Disclosed herein is a method for prophylaxis or treatment of a neurodegenerative disease associated with aggregation of amyloid-beta (Aβ) in a subject. The method includes the step of, administering to the subject an effective amount of a compound having formula (I),wherein, R1 is selected from the group consisting of —SC3H6OH, —SC2H4COOH, —SCH2CHOHCH3, —SCH2CHOHCH2OH, —S(C6H4)OH, —SC2H4OH, —OH, and —NHC2H4(NC2H4OC2H4) and R2 is H or CH3.