Highly Diastereoselective Oxidation of 2-Amino-2-deoxy-1-thio-β-d-glucopyranosides:  Synthesis of Imino Sulfinylglycosides

Abstract

A synthetic route to imino thioglycosides and to imino sulfinylglycosides has been developed. A detailed study on the diastereoselective oxidation of 2-amino-2-deoxy-1-thio-beta-D-glucopyranosides is reported. It has been shown that the stereochemical outcome of the oxidation is highly dependent on the protective group of the amine function. While the oxidation of iminothioglycosides is slightly diastereoselective (up to 30% de in favor of the R(S) sulfoxide), a single isomer is obtained in the case of tetrachlorophthalimido derivatives. The absolute configuration of the sulfinyl glycoside was ascertained by NMR analysis using our recent model on the basis of the exo-anomeric effect corroborated by X-ray crystallography.

Conformational Flexibility and Dynamics of Two (1→6)‐Linked Disaccharides Related to an Oligosaccharide Epitope Expressed on Malignant Tumour Cells

“…General procedure for synthesis of 3 and 3 c: The donor ethyl 3,4,6-tri-Oacetyl-2-deoxy-2-N-tetrachlorophthalimido-1-thio-b-d-glucopyranoside [67] (0.17-0.26 mmol) and the acceptor methyl 2,3,4-tri-O-benzyl-a-d-mannopyranoside (1.1-1.5 equiv) were dissolved in CH 2 Cl 2 (40 mL; distilled from CaH 2 ) and the solution was purged with argon for 5 min. Molecular sieves (3 , powder) were added and the suspension was stirred for 15 min, then N-iodosuccinimide (NIS, 1.5-2.0 equiv) was added, followed by a sufficient amount of AgOTf to turn the solution dark red.…”

Synthesis of potential metal-binding group compounds to examine the zinc dependency of the GPI de-N-acetylase metalloenzyme in Trypanosoma brucei

“…These two anomers were separated by radial band chromatography to furnish the α-anomer 22 ( J 1,2  = 4.9 Hz) and the β-anomer 23 ( J 1,2  = 10.9 Hz) in 48% and 13% yields, respectively. The closing sequences 22 → 24 → 26 → 10 and 23 → 25 → 27 → 11 were then conducted without incident, essentially as those described for 9 ; the exception being 26 → 10 which was achieved via acid hydrolysis 24 (Scheme 2). …”

Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides

“…12 In some particular cases, high diastereoselectivities in the oxidation of thioglycosides have been achieved. 13 Witczak and coworkers 14 reported the oxidation of thiodisaccharides to sulfoxides or sulfones, derivatives that inhibit the proliferation of selected murine and human tumor cell lines. However, the sulfoxides were obtained as diastereomeric mixtures and the absolute conguration of the SO group has not been established.…”

“…[a] General procedure for the oxidation reaction of S-(1/4)-thiodisaccharides (12)(13)(14) to sulfoxides (15)(16)(17) A solution of mCPBA (77%, 32 mg, 0.141 mmol) in 2 mL of dry CH 2 Cl 2 was added dropwise to another solution of the thiodisaccharide (0.072 mmol) in 2 mL of ethyl ether at 0 C. The reaction was allowed to reach room temperature and aer 30 min of stirring was diluted with EtOAc (30 mL). To the mixture was added a solution of NaHSO 3 (satd.…”