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1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO₂ Overview

Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
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...

2° Amines to N-Nitrosamines: Reaction with NaNO2

2° Amines to N-Nitrosamines: Reaction with NaNO₂

Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO₂ Mechanism

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.

Nitrosation of Enols

Nitrosation of Enols

The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.

Diazonium Group Substitution: –OH and –H

Diazonium Group Substitution: –OH and –H

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.

ortho–para-Directing Activators: –CH3, –OH, –&NoBreak;NH2, –OCH3

ortho–para-Directing Activators: –CH₃, –OH, –⁠NH₂, –OCH₃

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...

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Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

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Published on: January 19, 2016

4-Meth-oxy-anilinium nitrate.

Hajer Rahmouni, Wajda Smirani Sta, S Salem Al-Deyab

Acta Crystallographica. Section E, Structure Reports Online

|November 9, 2011

Summary

This study details the crystal structure of a p-ansidinium nitrate compound. Molecular interactions, including hydrogen bonds, form a complex three-dimensional network within the crystal lattice.

Area of Science:

Crystallography
Materials Science
Chemical Physics

Background:

Understanding molecular interactions is crucial for materials design.
Crystal packing influences material properties.
Aniline derivatives are widely studied for their chemical properties.

Purpose of the Study:

To elucidate the crystal structure of the title compound, C(7)H(10)NO(+)·NO(3) (-).
To investigate the intermolecular forces governing crystal packing.
To characterize the three-dimensional network formed by molecular interactions.

Main Methods:

Single-crystal X-ray diffraction analysis.
Crystallographic data collection and refinement.
Analysis of intermolecular forces (Coulombic, van der Waals, hydrogen bonding).

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One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates

One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates

Published on: January 15, 2018

Main Results:

The asymmetric unit contains two p-ansidinium cations and two nitrate anions.
Multiple bifurcated N-H⋯O hydrogen bonds were identified.
These interactions consolidate the crystal packing into a 3D network.

Conclusions:

The crystal structure is stabilized by a combination of electrostatic, van der Waals, and extensive hydrogen bonding.
The observed 3D network highlights the importance of hydrogen bonds in crystal engineering.
This detailed structural information provides a basis for understanding the solid-state behavior of p-ansidinium nitrate.