1,3‐Dimethyl­isoguanine

The structure of 1,3‐dimethyl­isoguanine or 6‐amino‐1,3‐dimethyl‐1H‐purin‐2(3H)‐one], C₇H₉N₅O, has been redetermined and the correct assignment of H atoms on the heterocycle is now reported. Inter­molecular hydrogen‐bonding inter­actions confirm that this form is the correct mol­ecular structure; this form is also in agreement with an earlier reported structure of the trihydrate form.