[3] It made it to phase III clinical trials before being discontinued.

Catalytic hydrogenation serves to reduce the pyridine ring to a piperidine of undefined stereochemistry (3).

Treatment of that intermediate with Raney nickel reduces the cyano group to the corresponding primary amine; this product then undergoes an internal ester-amine interchange to yield the cyclized lactam (5).

Resolution of this product as its mandelate salt then yields (10) as a single enantiomer.

Rxn of that product with succinic anhydride converts the pendant amine to a succinimide, affording the anxiolytic agent sunepitron (1).