7-[4-[4-(2-methylphenyl)piperazin-1-yl]butoxy]-3,4-dihydro-1H-1,8-naphthyridin-2-one 7-[4-[4-(2-methylphenyl)-1-piperazinyl]butoxy]-3,4-dihydro-1H-1,8-naphthyridin-2-one