Total Syntheses of Aurachins A and B

Aurachins A and B are alkaloids having 3-hydroxyquinoline N-oxide cores. An efficient method for the synthesis of 3-hydroxyquinoline N-oxides was established and is amenable to the total syntheses of aurachins A and B. Alkylation of 1-(2-nitrophenyl)butan-2-one with farnesyl bromide took place selectively at the benzylic position, and subsequent treatment of the alkylated product with sodium tert-butoxide in dimethyl sulfoxide gave aurachin B. Alkylation of 1-(2-nitrophenyl)butan-2-one with an epoxy iodide derived from farnesol was used to access aurachin A.     

An Enantioselective Total Synthesis of (−)‐Isoschizogamine

A concise enantioselective total synthesis of (?)‐isoschizogamine, a complex bridged polycyclic monoterpene indole alkaloid, was accomplished. N‐Alkylation of an enantio‐enriched imine with an alkyl iodide afforded an iminium salt, which, upon heating by microwave irradiation in the presence of pivalic acid, was converted into the hexacyclic structure of natural product by a complex but ordered domino sequence. The one‐pot process leading to the formation of one C? C bond and three C? N bonds created three rings and three contiguous stereogenic centers with complete control of both the relative and absolute stereochemistry.     

Generating Skeletal Diversity from the C19‐Diterpenoid Alkaloid Deltaline: A Ring‐Distortion Approach

The development of new drugs calls for large collections of diverse molecules with considerable complexity. Ring distortion of natural products provides an efficient and facile approach to access new architectures with intriguing biological activities, by harnessing their inherent complexity. In this study, such a strategy has been explored on an abundant C₁₉‐diterpenoid alkaloid, deltaline, enabling the synthesis of 32 new derivatives bearing a broad spectrum of unique scaffolds. Extensive spectroscopic studies including X‐ray crystallographic analyses strongly supported the structures of the obtained novel skeletons, which present comparable opportunities with the great contributions made by nature for discovery of new lead compounds.     

A biomimetic synthesis of the skeleton of trigonoliimine C

On basis of biomimetic concepts, the skeleton of trigonoliimine C was readily achieved in five steps from N-phthaloyl tryptamine. This result suggested a useful synthetic strategy for trigonoliimine alkaloids with this unique ring system.     

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.     

在线固相萃取结合液相色谱-线性离子阱多级质谱法同时检测生物样品中7种乌头类生物碱

建立了在线固相萃取(on-line SPE)结合液相色谱-线性离子阱多级质谱(LC-LIT/MSⁿ)同时测定全血、尿液和肝组织样品中7种乌头类生物碱的分析方法,并根据7种乌头类生物碱的多级质谱碎片对裂解规律进行了推测和总结。用乙腈沉淀样品中的蛋白质,于稀释和离心后直接进样。经Waters Oasis^® HLB在线SPE柱富集纯化,以0.1%(v/v)甲酸/乙酸铵溶液-0.1%(v/v)甲酸/甲醇溶液为流动相,以Accucore C18为分析柱进行梯度洗脱;在电喷雾电离(ESI)正离子模式下测定;扫描方式为连续反应监测(CRM)。在考察的质量浓度范围内,7种乌头类生物碱的标准曲线符合二阶方程(权重因子1/x),相关系数为0.9991~0.9999;在全血和尿液中的方法检出限为0.02~0.60 ng/mL,在肝组织中的方法检出限为0.02~0.40 ng/g;加标回收率为91.1%~104.7%,日内精密度和日间精密度分别为0.2%~10.7%、1.0%~13.7%(n=6)。该方法简单准确,灵敏度高,能够满足生物样品中7种乌头类生物碱的快速分析。     

酰胺的直接转化:仲酰胺与丹尼谢夫斯基双烯的还原环加成反应

酰胺作为稳定的合成中间体被广泛应用于有机合成和药物化学. 因此, 发展通用、化学选择性的酰胺直接转化的方法十分重要. 在本工作中, 我们报道仲酰胺与丹尼谢夫斯基双烯的还原环加成反应, 用于把仲酰胺直接转化为2-取代-2,3-二氢-4-吡啶酮. 该"一瓶反应"包含酰胺通过三氟甲磺酸酐活化、部分还原、和[4+2]环加成反应3个环节. 基于这一步骤经济型方法, 建立了生物碱(±)-lasubine I和(±)-myrtine的简便、无保护基全合成.     

高效液相色谱法测定麻黄浸膏粉中麻黄类生物碱

采用高效液相色谱法分离了麻黄浸膏粉中去甲基麻黄碱、去甲基伪麻黄碱、麻黄碱、伪麻黄碱和甲基麻黄碱等 5种主要麻黄类生物碱。所用分离柱为HIQSILC18,流动相为含少量 (体积分数为 0 .2 % )甲醇的 0 .0 2mol L磷酸二氢钠溶液 (用HCl和三乙胺调至pH 3.2 )。 5种麻黄类生物碱在 2 5min内得到了有效分离、峰型对称且尖锐。     

Crystal and Molecular Structure of Songorine from the Root of Aconitum szechenyianum Gay

Songorine was isolated from the root of Aconitum szechenyianum Gay and its crystal structure was determined by X-ray single crystal diffraction. The compound compactly packs in an orthorhombic unit cell in the P2₁2₁2₁ space group with unit cell dimensions a = 9.7733(7) Å, b = 13.4892(9) Å, c = 14.8097(10) Å, V = 1952.4(2) Å³ and Z = 4. A series of intricate hydrogen bonds assemble the title compound into a three-dimensional networking structure.