Amino derivatives of mannuronic acid.

The widespread occurrence of amino derivatives of the sugars in products of plant and animal origin suggests the possibility that amino derivatives of the uronic acids may likewise be of importance. The uronic acids have the characteristic structures of both aldoses and aldonic acids, and hence, like the aldoses, might be expected to yield glycosyl amines [1] and like the lactones of the aldonic acids, to yield amides [2]. When mannuronic lactone was treated with ammonia in methanol in an endeavor to obtain the amide, a crystalline compound having the formula C6Hi205N2 separated from solution. The new compound, which has been found to be 1-aminomannuronamide crystallizes veiy readily and is suitable for the identification of mannuronic acid. It is fairly soluble in water, but aqueous solutions are somewhat unstable, and slowly hydrolyze with evolution of ammonia. On prolonged treatment with excess dilute acid, the optical rotation of a solution of 1-aminomannuronamide gradually changed from the levo to the dextro direction and attained the same value as that of a solution of mannuronic lactone similarly treated. Subsequently, mannuronic lactone was isolated from the solution. It is known that amino derivatives of the sugars in which the substitution is on an alcoholic carbon are extremely resistant to hydrolysis. Hence, the two amino groups in the new compound are not combined with the alcoholic carbons, and the