Small molecules promoting sympathetic nerve regeneration

A compound of Formula (II):

• R2 is selected from the group consisting of C1-C4 straight or branched alkyl, C2-C4 straight or branched alkenyl, and C2-C4 straight or branched alkynyl;
• R3 is selected from the group consisting of C2-C8 straight or branched alkyl, C2-C6 straight or branched alkenyl, and straight or branched C2-C6 alkynyl, C3-C6 cycloalkyl, and —(CH2)n1-C3-C6 cycloalkyl;
• and
• R4 is selected from the group consisting of H, C1-C6 straight or branched alkyl, C2-C6 straight or branched alkenyl, C2-C6 straight or branched alkynyl, C3-C6 cycloalkyl, —(CH2)n2-C3-C6 cycloalkyl, C4-C6 cycloalkenyl, —(CH2)n2-C4-C6 cycloalkenyl, phenyl, —(CH2)n2-phenyl, 4-to 6-membered heterocyclyl, —(CH2)n2-4-to 6-membered heterocyclyl, heteroaromatic, and —(CH2)n2-heteroaromatic;
• with the proviso that, when R4 is hydrogen, then R3 is not methyl;
• or a pharmaceutically acceptable salt, pharmaceutically acceptable co-crystal, pharmaceutically acceptable ester, pharmaceutically acceptable solvate, hydrate, isomer, tautomer, isotope, polymorph, or a pharmaceutically acceptable prodrug thereof.