Quinone imines

Structural formula of N -acetyl- p -benzoquinone imine (NAPQI)

Quinone imines are organic compounds which are derived from quinones derived, in which one or both quinoid carbonyl through an imino group is replaced. The compounds with two imino groups are also known as quinonediimines .

N-aryl-substituted quinone imines are dyes ( quinone imine dyes ) from the group of methine dyes .

use

Quinone imines are of particular importance in the development of color films. For example, diaminoarenes can be converted to indoaniline dyes with phenols in the presence of silver ions and metallic silver as a catalyst .

Quinoneimine dyes

General structure of the quinonimine dyes with
X = OH, NH ₂ or NR ₂
Y = O or NH

The quinonimine dyes are aza-analogous diarylmethine dyes . There are three different basic types:

• Indophenols (Y = O, X = OH)
• Indoaniline (Y = O, X = NH ₂ or NR ₂ )
• Indamine (Y = NH, X = NH ₂ or NR ₂ )

Quinoneimine dyes are obtained from the reaction of phenol or aniline (as nucleophile ) with an electrophilic nitroso aromatic and subsequent dehydration . The simplest approach is the acidic oxidation of the corresponding diphenylamine derivatives.

Indophenols

• Tillman's blue

Indoaniline

• Phenol blue
• Naphthol blue
• Rosindole

Indamine

• Bindschedler's green
• Phenazine
  • Safranine
  • Indulin
  • Nigrosine
• Phenothiazines (thiazine dyes)
  

  Phenothiazines, general structure
  • Hydron blue R
  • Methylene blue
  • Thionine
• Phenoxazine
  • Gallocyanin
  • Meldola blue
  • Nile blue
  • Nile red

Individual evidence

1. ↑ Quinone imine. Royal Society of Chemistry, accessed July 22, 2019 . 
2. ↑ Ulfrich Nickel: Reactions with Wurster's cations . In: Chemistry in Our Time . tape 12 , no. 3 , 1978, p. 89-98 , doi : 10.1002 / ciuz.19780120305 .
3. ↑ ^{a b} Houben-Weyl Methods of Organic Chemistry Vol. VII / 3b, 4th Edition o-Quinones, Dipheno- and Stilbenequinones, Higher Ring Ketones, Quinoles, Quinone Derivatives . Georg Thieme Verlag, 2014, ISBN 3-13-180494-7 , p. 121, 236 ( limited preview in Google Book search).
4. ↑ ^{a b} Entry on quinone imines. In: Römpp Online . Georg Thieme Verlag, accessed on September 15, 2018.
5. ↑ ^{a b} Hans R. Schweizer: Artificial organic dyes and their intermediate products . Springer-Verlag, 2013, ISBN 978-3-642-87245-7 , pp. 294 ( limited preview in Google Book search).