1) Simple aromatic ring 
Münchnone (synonyms: 1,3-oxazolium-5-oxide; 1,3-oxazolium-5-olate; anhydro-5-hydroxy-1,3-oxazolium hydroxide; 5-hydroxy-1,3-oxazolium hydroxide, inner salt) is a mesoionic heterocyclic aromatic chemical compound. == Synthesis and reactivity == The first preparation of a münchnone derivative was reported in 1958 by Lawson & Miles by cyclodehydrat...