The reaction of phenylhydrazine with squaric acid: A model for carbohydrate osazone formation

Article abstract of DOI:10.1016/0008-6215(93)84205-K

The reaction of squaric acid (1) with phenylhydrazine yields cyclobutanetetraone poly(phenylhydrazones) (2-4), as reported earlier, as well as squaric acid derivatives, reported here. The latter products are a salt, 1,3-dianilinocyclobutenediylium-2,4-dio