A novel method for the preparation of amino-substituted hypocrellin B.

A series of amino-substituted hypocrellins derived from hypocrellin B (HB) were synthesized by a novel mild method, in which the peri-hydroxylated perylenequinone structure of hypocrellin was preserved by the reaction of HB with an amine. The red absorption of the resulting products was significantly enhanced relative to the parent hypocrellins, which will significantly improve its photodynamic therapy effectiveness.