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Updated: May 10, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
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Facile Preparation of 4-Substituted Quinazoline Derivatives

Published on: February 15, 2016

1,4-Naphthoquinones in H-bond-directed trienamine-mediated strategies

Łukasz Albrecht1, Clarisa Villegas Gómez, Christian Borch Jacobsen

  • 1Center for Catalysis, Department of Chemistry, Aarhus University , 8000 Aarhus C, Denmark.

Organic Letters
|June 5, 2013
PubMed

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Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
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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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Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.