New long-wavelength perylenequinones: synthesis and phototoxicity of hypocrellin B derivatives

Five new derivatives of hypocrellin B were obtained from the reactions of h ypocrellin B with ammonia and ethanolamine. Their photophysical and photoch emical properties were investigated. The phototoxicity of one compound on A H cells irradiated with red light (lambda = 600-700 nm) was also studied. T heir significantly enhanced red absorptivities at wavelengths longer than 6 00 nm and singlet oxygen-generating function qualify them as promising phot odynamic therapy agents. (C) 2000 Elsevier Science B.V. All rights reserved .