| 摘要 |
Compounds of the formula <IMAGE> wherein R1 is hydrogen or alkyl of 1 to 4 carbon atoms; and R2 is pyridyl, phenyl or mono-, di- or tri-substituted phenyl, where the substituents are alkyl of 1 to 2 carbon atoms, alkoxy of 1 to 2 carbon atoms, fluorine, chlorine, bromine, trifluoromethyl, nitro, benzyloxy or hydroxyl. The compounds are useful as nootropics. |
