Pterin is a heterocyclic compound composed of a pteridine ring system, with a "keto group" (a lactam) and an amino group on positions 4 and 2 respectively. It is structurally related to the parent bicyclic heterocycle called pteridine.
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.