Process of preparing N-substituted aldonamides

摘要

A process of preparing aldonamides and N-substituted aldonamides which includes the steps of recovering a by-product of the process (an ammonium salt of an aldonic acid) and converting it into at least one starting material. Aldonolactone is reacted with a primary or secondary amine and the resulting solution containing the by-product of the reaction is treated with a solid base to obtain a solid aldonate salt and a second solution containing the starting amine and some aldonamide. The second solution may be recycled as part of the starting material mixture. Alternatively, the amine and the aldonamide may be recovered from the second solution, and the amine alone may be recycled. The solid salt of aldonic acid may be converted into aldonic acid, which in turn may be converted into aldonolactone. The obtained aldono-1,5-lactone may also be utilized as a starting ingredient in the synthesis according to the present invention.