4-(9-tert-Butyl-3-azaspiro(5.5)undec-3-yl)-4'-fluoro-butyrophenone 64-58-4 BRN 1350881 BUTYROPHENONE, 4-(9-tert-BUTYL-3-AZASPIRO(5.5)UNDEC-3-YL)-4'-FLUORO-