Abstract: The present invention relates to compounds of formula I, in which X1, X2, X3, X4, Y1, Y2, Y3, Y4, R(3), R(4) and R(5) have the meanings mentioned in the specification, their preparation and their use, in particular in pharmaceuticals. The compounds effect the potassium channel or the IKs channel opened by cyclic adenosine monophosphate (cAMP) and are outstandingly suitable as pharmaceutical active compounds, for example for the prophylaxis and therapy of cardiovascular disorders, in particular arrhythmias, for the treatment of ulcers of the gastrointestinal region or for the treatment of diarrheal disorders.

Abstract: Families of Diels Alder adducts and of metal complexes of Diels Alder adducts, which are useful as particularly active compounds for use in photodynamic therapy, are disclosed. The Diels Alder adducts and a preferred family of metal complexes have the structures of Formulas 3 and 4, below: ##STR1## where R1, R2, R3 and R4 can be the same or different, and each is methyl, ethyl, an amino acid moiety which is a part of an amide produced by reaction between an amine function of a naturally occurring amino acid and a carbonyl function of the adduct, or a monoclonal antibody moiety which is attached to the adduct moiety through a carbonyl which is a part of an amide produced by reaction between an amine function of a monoclonal antibody and a CO.sub.2 R', CH.sub.2 CO.sub.2 R' or CH.sub.2 CH.sub.2 CO.sub.