Phenazine

Structural formula
General
Surname	Phenazine
other names	Dibenzopyrazine
Molecular formula	C 12 H 8 N 2
Brief description	yellow solid
External identifiers / databases
CAS number 92-82-0 EC number 202-193-9 ECHA InfoCard 100.001.995 PubChem 4757 Wikidata Q419781
properties
Molar mass	180.21 g · mol -1
Physical state	firmly
Melting point	172-177 ° C
boiling point	360 ° C
solubility	almost insoluble in water moderately in ethanol , diethyl ether and benzene
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Phenazine is a polycyclic aromatic chemical compound with two nitrogen atoms in the middle of the three rings. This structure is also present in pyrazine as a single ring. Phenazine is a yellow solid and is the starting material for many derived compounds that serve as colorants (e.g. neutral red , safranine , eurhodine , indulin , pyocyanine , mauveine ).

Occurrence

Some phenazine derivatives have an antibiotic effect and are therefore synthesized by many bacteria (e.g. Pseudomonas aeruginosa , Streptomyces , Pantoea agglomerans ) and released into the environment to defend their habitat. The biosynthesis of the two six-membered carbon rings of the phenazines takes place on the shikimic acid route of aromatic biosynthesis via chorismic acid . Almost 100 such naturally occurring compounds have now been identified.

Extraction and presentation

A classic method for the synthesis of phenazine is the reaction of nitrobenzene and aniline in the Wohl-Aue reaction (1901). However, other methods are also known:

• Oxidation of dihydrophenazine , which can be obtained by heating pyrocatechol with o- phenylenediamine .
• Cyclization of o- aminodiphenylamine with hydrochloric acid and iron (III) chloride .

properties

Phenazine occurs in two polymorphic crystal forms. The α – form melts at 174 ° C with a heat of fusion of 23.5 kJ · mol ⁻¹ , the β – form at 175 ° C with a heat of fusion of 23.6 kJ · mol ⁻¹ .

use

Phenazine is the starting material for many dyes (also known as azine dyes) such as neutral red , safranine and mauveine , whereby the ring with the two nitrogen atoms acts as a chromophore. Phenazine dyes generally contain the structure of phenazine as the backbone for this class of dyes. The phenazine ring and phenazine derivatives are important raw materials for the industrial production of pesticides , fragrances and pharmaceuticals . Phenazine is still a complexing agent .

Individual evidence

1. ↑ ^{a b c d e} Phenazine data sheet from AlfaAesar, accessed on March 9, 2010 ( PDF )(JavaScript required) .
2. ↑ Entry on phenazine. In: Römpp Online . Georg Thieme Verlag, accessed on May 30, 2014.
3. ↑ Phenazine data sheet from Sigma-Aldrich , accessed on February 10, 2018 ( PDF ).
4. ↑ ^{a b} Research Report 2006 - Max Planck Institute for Molecular Physiology: The Biosynthesis of Phenazines .
5. ↑ GS Byng, JM Turner: Isolation of Pigmentation Mutants of Pseudomonas phenazinium . In: Journal of General Microbiology . tape 97 , no. 1 , November 1, 1976, p. 57-62 , doi : 10.1099 / 00221287-97-1-57 ( full text [PDF]).
6. ^ Graham S. Byng, John M. Turner: Incorporation of [ ¹⁴ C] shikimate into phenazines and their further metabolism by Pseudomonas phenazinium. In: Biochemical Journal. 164, 1977, p. 139, doi: 10.1042 / bj1640139 .
7. ↑ Structure-based investigations on phenazine biochemistry. ( Memento of August 12, 2010 in the Internet Archive ) .
8. ↑ A. Wohl, W. Aue, On the action of nitrobenzene on aniline in the presence of alkali , in: Chem. Ber. , 1901 , 34 , 2442-2450; doi: 10.1002 / cber.190103402183 .
9. ↑ IJ Pachter and MC Kloetzel: The well-Aue reaction. I. Structure of Benzo [a] phenazine Oxides and Syntheses of 1,6-Dimethoxyphenazine and 1,6-Dichlorophenazine , in: J. Am. Chem. Soc. , 1951 ; 73 (10): 4958-4961; doi: 10.1021 / ja01154a144 .
10. ↑ C. Ris: Ueber das Phenazin , in: Chem. Ber. 1882 , 19 , 2206-2208; doi: 10.1002 / cber.188601902128 .
11. ↑ ML Tomlinson: The preparation of 2: 2'-diaminodiphenylamines and 2: 2'-diacetamidodiphenylamines and their behavior on oxidation , in: J. Chem. Soc. , 1939 , 158-163; doi: 10.1039 / JR9390000158 .
12. ↑ Braga, D .; Grepioni, F .; Maini, L .; Mazzeo, PP; Rubini, K .: Solvent-free preparation of co-crystals of phenazine and acridine with vanillin in Thermochim. Acta 507–508 (2010) 1–8, doi : 10.1016 / j.tca.2010.04.021