For Abstract see ChemInform Abstract in Full Text.

Galacturonic Acid Derivatives. I. Galacturonates from Acetyl‐ and Isopropylidene‐D‐galactopyranoses Galacturonic acid derivatives to be employed as glycosyl donors in saccharide synthesis are prepared from galacturonic acid itself or from galactose. Various syntheses of 1,2,3,4‐tetra‐O‐acetyl‐D‐galactopyranuronic acids (6) with differently protected carboxyl group and attempts of their conversion into galacturonpyranosyl bromides are described. The starting materials were 1,2;3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose and acetylated galactopyranose derivatives, respectively.

ChemInform Abstract The reactivity of the title compounds (I) and their open-chain analogues, for example (IV), is investigated.

Die Thioxocarboxylate (I) reagieren mit den Halogenverbindungen (II), (IV), (VII), (VIII), (XI) und (XII) zu den entsprechenden kondensierten Heterocyclen (III), (V), (VI), (IX), (X) und (XIII).

Verbindungen des Typs (I), in denen die Iminogruppe durch Methylierung blockiert ist, werden mit den Aminen (II) und (IV) bzw. Hydrazin (VI) umgesetzt.