Protecting-Group-Free Total Synthesis of Isoquinoline Alkaloids by Nickel-Catalyzed Annulation of<i>o</i>-Halobenzaldimine with an Alkyne as the Key Step
作者:Rajendra Prasad Korivi、Chien-Hong Cheng
DOI:10.1002/chem.200902275
日期:2010.1.4
3]dioxol‐5‐yl substitution at the C3 atom and a (CH2)2OH group at the C4 atom. Later, oxidation of the alcohol group in 5 b–d to the aldehyde moiety followed by acid‐catalyzed cyclization and dehydration completes the total syntheses to give oxyavicine, oxynitidine, and oxysanguinarine in 67, 65, and 60 % yields, respectively. The synthesis requires four steps from o‐bromobenzaldehyde derivatives.
描述了一种有效的短总合成苯并[ c ]菲啶生物碱,包括氧鸟嘌呤,氧硝啶和氧桑桂碱。因此,Ñ甲基ö -bromobenzaldimines 1b中- d经历环化区域选择性与4-(苯并[ d ] [1,3]二氧杂环戊烯-5-基)丁-3-炔-1-醇(图2b中) [Ni(cod)2 ]的存在(cod = 1,5-环辛二烯)。原位氧化生成的异喹啉鎓盐可得到异喹啉酮衍生物5 b - d,在C 3原子处有苯并[ d ] [1,3]二氧杂-5-基取代,且(CH 2)2C 4原子上的OH基团。随后,在5 b - d内将醇基氧化为醛部分,然后进行酸催化的环化和脱水,完成了全部合成反应,分别以67%,65%和60%的收率得到了氧鸟嘌呤,氧亚硝胺和氧山桂碱。从邻-溴苯甲醛衍生物的合成需要四个步骤。本文还讨论了这些生物碱向该家族中其他生物碱的转化。
In Vitro Antifungal Activity of Sanguinarine and Chelerythrine Derivatives against Phytopathogenic Fungi
In order to understand the antifungal activity of some derivatives of sanguinarine (S) and chelerythrine (C) and their structure-activity relationships, sixteen derivatives of S and C were prepared and evaluated for in vitro antifungal activity against seven phytopathogenic fungi by the mycelial growth rate method. The results showed that S, C and their 6-alkoxy dihydro derivatives S1–S4, C1–C4 and 6-cyanodihydro derivatives S5, C5 showed significant antifungal activity at 100 µg/mL against all the tested fungi. For most tested fungi, the median effective concentrations of S, S1, C and C1 were in a range of 14–50 µg/mL. The structure-activity relationship showed that the C=N+ moiety was the determinant for the antifungal activity of S and C. S1–S5 and C1–C5 could be considered as the precursors of S and C, respectively. Thus, the present results strongly suggested that S and C or their derivatives S1–S5 and C1–C5 should be considered as good lead compounds or model molecules to develop new anti-phytopathogenic fungal agents.
New methods for the synthesis of naphthyl amines; application to the synthesis of dihydrosanguinarine, sanguinarine, oxysanguinarine and (±)-maclekarpines B and C
作者:Matthew R. Tatton、Iain Simpson、Timothy J. Donohoe
DOI:10.1039/c4cc05209a
日期:——
A new method for preparing naphthyl amines from 1,5 unsaturated dicarbonyl precursors is described; the utility of this new method was proven in the syntheses of several natural products, all containing the benzo[c]phenanthridine core and enabled by a radical promoted cyclisation of the naphthyl amine products formed in the key cyclisation.
Total Synthesis of Oxyfagaronine, Phenolic Benzo[c]phenanthridine and General Synthetic Way of 2,3,7,8- and 2,3,8,9-Tetrasubstituted Benzo[c]phenanthridine Alkaloids
作者:Thanh Nguyen Le、Won-Jea Cho
DOI:10.1248/cpb.54.476
日期:——
Benzo[c]phenanthridine alkaloids such as oxynitidine, oxysanguinarine, oxyavicine and phenolic oxyfagaronine were synthesized from easily available starting benzonitriles 5 and toluamides 6 using a lithiated toluamide-benzonitrile cycloaddition reaction. The coupling reaction provided 3-arylisoquinolinones that were transformed to the benzo[c]phenanthridones. This method is highly efficient and could
A facile synthesis of benzo[c]phenanthridine alkaloids: oxynitidine and oxysanguinarine using lithiated toluamide–benzonitrile cycloaddition
作者:Thanh Nguyen Le、Seong Gyoung Gang、Won-Jea Cho
DOI:10.1016/j.tetlet.2004.02.031
日期:2004.3
Benzo[c]phenanthridinealkaloids oxynitidine and oxysanguinarine were synthesized from easily available starting benzonitrile 5 and toluamide 6 using toluamide–benzonitrile cycloaddition reaction in six steps. This method is so highly efficient that it could be a more useful way for preparing fully aromatized benzo[c]phenanthridine compounds.
使用甲苯酰胺-苄腈环加成反应,通过六个步骤,由易于获得的起始苯甲腈5和甲苯酰胺6合成苯并[ c ]菲啶生物碱氧硝啶和氧山桂碱。该方法是如此高效,以至于它是制备完全芳构化的苯并[ c ]菲啶化合物的更有用的方法。