Melatonin analogue prodrugs

Disclosed are compounds that can serve as melatonin analogue prodrugs and that are soluble in aqueous solvents. Melatonin or melatonin analogues having modifications to the indole moiety are coupled to a tertiary amine to form a quaternary amine such that there is a saturated two-carbon linkage between the carbonyl of the melatonin structure and the amine nitrogen. This structure is stable in acidic environments, but is unstable at basic or neutral pH. Therefore, these melatonin analogue prodrugs are stable in a vial at acidic pH, but will breakdown upon injection into the body to liberate the melatonin analogue and the tertiary amine, which is nontoxic. The melatonin analogue being not modified on the indole moiety exerts similar pharmacological properties as melatonin: antioxidation, sedation and anesthesia.