Phthalazine

Phthalazine[1]
Skeletal formula of phthalazine
Ball-and-stick model of the phthalazine molecule
Names
Preferred IUPAC name
Phthalazine[2]
Other names
Benzo-orthodiazine
2,3-Benzodiazine
Benzo[d]pyridazine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.005.422 Edit this at Wikidata
UNII
  • InChI=1S/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H ☒N
    Key: LFSXCDWNBUNEEM-UHFFFAOYSA-N ☒N
  • InChI=1/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H
    Key: LFSXCDWNBUNEEM-UHFFFAOYAE
  • C1=CC=C2C=NN=CC2=C1
Properties
C8H6N2
Molar mass 130.150 g·mol−1
Appearance Pale yellow needles
Melting point 90 to 91 °C (194 to 196 °F; 363 to 364 K)
Boiling point 315 to 317 °C (599 to 603 °F; 588 to 590 K) (decomposition)
Miscible
Acidity (pKa) 3.39[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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

Synthesis

Phthalazine can be obtained by the condensation of w-tetrabromorthoxylene with hydrazine, or by the reduction of chlorphthalazine with phosphorus and hydroiodic acid.[4]

Properties

It possesses basic properties and forms addition products with alkyl iodides.[4]

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[citation needed]. 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.[4]

References

  1. ^ Merck Index, 11th Edition, 7344.
  2. ^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 212. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  3. ^ 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.
  4. ^ a b c  One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Phthalazines". Encyclopædia Britannica. Vol. 21 (11th ed.). Cambridge University Press. p. 545.