| abstract |
New compounds represented by the formula n n nor pharmaceutically acceptable salts or prodrugs thereof,n nwhereinn X 1 and X 2 are each independently selected from a CH group or a nitrogen atom; and R is an optionally substituted five or six membered nonaromatic carbocyclic ring or a nonaromatic or aromatic heterocyclic ring, whereby the ring is optionally condensed with a 6-membered, optionally substituted carbocyclic aromatic ring. |