Phenanthridine is a nitrogen heterocyclic compound that is the basis of DNA-binding fluorescent dyes through intercalation. Examples of such dyes are ethidium bromide and propidium iodide. Acridine is an isomer of phenanthridine.

Phenanthridin - Phenanthridine.svg
IUPAC name
3D model (JSmol)
ECHA InfoCard 100.005.396
EC Number
  • 205-934-4
Molar mass 179.217 g/mol
Melting point 107.4 °C (225.3 °F; 380.5 K)
Boiling point 348.9 °C (660.0 °F; 622.0 K)
slightly soluble[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Phenanthridine was discovered by Amé Pictet and H. J. Ankersmit in 1891 by pyrolysis of the condensation product of benzaldehyde and aniline.[2] In the Pictet–Hubert reaction (1899) the compound is formed in a reaction of the 2-aminobiphenyl – formaldehyde adduct (an N-acyl-o-xenylamine) with zinc chloride at elevated temperatures.[3]

The reaction conditions for the Pictet–Hubert reaction were improved by Morgan and Walls in 1931, replacing the metal by phosphorus oxychloride and using nitrobenzene as a reaction solvent.[4] For this reason, the reaction is also called the Morgan–Walls reaction.[5]

Pictet–Hubert reaction

The reaction is similar to the Bischler–Napieralski reaction and the Pictet–Spengler reaction.


  1. ^ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, FL: CRC Press, pp. 3–460, ISBN 0-8493-0594-2
  2. ^ Mittheilung Ueber das Phenanthridin Amé Pictet, H. J. Ankersmit Chemisches Laboratorium der Universität Genf Justus Liebigs Annalen der Chemie Volume 266 Issue 1–2, pp. 138–153 doi:10.1002/jlac.18912660107
  3. ^ Mittheilungen Ueber eine neue Synthese der Phenanthridinbasen Amé Pictet, A. Hubert Berichte der deutschen chemischen Gesellschaft Volume 29 Issue 2, pp. 1182–1189, 1896 doi:10.1002/cber.18960290206
  4. ^ CCCXXXV.—Researches in the phenanthridine series. Part I. A new synthesis of phenanthridine homologues and derivatives Gilbert T. Morgan, Leslie Percy Walls, J. Chem. Soc., 1931, 2447–2456 doi:10.1039/JR9310002447
  5. ^ Jie Jack Li (ed.), 2004, Name Reactions in Heterocyclic Chemistry, Wiley.