Acridone

YELLOW CRYSTALLINE POWDER
Acridone is a member of the class of acridines that is 9,10-dihydroacridine substituted by an oxo group at position 9. It is a member of acridines and a cyclic ketone.
Dissolve ~1g in ca 1% NaOH (100mL), add 3M HCl to pH 4 when acridone separates as a pale yellow solid with m just above 350o (sharp). It can be recrystallised from large volumes of H2O to give a few mg. It is soluble in 160 parts of boiling EtOH (540 parts at 22o) [Albert & Phillips J Chem Soc 1294 1956]. Afew decigms are best crystallised as the hydrochloride from 400 parts of 10N HCl (90% recovery) from which the free base is obtained by washing the salt with H2O. A small quantity can be recrystallised (as the neutral species) from boiling AcOH. Larger quantities are best recrystallised from a mixture of 5 parts of freshly distilled aniline and 12.5 parts of glacial acetic acid. Acridone distils unchanged at atmospheric pressure, but the boiling point was not recorded, and some sublimation occurs below 350o. It has UV: 399nm. [see max Albert, The Acridines Arnold Press pp 201, 372 1966; for pKa see Kalatzis J Chem Soc (B) 96 1969, Beilstein 23/9 V 7.]