7370. Phthalazine

Nomenclature

CAS number: 253-52-1
2,3-Benzodiazine; benzo[d]pyridazine; β-phenodiazine.
C8H6N2; mol wt 130.15.
C 73.83%, H 4.65%, N 21.52%.

Description and references

Prepd by reduction of 1-chlorophthalazine with hydriodic acid and red phosphorus: Gabriel, Eschenbach, Ber. 30, 3024 (1897); Paul, Ber. 32, 2015 (1899); by redn of 1-hydrazinophthalazine: Armarego, J. Appl. Chem. 11, 70 (1961); from o-phthalaldehyde + hydrazine sulfate: Smith, Otremba, J. Org. Chem. 27, 879 (1962); from 1,2-benzodinitrile: Carter, Cheeseman, Org. Prep. Proced. Int. 6, 67 (1974).

Chemical structure

Properties

Pale yellow needles from ether, mp 90-91°. bp 315-317° (dec); bp29 189°; bp17 175°. uv max (water): 218, 261, 292, 305 nm (log ε 4.83, 3.53, 3.18, 3.11). Freely sol in water; sol in ethanol, methanol, benzene, ethyl acetate; less sol in ether. Practically insol in ligroin.

Derivative

Hydrochloride.
C8H6N2.HCl; mol wt 166.61.
C 57.67%, H 4.23%, N 16.81%, Cl 21.28%.

Properties

Needles from ether, mp 231° (efferv).