Deamination of Certain Amino Derivatives of Sugars and Sugar Alcohols

IT has already been observed 1 that the deamination of certain amino-sugar derivatives leads to the formation of ethylene oxide anhydro sugars. Thus, when 2-amino 4 : 6-benzylidene α-methyl-2-deoxyaltroside was treated with nitrous acid in acetic acid solution, deamination proceeded rapidly and smoothly and 2 : 3-anhydro 4 : 6-benzylidene α-methylalloside was precipitated. Similarly, the relatively insoluble 2 : 3-anhydro 4 : 6-benzylidene α-methylmannoside was obtained when 3-amino 4 : 6-benzylidene α-methyl-3-deoxyaltroside was deaminated. It might be argued that these two examples are exceptional cases, since both the anhydro sugar derivatives were precipitated during the deamination of the amines from which they were derived, and their formation may be due primarily to their insolubility. Such a possibility has now been eliminated, because several new cases of the formation of ethylene oxide anhydro sugar derivatives from amino-sugars have been observed in which all the reactants and products remained in solution during the reaction. Thus, deamination of 6-amino 1 : 2- iso -propylidene 6-deoxyglucose (I) in acetic acid solution gives 5 : 6-anhydro-1 : 2- iso propylidene glucose (II), and that of 4-amino 1 : 6-anhydro 4-deoxy-β- D -mannose 2 (III) under similar conditions furnishes 1 : 6-3 : 4-dianhydro-β- D -talose (IV). In this case the deamination is accompanied by Walden inversion at C 4 .