TRICYCLIC HETEROAROMATIC SYSTEMS - SYNTHESIS OF 1,3-DISUBSTITUTED [1]BENZOPYRANO(4,3-B)PYRROL-4-ONES AND 1,2-DISUBSTITUTED [1]BENZOPYRANO(4,3-B)PYRROL-4-ONES AND STRUCTURE-ACTIVITY-RELATIONSHIPS AS BENZODIAZEPINE RECEPTOR LIGANDS

The synthesis of some 1,3- and 1,2- disubstituted [1]benzopyrano-pyrrol-4-ones is reported as well as their benzodiazepine receptor affinity, as measured by the ability to displace [H-3]flunitrazepam from its specific central binding. The structure-activity relationships on the whole series of disubstituted [1]benzopyrano-pyrrol-4-ones show the imporantance of the presence of the 1-aryl substituent and the size limitation of the 3-substituent. The size of the latter seems also to be important for the ''in vitro'' efficacy.