A compound of Formula I, or a pharmaceutically acceptable salt, solvate, and/or ester thereof, wherein, X 1 is selected from the group consisting of -C -O-, -S -, and -S(O 2)-,-C NR 6 -; X 2 is selected from the group consisting of -O-, -NR 6 -C -NR 6 -, -OC NR 6 -, -NR 6 -, and -NR 6 C O-; L is selected from the group consisting of a covalent bond, alkylene, and - CHR 7 -; R 1 is selected from the group consisting of unsubstituted phenyl, phenyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano, unsubstituted heteroarylalkyl, wherein the heteroaryl portion thereof is thiazolyl, and substituted heteroarylalkyl, wherein the heteroaryl portion thereof is thiazolyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; one R 2 is unsubstituted benzyl, and the other R 2 is H or alkyl; R 3 is selected from the group consisting of unsubstituted tetrahydro-2 H- furo[2,3-b]furanyl; unsubstituted tetrahydrofuranyl; unsubstituted thiazolyl, thiazolyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; unsubstituted thiazolylmethyl and thiazolylmethyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; R 4 is H or alkyl; R 5 is selected from the group consisting of H, alkyl, and benzyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, benzyl, alkoxy, benzyloxy, -O-CH 2 -pyridyl, halo, hydroxyl, amino, haloalkyl, and cyano; each R 6 is independently selected from the group consisting of H, alkyl, and cycloalkyl; and R 7 is selected from the group consisting of H, alkyl, substituted alkyl, and heterocyclylalkyl; wherein each aryl, heteroaryl, cycloalkyl, heterocyclyl, cycloalkylalkyl, heterocyclylalkyl, arylalkyl, and heteroarylalkyl of R 1, R 2, R 3, R 4, R 5, R 6 and R 7 is unsubstituted or substituted. X 1 is selected from the group consisting of -C -O-, -S -, and -S(O 2)-,-C NR 6 -; X 2 is selected from the group consisting of -O-, -NR 6 -C -NR 6 -, -OC NR 6 -, -NR 6 -, and -NR 6 C O-; L is selected from the group consisting of a covalent bond, alkylene, and - CHR 7 -; R 1 is selected from the group consisting of unsubstituted phenyl, phenyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano, unsubstituted heteroarylalkyl, wherein the heteroaryl portion thereof is thiazolyl, and substituted heteroarylalkyl, wherein the heteroaryl portion thereof is thiazolyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; one R 2 is unsubstituted benzyl, and the other R 2 is H or alkyl; R 3 is selected from the group consisting of unsubstituted tetrahydro-2 H- furo[2,3-b]furanyl; unsubstituted tetrahydrofuranyl; unsubstituted thiazolyl, thiazolyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; unsubstituted thiazolylmethyl and thiazolylmethyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, halo, hydroxyl, amino, haloalkyl, and cyano; R 4 is H or alkyl; R 5 is selected from the group consisting of H, alkyl, and benzyl substituted with one or more substituents selected from the group consisting of alkyl, substituted alkyl, benzyl, alkoxy, benzyloxy, -O-CH 2 -pyridyl, halo, hydroxyl, amino, haloalkyl, and cyano; each R 6 is independently selected from the group consisting of H, alkyl, and cycloalkyl; and R 7 is selected from the group consisting of H, alkyl, substituted alkyl, and heterocyclylalkyl; wherein each aryl, heteroaryl, cycloalkyl, heterocyclyl, cycloalkylalkyl, heterocyclylalkyl, arylalkyl, and heteroarylalkyl of R 1, R 2, R 3, R 4, R 5, R 6 and R 7 is unsubstituted or substituted.