A Constitutional Synthesis of Chondrosamine

THE naturally occurring d-aminohexoses, glucosamine and chondrosamine, have long been known and are widely distributed in biologically important polysaccharides1. Any precise configuration of these substances, however, eluded chemists until 19392, when a derivative of glucosamine was synthesized by a method which proved conclusively that this amino-sugar was configurationally related to glucose, a conclusion confirmed independently by X-ray crystallographic methods3. The configuration of chondrosamine or its derivatives, however, has not been elucidated hitherto. It is generally believed that chondrosamine, the amino-sugar of cartilage4, is related to d-galactose, with its amino-group on the second carbon atom5, and it can certainly have only one of two configurations, namely, that of d-galactose or d-talose, since the amino-sugar can be transformed with loss of its amino-group into galactose phenylosazone6,7.