We don't have synonyms for xanthines yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are xanthine, xanthenes and xanthones.
(n) :
(chemistry) Any of a group of alkaloids that include caffeine, theophylline, and theobromine as well as the parent compound, a precursor of uric acid found in many organs of the body.
(n) :
(chemistry) Any of a group of alkaloids that include caffeine, theophylline, and theobromine as well as the parent compound, a precursor of uric acid found in many organs of the body.