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Indazoles
Indazole, also called isoindazole, is a heterocyclic aromatic organic compound. This bicyclic compound consists of the fusion of benzene and pyrazole. Indazole is an amphoteric molecule which can be protonated to an indazolium cation or deprotonated to an indazolate anion. The corresponding ''pKa'' values are 1.04 for the equilibrium between indazolium cation and indazole and 13.86 for the equilibrium between indazole and indazolate anion. Indazole derivatives display a broad variety of biological activities. Indazoles are rare in nature. The alkaloids nigellicine, nigeglanine, and nigellidine are indazoles. Nigellicine was isolated from the widely distributed plant '' Nigella sativa'' L. (black cumin). Nigeglanine was isolated from extracts of '' Nigella glandulifera''. The Davis–Beirut reaction can generate 2''H''-indazoles. Indazole, C7H6N2, was obtained by E. Fischer (''Ann.'' 1883, 221, p. 280) by heating ortho-hydrazine cinnamic acid, : Drugs made from Indazole B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Davis–Beirut Reaction
The Davis–Beirut reaction is ''N,N''-bond forming heterocyclization that creates numerous types of 2''H''-indazoles and indazolones in both acidic and basic conditions The Davis–Beirut reaction is named after Mark Kurth and Makhluf Haddadin's respective universities; University of California, Davis and American University of Beirut, and is appealing because it uses inexpensive starting materials and does not require toxic metals. : Mechanism in base The current proposed mechanism for the Davis–Beirut reaction in base was first published in 2005 by Kurth, Olmstead, and Haddadin. The reaction occurs when a ''N''-substituted 2-nitrobenzylamine is heated in the presence of base, such as NaOH and KOH, and an alcohol and includes the formation of a carbanion The reaction begins with the base removing a hydrogen (1) adjacent to the secondary amine-group, creating a carbanion. The carbanion then extracts an oxygen from the nitro group (2), which is then subsequently protonated, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
