Marine Natural Products for Drug Discovery: First Discovery of Kealiinines A–C and Their Derivatives as Novel Antiviral and Antiphytopathogenic Fungus Agents
摘要:
Leucetta alkaloid kealiinines A-C and kealiinine B derivatives were designed, synthesized, and characterized on the basis of NMR and HR-MS. The anti-TMV and antiphytopathogenic fungus activities of these alkaloids were evaluated for the first time. Kealiinine B exhibited a higher anti-TMV activity than kealiinines A and C. Kealiinine B derivatives 2m (inhibitory rates: 68, 66, and 71% at 500 mu g/mL for inactivation, curative, and protection activity in vivo, respectively) and 2y (inhibitory rates: 69, 64, and 63% at 500 mu g/mL for inactivation, curative, and protection activity in vivo, respectively) showed significantly higher antiviral activity than ningnanmycin (inhibitory rates: 56, 56, and 58% at 500 mu g/mL for inactivation, curative, and protection activity in vivo, respectively), thus emerging as new lead compounds for novel antiviral agent development. Structure activity relationship research provided the basis for structural simplification of these alkaloids. Further fungicidal activity tests revealed that these alkaloids displayed broad-spectrum fungicidal activities. Compounds 2i and 2p displayed good fungicidal activities in vitro against Sclerotinia sclerotiorum and Rhizoctonia cerealis with inhibition rates of 71%/50 mg/kg and 70%/50 mg/kg, respectively.
Hypervalent Iodine(III)-Mediated Cascade Cyclization of Propargylguanidines and Total Syntheses of Kealiinine B and C
作者:Guilong Tian、Pavel Fedoseev、Erik V. Van der Eycken
DOI:10.1002/chem.201700934
日期:2017.4.19
An oxidative cascadecyclization of propargylguanidines promoted by phenyliodonium diacetate (PIDA) was developed. The protocol provides an efficient route for the synthesis of the alkaloids kealiininesB and C as well as homologues. The difference in the electronic nature of the acetylene substituent resulted in two ways of the cyclization. A plausible mechanism is proposed based on the experimental
Synthesis of the Reported Structures for Kealiinines B and C
作者:Joseph B. Gibbons、Keith M. Gligorich、Bryan E. Welm、Ryan E. Looper
DOI:10.1021/ol3019242
日期:2012.9.21
Syntheses of the reported structures of kealiinines B and C have been executed. An intermolecular electrophile-induced cyclization of a pendant arene on an ene-guanidine affords the tetracyclic, oxidized naphthimidazole cores.