6752-75-6

Upstream product

• 108-24-7 acetic anhydride 
• 3162-96-7 4,6-O-benzylidene-1-O-methyl-α-D-glucopyranoside 
• 75-36-5 acetyl chloride 
• 97-30-3 methyl-alpha-D-glucopyranoside 
• 1125-88-8 benzaldehyde dimethyl acetal 
• 2774-23-4 methyl 2-O-acetyl-4,6-O-benzylidene-α-D-mannopyranoside 
• 67-68-5 dimethyl sulfoxide 
• 3162-96-7 methyl-4,6-O-phenylmethylene-α-D-mannopyranoside 
• 617-04-9 (2R,3S,4S,5S,6S)-2-(hydroxymethyl)-6-methoxytetrahydro-2H-pyran-3,4,5-triol 
• 26295-65-8 (4aR,6S,7S,8S,8aR)-7,8-Bis-(1-ethoxy-ethoxy)-6-methoxy-2-phenyl-hexahydro-pyrano[3,2-d][1,3]dioxine 
• 4148-58-7 (4aR,6S,7S,8R,8aS)-6-Methoxy-2-phenyl-hexahydro-pyrano[3,2-d][1,3]dioxine-7,8-diol 
• 100-52-7 benzaldehyde 
• 110-86-1 pyridine 
• 65530-27-0 (2R,4aR,6S,8aS)-(+)-6-methoxy-2-phenyl-4,4a,6,8a-tetrahydropyrano[3,2-d][1,3]dioxine 

Downstream Products

• 102380-64-3 methyl-[O²,O³-bis-benzenesulfinyl-O⁴,O⁶-((R)-benzylidene)-α-D-glucopyranoside] 
• 7177-79-9 methyl 2,3-O-dibenzyl-4,6-O-benzylidene-α-D-glucopyranoside 
• 2774-23-4 methyl 2-O-acetyl-4,6-O-benzylidene-α-D-glucopyranoside 
• 2872-56-2 methyl 3-O-acetyl-4,6-O-benzylidene-α-D-glucopyranoside 
• 3162-96-7 4,6-O-benzylidene-1-O-methyl-α-D-glucopyranoside 
• 29868-43-7 methyl 2,3-di-O-acetyl-6-O-benzoyl-α-D-glucopyranoside 
• 56543-18-1 methyl 2,3-di-O-acetyl-4-O-benzoyl-α-D-glucopyranoside 
• 162284-50-6 methyl 2,3-di-O-acetyl-6-O-benzyl-α-D-glucopyranoside 
• 29868-42-6 methyl 2,3-di-O-acetyl-α-D-glucopyranoside 
• 51785-62-7 Benzoic acid (2R,3R,4S,5R,6S)-4,5-diacetoxy-6-methoxy-2-methyl-tetrahydro-pyran-3-yl ester 
• 51785-64-9 Benzoic acid (2S,4S,5R,6S)-4,5-diacetoxy-6-methoxy-tetrahydro-pyran-2-ylmethyl ester 
• 18929-80-1 methyl 2,3-di-O-acetyl-4-O-benzoyl-6-bromo-6-deoxy-α-D-glucopyranoside 
• 73139-31-8 methyl-2,3-di-O-acetyl-4-O-benzoyl-6-bromo-6-desoxy-α-D-altropyranoside 
• 1214746-77-6 methyl 2,3-di-O-acetyl-4-O-benzoyl-α-D-mannopyranoside 

Relevant academic research and scientific papers

In Situ Switching of Site-Selectivity with Light in the Acetylation of Sugars with Azopeptide Catalysts

We present a novel concept for the in situ control of site-selectivity of catalytic acetylations of partially protected sugars using light as external stimulus and oligopeptide catalysts equipped with an azobenzene moiety. The isomerizable azobenzene-peptide backbone defines the size and shape of the catalytic pocket, while the π-methyl-l-histidine (Pmh) moiety transfers the electrophile. Photoisomerization of the E- to the Z-azobenzene catalyst (monitored via NMR) with an LED (λ = 365 nm) drastically changes the chemical environment around the catalytically active Pmh moiety, so that the light-induced change in the catalyst shape alters site-selectivity. As a proof of principle, we employed (4,6-O-benzylidene)methyl-α-d-pyranosides, which provide a change in regioselectivity from 2:1 (E) to 1:5 (Z) for the monoacetylated products at room temperature. The validity of this new catalyst-design concept is further demonstrated with the regioselective acetylation of the natural product quercetin. In situ irradiation NMR spectroscopy was used to quantify photostationary states under continuous irradiation with UV light.

