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Facile Preparation of 4-Substituted Quinazoline Derivatives
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Published on: February 15, 2016

2-Nitrosoamino-3-methylimidazo[4,5-f]quinoline stability and reactivity

Vijaya M Lakshmi1, Fong Fu Hsu, Terry V Zenser

  • 1Division of Geriatric Medicine, VA Medical Center, Missouri 63125, USA.

Chemical Research in Toxicology
|May 18, 2004
PubMed

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The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
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In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
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All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...