Phthalazine

Phthalazine[1]
IUPAC name

Phthalazine
Other names

Benzo-orthodiazine
2,3-Benzodiazine
Benzo[d]pyridazine
Identifiers
CAS number 253-52-1
PubChem 9207
Jmol-3D images Image 1
Properties
Molecular formula C8H6N2
Molar mass 130.15 g/mol
Appearance Pale yellow needles
Melting point

90-91 °C
Boiling point

315-317 °C (decomposition)
Solubility in water Miscible
Acidity (pKa) 3.39[2]
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Phthalazine, also called benzo-orthodiazine or benzopyridazine, is a heterocyclic organic compound with the molecular formula C8H6N2. It is isomeric with quinoxaline, cinnoline and quinazoline.

Contents

Synthesis

Phthalazine can be obtained by the condensation of w-tetrabromorthoxylene with hydrazine, or by the reduction of chlorphthalazine with phosphorus and hydroiodic acid.

Properties

It possesses basic properties and forms addition products with alkyl iodides.

Reactions

Upon oxidation with alkaline potassium permanganate it yields pyridazine dicarboxylic acid. Zinc and hydrochloric acid decompose it with formation of orthoxylylene diamine. The keto-hydro derivative phthalazone (C8H6ON2), is obtained by condensing hydrazine with orthophthalaldehydoacid. On treatment with phosphorus oxychloride, it yields a chlorphthalazine, which with zinc and hydrochloric acid gives isoindole (C8H7N), and with tin and hydrochloric acid, phthalimidine (C8H7ON), the second nitrogen atom being eliminated as ammonia.

References

  1. ^ Merck Index, 11th Edition, 7344.
  2. ^ Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.