A compound having Formula I or a pharmaceutically acceptable salt thereof, wherein: R 1 is -H, -C 1-6 alkyl, -OC 1-6 alkyl, -CH 2 F, -CH 2 OCH 3, -SC 1-6 alkyl, -CH 3, -CH 2 CH 3, -SCH(CH 3) 2, -CH 2 OH, -SCH 3, -OCH 3, -R 13 R 14, R 2 is -CH 3; R 3 is -CH 2 CH(CH 3) 2; R 4 is -CH 3; R 5 is -R 8 (CH 2) n (C=O) m -; R 6 is -CH 2 CH 3; R 8 is CH 2 O or CH 2; R 9 is -H, -C 1-5 alkyl, -C 2-4 fluoroalkyl, C 1-6 alkyl-heterocycle, cyanoalkyl, C 3-8 cycloalkyl, heterocycle, aryl, or cycloalkenyl, or R 9 taken together with R 11, R 10, and the N to which R 9 and R 10 are attached forms a heterocycle; R 10 is -H, -C 1-5 alkyl, -C 2-4 fluoroalkyl, C 1-6 alkyl-heterocycle, cyanoalkyl, C 3-8 cycloalkyl, heterocycle, aryl, or cycloalkenyl, or R 10 taken together with R 11, R 9, and the N to which R 9 and R 10 are attached forms a heterocycle; R 11 is O, NR 12, S q, CF 2, CH(OC 1-6 alkyl), C 1-5 alkylene, divalent C 3-8 cycloalkyl, divalent heterocycle, carbonyl, or taken together with R 9, R 10, and the N to which R 9 and R 10 are attached forms a heterocycle; R 12 is H, CH 3, or C 1-5 alkyl; R 13 is O, S, CH 2 O CH 2 S, CH 2 SO, or CH 2 SO 2; R 14 is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, CH 2 CH 2 N(CH 2 CH 3) 2, CH 2 CH 2 NH(CH 2 CH 3), heterocycle, or aryl; n = 0, 1, 2, 3, or 4; m = 0 or 1; p = 0 or 1; and q = 0, 1, or 2; wherein R 14 is optionally substituted with one or more groups independently selected from the group consisting of H, C 1-6 alkyl, halogen, hydroxyl, ester, sulfonamide, ketone, aldehyde, cycloalkyl, heterocycle, aryl, amine, heterocycle, amide, and guanidinyl; wherein the heterocycle comprising R 9, R 10, R 11, and the N to which R 9 and R 10 are attached is monocyclic or polycyclic; wherein "------" is a single bond or is absent; and with the provisos that when R 8 is CH 2 O then n is not 0 or 1; when p = 0 then R 11 and "------" are absent; and when R 11 and "------" are absent then R 9 is not directly linked to R 10. R 1 is -H, -C 1-6 alkyl, -OC 1-6 alkyl, -CH 2 F, -CH 2 OCH 3, -SC 1-6 alkyl, -CH 3, -CH 2 CH 3, -SCH(CH 3) 2, -CH 2 OH, -SCH 3, -OCH 3, -R 13 R 14, R 2 is -CH 3; R 3 is -CH 2 CH(CH 3) 2; R 4 is -CH 3; R 5 is -R 8 (CH 2) n (C=O) m -; R 6 is -CH 2 CH 3; R 8 is CH 2 O or CH 2; R 9 is -H, -C 1-5 alkyl, -C 2-4 fluoroalkyl, C 1-6 alkyl-heterocycle, cyanoalkyl, C 3-8 cycloalkyl, heterocycle, aryl, or cycloalkenyl, or R 9 taken together with R 11, R 10, and the N to which R 9 and R 10 are attached forms a heterocycle; R 10 is -H, -C 1-5 alkyl, -C 2-4 fluoroalkyl, C 1-6 alkyl-heterocycle, cyanoalkyl, C 3-8 cycloalkyl, heterocycle, aryl, or cycloalkenyl, or R 10 taken together with R 11, R 9, and the N to which R 9 and R 10 are attached forms a heterocycle; R 11 is O, NR 12, S q, CF 2, CH(OC 1-6 alkyl), C 1-5 alkylene, divalent C 3-8 cycloalkyl, divalent heterocycle, carbonyl, or taken together with R 9, R 10, and the N to which R 9 and R 10 are attached forms a heterocycle; R 12 is H, CH 3, or C 1-5 alkyl; R 13 is O, S, CH 2 O CH 2 S, CH 2 SO, or CH 2 SO 2; R 14 is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, CH 2 CH 2 N(CH 2 CH 3) 2, CH 2 CH 2 NH(CH 2 CH 3), heterocycle, or aryl; n = 0, 1, 2, 3, or 4; m = 0 or 1; p = 0 or 1; and q = 0, 1, or 2; wherein R 14 is optionally substituted with one or more groups independently selected from the group consisting of H, C 1-6 alkyl, halogen, hydroxyl, ester, sulfonamide, ketone, aldehyde, cycloalkyl, heterocycle, aryl, amine, heterocycle, amide, and guanidinyl; wherein the heterocycle comprising R 9, R 10, R 11, and the N to which R 9 and R 10 are attached is monocyclic or polycyclic; wherein "------" is a single bond or is absent; and with the provisos that when R 8 is CH 2 O then n is not 0 or 1; when p = 0 then R 11 and "------" are absent; and when R 11 and "------" are absent then R 9 is not directly linked to R 10.