Acceleration and deceleration factors on the hydrolysis reaction of 4,6-O-benzylidene acetal group

The benzylidene acetal group is one of the most important protecting groups not only in carbohydrate chemistry but also in general organic chemistry. In the case of 4,6-O-benzylidene glycosides, we previously found that the stereochemistry at 4-position altered the reaction rate constant for hydrolysis of benzylidene acetal group. However, a detail of the acceleration or deceleration factor was still unclear. In this work, the hydrolysis reaction of benzylidene acetal group was analyzed using the Arrhenius and Eyring plot to obtain individual parameters for glucosides (Glc), mannosides (Man), and galactosides (Gal). The Arrhenius and Eyring plot indicated that the pre-exponential factor (A) and ΔS? were critical for the smallest reaction rate constant of Gal among nonacetylated substrates. On the other hand, both Ea/ΔH? and A/ΔS? were influential for the smallest reaction rate constant of Gal among diacetylated substrates. All parameters obtained suggested that the rate constant for hydrolysis reaction was regulated by protonation and hydration steps along with solvation. The obtained parameters support wide use of benzylidene acetal group as orthogonal protection of cis- and trans-fused bicyclic systems through the fast hydrolysis of the trans-fused benzylidene acetal group.

Diisopropylethylamine-triggered, highly efficient, self-catalyzed regioselective acylation of carbohydrates and diols

A diisopropylethylamine (DIPEA)-triggered, self-catalyzed, regioselective acylation of carbohydrates and diols is presented. The hydroxyl groups can be acylated by the corresponding anhydride in MeCN in the presence of a catalytic amount of DIPEA. This method is comparatively green and mild as it uses less organic base compared with other selective acylation methods. Mechanistic studies indicate that DIPEA reacts with the anhydride to form a carboxylate ion, and then the carboxylate ion could catalyze the selective acylation through a dual H-bonding interaction.

Ceric ammonium nitrate/acetic anhydride: A tunable system for the O-acetylation and mononitration of diversely protected carbohydrates

Esterification of a wide range of partially protected carbohydrate derivatives was achieved using acetic anhydride and a catalytic amount of ceric ammonium nitrate (CAN). Compatibility with the commonly used protecting groups was demonstrated, with the es

Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids

Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3-NaIO4-mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues.

2,4,6-Trichloro-1,3,5-triazine (TCT) mediated one-pot sequential functionalisation of glycosides for the generation of orthogonally protected monosaccharide building blocks

Orthogonally protected monosaccharide building blocks have been prepared using TCT in a one-pot multicomponent transformation. The process involves successive steps of arylidene acetalation, esterification and regioselective reductive acetal cleavage. High regioselectivity, scope for using a broad range of substrates, functional group tolerance, mild reaction conditions, easy handling process and wide application range are a few advantages of the current process.

Exciton chirality method in vibrational circular dichroism

The interaction of two IR chromophores yields a strong vibrational circular dichroism couplet whose sign reflects the absolute configuration of the molecule. We present a method to determine absolute configuration of a chiral molecule based on this couplet without need of theoretical calculation. Not only can this method analyze various molecules whose absolute configuration is difficult to determine by other spectroscopic methods, but also it can significantly enhance VCD signals.

Organosilicon-mediated regioselective acetylation of carbohydrates

Organosilicon-mediated, regioselective acetylation of vicinal- and 1,3-diols is presented. Methyl trimethoxysilane or dimethyl dimethoxysilane was first used to form cyclic 1,3,2-dioxasilolane or 1,3,2-dioxasilinane intermediates, and subsequent acetate-c

Tandem one-pot acetalation-acetylation for direct access to differentially protected thioglycosides and O-glycosides with p-toluenesulfonic acid

A new tandem one-pot acetalation-acetylation procedure is reported which streamlines routine protecting-group manipulation of carbohydrate molecules in production of differentially protected O- and thioglycosides. This new procedure eliminates the use of

Fe2(SO4)3·xH2O-catalyzed per-O-acetylation of sugars compatible with acid-labile protecting groups adopted in carbohydrate chemistry

Fully acetylated saccharides are inexpensive and very useful starting materials for the synthesis of many naturally occurring glycosides, oligosaccharides, and glycoconjugates. Ferric sulfate hydrate (Fe2(SO4)3·xH2O) was found to be a valuable Lewis acid promoter in the per-O-acetylation reaction of saccharides with acetic anhydride in 100% of conversion rate and 88-99% yields. Interestingly, the procedure is perfectly compatible with the presence of a variety of acid-labile protecting groups, such as isopropylidene, benzylidene, trityl, and TBDMS groups. The reactions were simply performed by stirring the mixture of a sugar with a slight excessive acetic anhydride in the presence of 2.0 mol % of Fe2(SO4)3·xH2O at rt and the pure products were obtained by a simple dilution of the reaction mixture with dichloromethane and washings with aqueous Na2CO3.