Melatonin can be deacetylated in a high-boiling alcohol with NaOH, to mexamine.
Then it becomes a reductive amination endeavor, stepwise, at temps < 15 C. Not particularly hazardous, but the latter aspect is crucial, to avoid pictet-spengler cyclization.
"Nothing is true, everything is permitted." ~ hassan i sabbah
"Experiments are the only means of attaining knowledge at our disposal. The rest is poetry, imagination." -Max Planck