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2° Amines to N-Nitrosamines: Reaction with NaNO201:20

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.
Nomenclature of Aryl and Heterocyclic Amines01:10

Nomenclature of Aryl and Heterocyclic Amines

The simplest aromatic amine is phenylamine, which contains an –NH2 functionality directly attached to an aromatic ring. The name aniline is designated for this skeleton. As shown in Figure 1, the common names of the functionalized anilines involve prefixes ortho-, meta-, and para- to indicate the substitution position. Different functionalized aniline derivatives also have notable trivial names.
Physical Properties of Amines01:26

Physical Properties of Amines

Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.
Diazonium Group Substitution: –OH and –H01:19

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.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview01:26

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...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism01:37

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.

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A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
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2,4-Dimethyl-6-nitro-aniline.

Hu-Kui Chen1

  • 1Baoji University of Arts and Sciences, Department of Chemistry, Baoji 721013, Shaanxi, People's Republic of China.

Acta Crystallographica. Section E, Structure Reports Online
|May 17, 2012
PubMed
Summary
This summary is machine-generated.

This study reveals that two independent molecules of C(8)H(10)N(2)O(2) in the asymmetric unit are linked by hydrogen bonds. Both molecules exhibit approximate planarity, indicating structural stability.

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Area of Science:

  • Crystallography
  • Molecular Chemistry
  • Structural Analysis

Background:

  • Understanding molecular interactions is crucial in chemistry.
  • Crystal structure determination provides insights into intermolecular forces.

Purpose of the Study:

  • To characterize the crystal structure of C(8)H(10)N(2)O(2).
  • To investigate the intermolecular interactions within the crystal lattice.

Main Methods:

  • Single-crystal X-ray diffraction was employed.
  • Analysis of the asymmetric unit and hydrogen bonding was performed.

Main Results:

  • The asymmetric unit contains two independent, approximately planar molecules.
  • Weak N-H⋯O hydrogen bonds were identified between amino and nitro groups, linking the molecules.

Conclusions:

  • The crystal structure of C(8)H(10)N(2)O(2) is characterized by intermolecular hydrogen bonding.
  • The observed planarity of the molecules suggests specific electronic or steric factors.