PREPARATION OF 9,9-DISUBSTITUTED 4,5-DIAZAFLUORENES USEFUL AS COGNITIVE ENHANCERS

A novel synthesis of symmetric and nonsymmetric 9,9-disubstituted 4,5- diazafluorenes has been developed, These compounds have activity in bo th an in vitro acetylcholine release assay and in vivo rodent models o f learning and memory. Preparation of these compounds-involves a uniqu e aldol condensation between 4,5-diazafluoren-9-one (4) and 4-picoline . Reduction of aldol product 5 (5-(4-pyridinylmethylene)-5H-cyclopenta -[2, 1-b:3,4-b']dipyridine) provides monoalkylated diazafluorene 6 iny lmethyl)-5H-cyclopenta[2,1-b:3,4-b']dipyridine) which proved to be a k ey intermediate for synthesis of nonsymmetric analogs.