观点却清晰地展现出近代中国传统医学、医者所面临的“焦虑”与“生境”以及面对冲击时医者的努力与抗争。

超声法提取金鸡纳生物碱的工艺

研究金鸡纳总生物碱的超声提取工艺.采用L9(34)正交设计通过正交试验得出了超声提取的最佳工艺条件.超声提取的影响因素顺序为提取次数>提取时间>料液比,其最佳提取条件为A2B2C2,即8倍量的甲苯提取液提取4次,每次45 min.实验证明该提取工艺方法经济合理.

高分子支载的金鸡纳生物碱催化剂在不对称催化反应中的应用进展

综述了近年来高分子支载的金鸡纳生物碱催化剂在不对称双羟基化反应、不对称Michael加成反应、活性亚胺的不对称烷基化反应以及潜手性酮的不对称还原反应中的应用及最新进展。