Regioselective monodeprotection of peracetylated carbohydrates

Abstract

This protocol describes the regioselective deprotection of single hydroxyls in peracetylated monosaccharides and disaccharides by enzymatic or chemoenzymatic strategies. The introduction of a one-pot enzymatic step by using immobilized biocatalysts obviates the requirement to carry out tedious workups and time-consuming purifications. By using this straightforward protocol, different per-O-acetylated glycopyranosides (mono- or disaccharides, 1-substituted or glycals) can be transformed into a whole set of differentially monodeprotected 1-alcohols, 3-alcohols, 4-alcohols and 6-alcohols in high yields. These tailor-made glycosyl acceptors can then be used for stereoselective glycosylation for oligosaccharide and glycoderivative synthesis. They have been successfully used as building blocks to synthesize tailor-made di- and trisaccharides involved in the structure of lacto-N-neo-tetraose and precursors of the tumor-associated carbohydrate antigen T and the antitumoral drug peracetylated β-naphtyl-lactosamine. We are able to prepare a purified monoprotected carbohydrate in between 1 and 4 d. With this protocol, the small library of monodeprotected products can be synthesized in 1-2 weeks.

Synthesis, Characterization and Antibacterial Susceptibility of some Benzenesulfonyl and N-Acetylsulfanilyl Derivatives of Methyl α-D-Glucopyranoside

“…Regioselective chemical monoacylation of carbohydrates is not easy due to their multifunctionality (Ren et al, 2014) and frequently, protection/deprotection sequences are needed (Guo and Ye, 2010;Filice et al, 2012). Acetylation and acylation of alcohols is a basic and widely used transformation in organic chemistry (Sartori et al, 2004), primarily to synthetically protect hydroxyl groups and as an aid to structurally elucidate poly-hydroxyl containing natural products such as oligosaccharides.…”

Stable metal-organic frameworks containing single-molecule traps for enzyme encapsulation

“…However, due to their one-dimensional (1D) channel structure, insufficient interactions between the inner channel surface of mesoporous silica and enzymes result in significant leaching during multiple cycles of use. Moreover, aggregation still occurs inside the channel [5][6][7][8][9] .…”

“…A range of solid supports have been explored for enzymes, such as sol gels, hydrogels, organic microparticles, and porous or non-porous inorganic supports 5 . However, there have been disadvantages associated with these supports, including very low protein loading in the non-porous systems and denaturation of enzymes in sol gels due to their brittle and disordered structures [5][6][7][8][9] . Mesoporous silica nanoparticles, which have a large pore size, high porosity and a very ordered structure, have been demonstrated as promising enzyme supports 5 .…”

Covalent Immobilization of Candida rugosa Lipase at Alkaline pH and Their Application in the Regioselective Deprotection of Per-O-acetylated Thymidine

“…This stable biocatalyst showed an excellent regioselectivity in the monodeprotection of per-O-acetylated thymidine, producing the 3-OH-5 1 -OAc-thymidine in 91% yield at pH 5. Therefore, this new biocatalyst represents an interesting alternative to the octyl-CRL preparation, which has been described as an excellent catalyst in nucleosides and especially in monosaccharides deprotection [18]. However, Ald-CRL presents the advantage of being an irreversible catalyst with high stability in the presence of solvent.…”

“…This phenomenon alters the open-closed movement of the oligopeptide lid during catalysis and the exact shape of the open structure which is translated in a significant modulation of the lipase properties. We have already observed these alterations in lipase enantioselectivity [31], and also in the regioselective deprotection of different glycoderivatives [18], and it has been recently observed in the production of 2-glyceryl derivatives [32].…”