Phthalazine

Phthalazine^[1]
Names
	Preferred IUPAC name Phthalazine
	Other names Benzo-orthodiazine; 2,3-Benzodiazine; Benzo[d]pyridazine
Identifiers
CAS Number	253-52-1;
3D model (JSmol)	Interactive image;
ChemSpider	8852;
ECHA InfoCard	100.005.422
PubChemCID	9207;
UNII	91Y28DM24N;
CompTox Dashboard(EPA)	DTXSID9049407;
	InChI InChI=1S/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H Key: LFSXCDWNBUNEEM-UHFFFAOYSA-N; InChI=1/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H Key: LFSXCDWNBUNEEM-UHFFFAOYAE;
	SMILES C1=CC=C2C=NN=CC2=C1;
Properties
Chemical formula	C8H6N2
Molar mass	130.150g·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)
Solubility in water	Miscible
Acidity(pKa)	3.39
	Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa). verify(what is?) Infobox references

Phthalazine,also called benzo-orthodiazine or benzopyridazine, is aheterocyclic organic compoundwith the molecular formula C₈H₆N₂.It isisomericwith othernaphthyridinesincludingquinoxaline,cinnolineandquinazoline.

Synthesis

Phthalazine can be obtained by thecondensationof w-tetrabromorthoxylene withhydrazine,or by thereductionof chlorphthalazine withphosphorusandhydroiodic acid.^[4]

It possessesbasicproperties and forms addition products withalkyl iodides.^[4]

Upon oxidation withalkaline potassium permanganateit yieldspyridazine dicarboxylic acid.Zincandhydrochloric aciddecompose it with formation of orthoxylylene diamine. The keto-hydro derivativephthalazone(C₈H₆ON₂), is obtained by condensing hydrazine with orthophthalaldehydoacid^{[citation needed]}.On treatment withphosphorus oxychloride,it yields a chlorphthalazine, which withzincandhydrochloric acidgives isoindole (C₈H₇N), and withtinand hydrochloric acid, phthalimidine (C₈H₇ON), the secondnitrogen atombeing eliminated asammonia.^[4]

^Merck Index,11th Edition,7344.
^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.
^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.
^^a ^b ^cOne or more of the preceding sentences incorporates text from a publication now in thepublic domain:Chisholm, Hugh,ed. (1911). "Phthalazines".Encyclopædia Britannica.Vol. 21 (11th ed.). Cambridge University Press. p. 545.