Compositions and methods for treating tauopathies

A compound of formula I:

• or a pharmaceutically acceptable salt thereof, wherein:
• X is C(R0)2, NR1, O or S;
• ring A is C6-10 aryl or 5- to 10-membered heteroaryl;
• ring B is C6-14 aryl or 5- to 10-membered heteroaryl;
• R0 is halogen, amino, hydroxyl, alkoxy, cyano, nitro, alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, or heteroaryl;
• R1 is hydrogen, sulfonyl, alkyl, aralkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, or heteroaryl;
• R2 and R3 independently are hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, or heteroaryl;
• or
• R2, R3, and the carbon atom to which they are connected, complete an oxo group (C═O);
• or
• R3, ring B, and the intervening atoms, complete a carbocyclyl, heterocyclyl, aryl, or heteroaryl;
• m is 0, 1, or 2, preferably 1, and
• provided the compound is not