A compound having the following structure of: wherein: R 1 is H and R 2 is lower alkyl, wherein lower alkyl is a straight chain or branched chain alkyl radical of 1 to 6 carbon atoms; R 3 is H; Y represents a bond, an alkyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, trifluoromethyl, hydroxy, alkoxy, trifluoromethoxy, amino, monoalkylamino, and dialkylamino, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted heterocyclyl, or a group -(CR a R b) n -Q-(CR c R d) m -, wherein Q is O, S, or NR 6; W represents H, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted heterocyclyl, an optionally substituted cycloalkyl, a group -C -R 5, or a group -(CR c R d) p -CR e R f R g; R 5 represents an optionally substituted aryl, an optionally substituted heteroaryl, or an optionally substituted heterocyclyl; R 6 represents H, an optionally substituted alkyl, an optionally substituted aryl, or an optionally substituted heterocyclyl; R a, R b, R c, R d, R e, R f and R g are independently selected from the group consisting of H, halogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted heterocyclyl, or an optionally substituted aryl; n is an integer from 2 to 5; m is an integer from 0 to 4; p is an integer from 0 to 4; wherein Y-W is not tert-butyl when R 1 is H, and R 2 is methyl; and wherein W is not an unsubstituted phenyl when Y is CH 2, R 1 is H, and R 2 is methyl, or isopropyl; or an ester or a pharmaceutically acceptable salt thereof. R 1 is H and R 2 is lower alkyl, wherein lower alkyl is a straight chain or branched chain alkyl radical of 1 to 6 carbon atoms; R 3 is H; Y represents a bond, an alkyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, trifluoromethyl, hydroxy, alkoxy, trifluoromethoxy, amino, monoalkylamino, and dialkylamino, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted heterocyclyl, or a group -(CR a R b) n -Q-(CR c R d) m -, wherein Q is O, S, or NR 6; W represents H, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted heterocyclyl, an optionally substituted cycloalkyl, a group -C -R 5, or a group -(CR c R d) p -CR e R f R g; R 5 represents an optionally substituted aryl, an optionally substituted heteroaryl, or an optionally substituted heterocyclyl; R 6 represents H, an optionally substituted alkyl, an optionally substituted aryl, or an optionally substituted heterocyclyl; R a, R b, R c, R d, R e, R f and R g are independently selected from the group consisting of H, halogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted heterocyclyl, or an optionally substituted aryl; n is an integer from 2 to 5; m is an integer from 0 to 4; p is an integer from 0 to 4; wherein Y-W is not tert-butyl when R 1 is H, and R 2 is methyl; and wherein W is not an unsubstituted phenyl when Y is CH 2, R 1 is H, and R 2 is methyl, or isopropyl; or an ester or a pharmaceutically acceptable salt thereof. R 5 represents an optionally substituted aryl, an optionally substituted heteroaryl, or an optionally substituted heterocyclyl; R 6 represents H, an optionally substituted alkyl, an optionally substituted aryl, or an optionally substituted heterocyclyl; R a, R b, R c, R d, R e, R f and R g are independently selected from the group consisting of H, halogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted heterocyclyl, or an optionally substituted aryl; n is an integer from 2 to 5; m is an integer from 0 to 4; p is an integer from 0 to 4; wherein Y-W is not tert-butyl when R 1 is H, and R 2 is methyl; and wherein W is not an unsubstituted phenyl when Y is CH 2, R 1 is H, and R 2 is methyl, or isopropyl; or an ester or a pharmaceutically acceptable salt thereof. or an ester or a pharmaceutically acceptable salt thereof.