A solution of 3-[2-(3-azabicyclo[3.2.2]non-3-yl)ethyl]-1,2,3,4-tetrahydro-8-methyl-9-nitro-5H-[1]benzopyrano[3,4-c]pyridin-5-one (10.5 g, 0.026 moles) in N,N-dimethylformamide (300 ml) is hydrogenated at 50 psi at 24° C. in the presence of Raney Nickel until the required amount of hydrogen has been taken up. The catalyst is filtered off and rinsed with hot N,N-dimethylformamide until free of organic material. The filtrate is slightly concentrated and cooled to give the product. Recrystallization from ethanol gave the product (5.1 g), mp 142°-143° C.
