Synthesis of the anhydrides of α-aminoacyl glucosamines

Abstract

The behaviour of the albumin glucosides and the mucus bodies known as mucins, mucinogens, mucoids , and hyalogens , on hydrolysis suggests the probability that these complex proteins would bear the same relation to the condensation products of the sugars or the amino-sugars with the amino-acids as the simpler proteins bear to the polypeptides. Consequently, the authors decided two years ago to make a start in the synthesis of the glucoproteins by preparing the condensation products of glucosamine with the amino-aliphatic acids, in order that their properties and behaviour towards ferments could be ascertained and compared with those of the degradation products of the glucoproteins and thereby throw some light on the constitution of these complex and important organic bodies. After many failures, the method of synthesis which we eventually adopted for the condensation of glucosamine with amino-aliphatic acids was somewhat similar to one of the methods employed by Emil Fischer and his co-workers in the synthesis of the polypeptides. In brief, the method consists in condensing α -bromoacyl haloids with glucosamine hydrochloride in the presence of sodium hydroxide, and then displacing the halogen in the resulting α -bromoacyl glucosamines by an amino-group through the action of cold aqueous ammonia, viz:- α -Bromoacyl Haloid + Glucosamine Hydrochloride. sodium ↓ hydroxide. α -Bromoacyl Glucosamine. aqueous ↓ ammonia. Anhydride of α -Aminoacyl Glucosamine.