Preparation and Characterization of Porphyrin-Acridine Conjugates as Bifunctional Antitumor Agents

The porphyrin-acridine conjugates (22) and (23) were prepared by condensation of porphyrin (17) with the 9-aminoacridine derivative (6) or (15), respectively. The conjugate drugs were isolated by size-exclusion chromatography in yields of up to 35% and further purified by semipreparative h.p.l.c . to 98% purity. Characterization of the conjugates was effected by 1H n.m.r. and u.v./vis . spectroscopy, f.a.b. mass spectrometry and u.v./vis . diode array h.p.l.c. Attempts to condense acridine (6) or (15) to porphyrin (16), (18) or (19) resulted in the isolation of the porphyrin-acridine conjugates (20), (21), (24) and (25) in low yields (≤ 25%), but the products could not be obtained in a pure state. However, their presence was identified by several physical measurements.