Condensation of al-forms of sugars with thiobarbituric and iminobarbituric acids

Abstract

Fully acetylated al-D-glucose, al-D-galactose, and al-d-mannose condense with thiobarbituric acid in ethanol to give di-products, with deacetylation of the sugar portion, which latter, in the cases of the diproducts from glucose and galactose, is a (2, 6) anhydro ring. Condensation of al-D-glucose and al-D galactose with iminobarbituric acid in glacial acetic acid is of the crotonoid type, and gives acetylated monoproducts, while al-D mannose gives a di-product.