Regioselective reactions of carbohydrates are complicated by the presence of several hydroxyl groups of similar reactivity in carbohydrate molecules. Despite the fact that primary hydroxyls react faster than others, selective acylation by known methods often requires special catalysts and environment-unfriendly reagents. The development of pathways for selective acetylation at the O-6 position is an important contribution to the study of naturally occurring carbohydrates.
Researchers from laboratory № 21 of Zelinsky Institute have proposed a convenient method for obtaining 6-O-acetyl derivatives of various thioglycosides. The acetylating agent is aqueous or anhydrous acetic acid; no additional catalysts were required. It should be also noted that the unreacted starting material can be easily recovered using column chromatography and put into the reaction again
P. I. Abronina, N. N. Malysheva, Al. I. Zinin, N. G. Kolotyrkina, E. V. Stepanova, and L. O. Kononov Catalyst-free regioselective acetylation of primary hydroxy groups in partially protected and unprotected thioglycosides with acetic acid RSC Adv., 2020, 10, 36836-36942. DOI: 10.1039/d0ra07360a.