- A new method of orthoesterification, under kinetic control, at non-anomeric positions. Application to the D-glucose and D-mannose series and selective hydrolysis of the corresponding orthoesters
-
The reaction of ketene acetals with D-glucose, D-mannose, and their methyl glycosides is described as a new route to unusual cyclic orthoesters (at non anomeric positions). The reaction proceeds by preferential attack of the reagent on the primary hydroxyl group. The synthesis of strained rings (2,3-diequatorial orthoester) is possible. The resulting methoxyethylidene derivatives are very sensitive to hydrolysis, and mild conditions lead to hydroxyacetates that are potentially useful intermediates for carbohydrates synthesis.
- Bouchra,Calinaud,Gelas
-
-
Read Online
- Selective deprotection of trityl group on carbohydrate by microflow reaction inhibiting migration of acetyl group
-
The trityl group is an important and useful protecting group for primary hydroxy groups on carbohydrates. However, during deprotection, neighboring acetyl groups can easily migrate to the deprotected hydroxy groups. Hence, deprotection of trityl groups was optimized using a microreactor with regard to flow rate, reagent concentration, reaction time, and substrate concentration. The optimized microflow reaction conditions inhibited migration and could be applied to large-scale reactions and other substrates.
- Miyagawa, Atsushi,Tomita, Ryusuke,Kurimoto, Kenta,Yamamura, Hatsuo
-
supporting information
p. 556 - 562
(2016/05/02)
-
- Synthesis of uniformly deuterated n-dodecyl-β -d-maltoside (d39 -DDM) for solubilization of membrane proteins in TROSY NMR experiments
-
This work reports the first synthesis of uniformly deuterated n-dodecyl-β -D-maltoside (d39-DDM). DDM is a mild non-ionic detergent often used in the extraction and purification of membrane proteins and for solubilizing them in experimental studies of their structure, dynamics and binding of ligands. We required d39-DDM for solubilizing large α-helical membrane proteins in samples for [15N-1H]TROSY (transverse relaxation-optimized spectroscopy) NMR experiments to achieve the highest sensitivity and best resolved spectra possible. Our synthesis of d39-DDM used d7-D-glucose and d25-n-dodecanol to introduce deuterium labelling into both the maltoside and dodecyl moieties, respectively. Two glucose molecules, one converted to a glycosyl acceptor with a free C4 hydroxyl group and one converted to a glycosyl donor substituted at C1 with a bromine in the α-configuration, were coupled together with an α(1 → 4) glycosidic bond to give maltose, which was then coupled with n-dodecanol by its substitution of a C1 bromine in the α-configuration to give DDM. 1H NMR spectra were used to confirm a high level of deuteration in the synthesized d39-DDM and to demonstrate its use in eliminating interfering signals from TROSY NMR spectra of a 52-kDa sugar transport protein solubilized in DDM.
- Hiruma-Shimizu, Kazumi,Kalverda, Arnout P.,Henderson, Peter J. F.,Homans, Steve W.,Patching, Simon G.
-
p. 737 - 743
(2015/02/19)
-
- Syntheses and 1H- and 13C-Nuclear Magnetic Resonance Spectra of All Positional Isomers of Tetra-O-acetyl-D-glucopyranoses, and Their Monobenzyl and Monotrityl Derivatives
-
All the isomers of the tetra-O-acetyl-D-glucopyranoses, and their monobenzyl and monotrityl derivatives were synthesized and systematic 1H- and 13C-nuclear magnetic resonance (1H- and 13C-NMR) studies were carried out.Complete assignments of the 1H- and 13C-NMR signals were achieved by 1H- and 13C-decoupling techniques and by the use of a shift reagent and changes of solvents.Moreover, when necessary, 1H- and 13C-shift-correlated 2D NMR spectroscopy at higher frequency (Bruker AM 400) was applied.The shifts on deacetylation, benzylation, and tritylation were estimated on the basis of the 1H- and 13C-chemical shifts of these compounds, and the effects of deacetylation and benzyl- or trityl-substitution are discussed.Keywords - tetra-O-acetyl-D-glucopyranose; monobenzyl tetra-O-acetyl-D-glucopyranose; monotrityl tetra-O-acetyl-D-glucopyranose; 1H-NMR; 13C-NMR; deacetylation shift; benzylation shift; tritylation shift
- Utamura, Toshiko,Kuromatsu, Keiko,Suwa, Kiyoko,Koizumi, Kyoko,Shingu, Tetsuro
-
p. 2341 - 2353
(2007/10/02)
-