Synthese von Dibenzo[a,g]chinolizinen — Ein neuer Zugang zu Protoberberinen
摘要:
A novel synthesis to prepare dibenzo-8-quinolizinones 8 is reported using the intramolecular cyclisation of the benzylated Reissert compounds 6 for the key step. Methylation of 8 by methyllithium gives partial deoxygenated coralynes 10 which in turn can be reduced by NaBH4 yielding the 8-methyltetrahydro-protoberberines 11. The structures are assigned by NMR-spectroscopy.
Compounds with a pyridoisoquinolinone core often appear as members of the protoberberine alkaloid family. Traditional methods to construct this framework normally rely on manipulation of sophisticated reactants. Herein, a palladium-catalyzed reaction of readily available pyridotriazoles and o-bromo/pseudohalo benzaldehydes is described, which provides a modular approach to pyridoisoquinolinone derivatives
Reissert compound studies. XXXIX. A novel approach to the berbine and 6-azaberbine systems and related derivatives of ellipticine
作者:Seshadri Veeraraghavan、Frank D. Popp
DOI:10.1002/jhet.5570180115
日期:1981.1
indoloberbine ring skeletons is reported. Treatment of heterocyclicbases such as isoquinolines, phthalazines, and ellipticine with 2-chloromethylbenzoyl chloride and trimethylsilyl cyanide gave the corresponding Reissert compounds. Treatment of these Reissert compounds with sodium hydride resulted in intramolecular cyclization with loss of hydrogencyanide.
Concise total syntheses of berberine and its analogues enabled by trifluoroacetic anhydride-promoted decarbonylative-elimination reaction
作者:Xifei Yan、Jianfeng Zheng、Wei-Dong Z. Li
DOI:10.1016/j.tetlet.2023.154826
日期:2023.11
The total syntheses of berberine hydrochloride and itsanalogues were achieved by a convergent strategy from available meconine derivatives, which were based on base mediated isoquinoline annulation followed by trifluoroacetic anhydride promoted decarbonylative elimination protocol. Key elements of our approach feature divergent synthesis, step-economy manner, multigram scalable synthesis, transition