N-heterocyclyl hydrazides as neurotrophic agents

A compound of Formula I,

• 20
• or a pharmaceutically acceptable salt thereof, wherein
• H1 is selected from the group consisting of a 4-membered nitrogen-containing heterocyclyl having 3 carbon ring atoms, a 5-membered nitrogen-containing heterocyclyl having 0 or 1 additional heteroatom ring member selected from O, S, and N, and a 6- or 7-membered nitrogen-containing heterocyclyl having 0, 1, or 2 additional heteroatom ring members selected from O, S, and N;
• H2 is a 5- or 6-membered heteroaryl;
• R1 is selected from urea, C1-C10 alkyl, aryl, heteroaryl, heterocyclyl, —C(O)R, —C(O)—C(O)R, —SO2R, and —P(O)(OR′)(OR″), wherein R, R′, and R″ are independently selected from the group consisting of alkyl, aryl, heteroaryl, and heterocyclyl;
• and
• R2 and R3 are independently hydrogen or C1-C10 alkyl.