Pyridazine

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Pyridazine
Skeletal formula with numbering convention
Pyridazine molecule
Pyridazine molecule
Names
IUPAC name
Pyridazine
Other names
1,2-diazine, orthodiazine, oizine
Identifiers
289-80-5 YesY
ChEBI CHEBI:30954 YesY
ChEMBL ChEMBL15719 YesY
ChemSpider 8902 YesY
Jmol-3D images Image
PubChem 9259
RTECS number GY2390000
Properties
C4H4N2
Molar mass 80.09 g/mol
Appearance colorless liquid
Density 1.107 g/cm3
Melting point −8 °C (18 °F; 265 K)
Boiling point 208 °C (406 °F; 481 K)
Related compounds
Related compounds
pyridine, pyrimidine, pyrazine
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

Pyridazine is a heterocyclic organic compound with the molecular formula (CH)4N2. It contains a six-membered ring with two adjacent nitrogen atoms, and is aromatic.[1] It is a colorless liquid with a boiling point of 208 °C. It is isomeric with two other (CH)4N2 rings, pyrimidine and pyrazine.

Occurrence[edit]

Pyridazines are rare in nature, possibly reflecting the scarcity of naturally occurring hydrazines, common building blocks for the synthesis of these heterocycles. The pyridazine structure is a popular pharmacophore which is found within a number of herbicides such as credazine, pyridafol and pyridate. It is also found within the structure of several drugs such as cefozopran, cadralazine, minaprine, pipofezine, hydralazine, and cilazapril.

Syntheses[edit]

In the course of his classic investigation on the Fischer indole synthesis, Emil Fischer prepared the first pyridazine via the condensation of phenylhydrazine and levulinic acid.[2] The parent heterocycle was first prepared by oxidation of benzocinnoline to the pyridazinetetracarboxylic acid followed by decarboxylation. A better route to this otherwise esoteric compound starts with the maleic hydrazide. These heterocycles are often prepared via condensation of 1,4-diketones or 4-ketoacids with hydrazines.[3]

References[edit]

  1. ^ Gumus, S. (2011). "A computational study on substituted diazabenzenes" (PDF). Turk J Chem 35: 803–808. 
  2. ^ Fischer, E. (1886). "Indole aus Phenylhydrazin". Justus Liebigs Annalen der Chemie 236 (1-2): 126–151. doi:10.1002/jlac.18862360107. 
  3. ^ Tišler, M.; Stanovnik, B. (1968). "Pyridazines". Advances in Heterocyclic Chemistry 9: 211–320. doi:10.1016/S0065-2725(08)60374-8.