Chemistry:Pyridazine
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| Names | |||
|---|---|---|---|
| Preferred IUPAC name
Pyridazine[1] | |||
| Systematic IUPAC name
1,2-Diazabenzene | |||
| Other names
1,2-Diazine
Orthodiazine Oizine | |||
| Identifiers | |||
3D model (JSmol)
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| 103906 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| EC Number |
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| 49310 | |||
PubChem CID
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| UNII | |||
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| Properties | |||
| C4H4N2 | |||
| Molar mass | 80.090 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Density | 1.107 g/cm3 | ||
| Melting point | −8 °C (18 °F; 265 K) | ||
| Boiling point | 208 °C (406 °F; 481 K) | ||
| miscible | |||
| Solubility | miscible in dioxane, ethanol soluble in benzene, diethyl ether negligible in cyclohexane, ligroin | ||
Refractive index (nD)
|
1.52311 (23.5 °C) | ||
| Thermochemistry | |||
Std enthalpy of
formation (ΔfH⦵298) |
224.9 kJ/mol | ||
| Hazards | |||
| GHS pictograms | 
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| GHS Signal word | Warning | ||
| H302, H315, H319, H335 | |||
| P261, P264, P264+265Script error: No such module "Preview warning".Category:GHS errors, P270, P271, P280, P301+317Script error: No such module "Preview warning".Category:GHS errors, P302+352, P304+340, P305+351+338, P319Script error: No such module "Preview warning".Category:GHS errors, P321, P330, P332+317Script error: No such module "Preview warning".Category:GHS errors, P337+317Script error: No such module "Preview warning".Category:GHS errors, P362+364Script error: No such module "Preview warning".Category:GHS errors, P403+233, P405, P501 | |||
| Flash point | 85 °C (185 °F; 358 K) | ||
| Related compounds | |||
Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
 verify (what is   ?)
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| Infobox references | |||
Pyridazine is an aromatic, heterocyclic, organic compound with the molecular formula C
4H
4N
2. It contains a six-membered ring with two adjacent nitrogen atoms.[3] It is a colorless liquid with a boiling point of 208 °C. It is isomeric with two other diazine (C
4H
4N
2) rings, pyrimidine and pyrazine.
Occurrence
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, and hydralazine.
Synthesis
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.[4] 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.[5]
References
- ↑ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 141. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
- ↑ "Pyridazine" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/9259#section=Safety-and-Hazards.
- ↑ Gumus, S. (2011). "A computational study on substituted diazabenzenes". Turk J Chem 35: 803–808. http://journals.tubitak.gov.tr/chem/issues/kim-11-35-5/kim-35-5-11-1012-875.pdf. Retrieved 2014-04-10.
- ↑ Fischer, E. (1886). "Indole aus Phenylhydrazin". Justus Liebigs Annalen der Chemie 236 (1–2): 126–151. doi:10.1002/jlac.18862360107. https://zenodo.org/record/1427407.
- ↑ Tišler, M.; Stanovnik, B. (1968). "Pyridazines". Advances in Heterocyclic Chemistry Volume 9. 9. pp. 211–320. doi:10.1016/S0065-2725(08)60374-8. ISBN 9780120206094.
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