Prodrug platform useful to deliver amines, amides and phenols

A compound having formula (I):

• its stereoisomer, salt, hydrate, solvate, or crystalline form thereof;
• wherein,
• Ar is independently selected from the group consisting of optionally substituted aryl and heteroaryl;
• X is —NR′—;
• R′ is independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted aryl, and optionally substituted heteroaryl;
• and
• Q is a group that H-X-Q together represents a pharmaceutically active agent or prodrug thereof, and the pharmaceutically active agent is a chemical compound having at least one free aromatic amine or amide group,
• wherein H—X-Q together represents one selected from the group consisting of gemcitabine, tenofovir disoproxil, pamiparib, talazoparib, olaprib, veliparib, HY-14478, pioglitazone, lenvatinib, HY-103039, OS-9620, HY-103665, HY-123943, grapiprant, HY-10413, HY-50901, HY-10797, HY-103088, and apatinib.