Title:Synthesis of New Glycosylamine Derivatives based on Carbohydrates
Volume: 20
Issue: 2
Author(s): Hadi Jabbari*
Affiliation:
- Department of Chemistry, Payame Noor University, Tehran, P.O. Box 19395-4697, Iran
Keywords:
Carbohydrates, MgO/MeOH, Ac2O/AcONa, anomeric position, alkoxy N-methylglycosyl amine, methanol solvent.
Abstract:
Background: Glycosylamine play an important role in living organisms. Most plants
store their chemical resources in the form of inactive glycosides, which are broken down and converted
into sugar in the body of herbivores by hydrolyzing enzymes. Glycosylamine are obtained
from the secondary metabolism of plants and consist of two parts. One part of it contains sugar like
glucose and is inactive in most substances, and has a good effect on the solubility of the glycosylamine
derivatives and its absorption and even its transfer from one organ to another. The therapeutic
effect is related to the second part, which is called aglycan (or aglucan). Glycosylamine derivatives
form a large group of valuable medicinal substances, which at the same time include some of the
most dangerous and toxic substances in nature. These substances are present in many groups of
flowering plants. Glycosides are made in different ways in different metabolic pathways. These
materials have a complex and special chemical structure and leave special effects on the human
body. Glycosylamine derivatives are called O-glycosid, N-glycosid, S-glycosid in terms of atoms
coupling to anomeric carbon. Carbohydrate esterification reaction to prepare new glycosylamine
derivatives is one of the most important carbohydrate reactions. The anomeric position of carbohydrates
with strong leaving groups is very important for the preparation of glycosides. Preparation of
glycosylamine derivatives based on acetylated carbohydrates is the main purpose of this article. Different
carbohydrates were acetylated under mild conditions and high yields. The anomeric position
was deacetylated by a magnesium oxide heterogeneous catalyst in methanol solvent. In order to prepare
new glycosides acetylated/ deacytylated carbohydrate reacted with N-Methyl-(naphtha-2-
ylmethoxy)amine. The final product was identified by various spectroscopic methods.
Methods: Anhydrous sodium acetate (4 g) and α-D-glucose (28 mg, 5 g) were mixed. The mixture
was transferred to a 200 ml Round-bottom flask . Acetic acid (260 mg, 25 ml) was added to the
reaction mixture. The reaction mixture was heated in a boiling water bath for 2 h until complete
dissolution of the glucose. Then 100 ml of ice was added. After 1 hour, White crystals formed and
were washed with cold water. And then 1 mol of glucose pentaacetate per 50 ml of methanol was
dissolved by a magnetic stirrer. After thatMgO (0.2gr) was added to the reaction mixture. The reaction
mixture was refluxed at room temperature within 4-5 hours. After 5 hours, the solvent was
removed and separated by chromatography. It is then washed with hexane and crystallized by etherhexane.
And the final step reacted with N-Methyl- (naphtha-2-ylmethoxy) amine in order to prepare
new glycosylamine derivatives.
Results: Magnesium oxide in methanol solvent is one of the best effective catalysts in the deacetylation
of the anomer position of acetylated carbohydrates. It is done under ambient temperature and in
very easy conditions and makes carbohydrates susceptible to extensive chemical reactions. One of
these reactions is the formation of glycosides. Various carbohydrates are acetylated by acetic anhydride
in the presence of sodium acetate, and the anomeric position is deacetylated by a heterogeneous
catalyst. In order to prepare N-glycoside, the glycosides are reacted with N-alkoxy N-methylglycosyl
amine. The final products are identified by various spectroscopic methods.
Conclusion: Glucose, mannose, for example, were acetylated by acetic anhydride in the presence of
sodium acetate. And the anomeric position of pentaacetate glucose was selectively deacetylated with
magnesium oxide in a methanol solvent. Then, the reaction for the preparation of glycosylamine derivatives
was carried out under very mild and easy conditions. The aminoglycosides synthesized in
this article are used as raw materials for the synthesis of a wide range of antibacterials.
