Synthesis of Partially O-Acetylated N-Acetylneuraminic Acid Using Regioselective Silyl Exchange Technology
نویسندگان
چکیده
Postglycosylation acetylation of sialic acid imparts unique roles to sialoglycoconjugates in mammalian immune response making structural and functional understanding of these analogues important. Five partially O-acetylated Neu5Ac analogues have been synthesized. Reaction of per-O-silylated Neu5Ac ester with AcOH and Ac2O in pyridine promotes regioselective silyl ether/acetate exchange in the following order: C4 (2°) > C9 (1°) > C8 (2°) > C2 (anomeric). Subsequent hydrogenolysis affords the corresponding sialic acid analogues as useful chemical biology tools.
منابع مشابه
Integrating ReSET with Glycosyl Iodide Glycosylation in Step-Economy Syntheses of Tumor-Associated Carbohydrate Antigens and Immunogenic Glycolipids
Carbohydrates mediate a wide range of biological processes, and understanding these events and how they might be influenced is a complex undertaking that requires access to pure glycoconjugates. The isolation of sufficient quantities of carbohydrates and glycolipids from biological samples remains a significant challenge that has redirected efforts toward chemical synthesis. However, progress t...
متن کاملHNO3/N,N-Diethylethanaminium-2-(Sulfooxy)Ethyl Sulfate as an Efficient System for the Regioselective of Aromatic Compounds
N,N-diethylethanaminium-2-(sulfooxy) ethyl sulfate was synthesized and used as an efficient, green, and recyclable catalyst and solvent for the nitration of aromatic compounds by nitric acid at 80oC
متن کاملEfficient chemoenzymatic synthesis of biotinylated human serum albumin-sialoglycoside conjugates containing O-acetylated sialic acids.
Sialyl Tn (STn) and sialyl lactoside derivatives containing O-acetylated sialic acid residues have been chemoenzymatically synthesized using a one-pot three-enzyme system and conjugated to biotinylated human serum albumin (HSA) using an adipic acid para-nitrophenyl ester coupling reagent. This approach provides an efficient and general protocol for preparing carbohydrate-protein conjugates cont...
متن کاملMetabolism and role of O-acetylated sialic acids.
In the still growing family of sialic acids with more than 40 different derivatives of neuraminic acid, the interest of the scientific community is increasingly directed towards the O-acetylated species. In the past two decades it evolved that O-acetylated sialic acids play fundamental roles in the development of organisms, in the regulation of the immune system, in cancer processes and many ot...
متن کاملLewis acid-catalyzed regioselective synthesis of chiral α-fluoroalkyl amines via asymmetric addition of silyl dienolates to fluorinated sulfinylimines.
A tunable and highly regio- and diastereoselective addition of acyclic silyl dienolates 2 to several α-fluoroalkyl sulfinylimines 1 was developed. By appropriate choice of the Lewis acid catalyst, two new chiral α-fluoroalkyl amines 3 and 4 were obtained in good yields and excellent diastereoselectivities (up to >99 : 1 dr), respectively.
متن کامل