(pyridinylmethyl)butanediamine derivatives that chelate copper

A compound of formula:

• wherein R1, R2, R3 and R4 are chosen independently from hydrogen, (C1-C6)alkyl, (C1-C6)oxaalkyl, and (C1-C6)aminoalkyl, or two adjacent R1, R2, R3 and R4 may form a five-, six-, or seven-membered ring, said five-, six-, or seven-membered ring optionally substituted with one or two substituents chosen from halogen, cyano, hydroxy, (C1-C6)alkyl, (C1-C6)oxaalkyl, and (C1-C6)aminoalkyl;
• A is a polycyclic ring system of up to five rings, optionally substituted with one or more substituents chosen from halogen, hydroxy, (C1-C6)alkyl, oxo, (C1-C6)oxaalkyl, carboxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkoxycarbonyl(C1-C6)alkyl, carboxy(C1-C6)alkyl, amino, and (C1-C6)aminoalkyl;
• n is zero or one;
• and
• p is one or two;
• with the proviso that, when R1, R2, R3, and R4 are all hydrogen, p is one, and n is zero, the polycyclic ring system A is not a perhydrocyclopenta[a]phenanthrene of formula
• attached at the 3-position as shown, in which a substituent at 17 is —CH(CH3)CH2CH2COOH, —CH(CH3)CH2CH2COOCH3, —CH(CH3)CH2CH2CH(OSO3H)CH(CH3)2,