A method for treating a condition selected from Alzheimer's disease, mild cognitive impairment, age-associated dementia, and frontotemporal dementia, comprises administering to a patient in need of such treatment a safe and effective amount of a compound having the formula:
wherein R is selected from hydrogen, alkyl, alkoxy, arylalkyl, aryloxyalkyl, cinnamyl and acyl; and R1 and R2 are independently selected from hydrogen, alkyl, alkoxy, hydroxy, halogen, cyano, amino and nitro; with the proviso that if R is methyl, R1 and R2 are not both hydrogen; and the compound comprises pharmaceutically acceptable salts thereof.