Peer-to-Peer versus Federated Search: Towards more Interoperable Learning Object Repositories

The invention refers to a class of new compounds as well as a new process for making these compounds. The new compounds correspond to the general formula WHEREIN A1 represents a heterocyclic ring system which (a) contains at least one five-membered to six-membered heterocyclic ring having at least one ring oxygen atom and/or one ring sulphur atom, (b) is free of ring nitrogen atoms and of hydrogen atoms which are replaceable by alkali metal, and (c) is bonded by a ring carbon atom to a ring carbon atom of B1, or has two adjacent ring carbon atoms in common with two adjacent ring carbon atoms of B1, and wherein furthermore (a) B1 denotes a benzene ring or a heterocyclic ring of aromatic character containing five to six ring members, with these rings being permitted to contain further condensed-on aromatic, heterocyclic or hydroaromatic five-membered to six-membered rings, but preferably only one such ring, and (b) v denotes an integer from 1 to 2, and (c) wherein m denotes an integer from 1 to 4 in the case of a single bond between A1 and B1, and denotes the numbers 1 or 2 in the case of rings A1 and B1 being condensed with one another, and wherein E1 represents an aromatic carbocyclic or heterocyclic rings system containing five to six ring members, which may contain further condensed-on aromatic or hydroaromatic ring system of carbocyclic or heterocyclic nature, and may contain aromatic, araliphatic, cycloaliphatic, aliphatic or other non-chromophoric substituents, with the exception of methyl groups, which are capable of carbanion formation in the presence of alkali metal ions.