1H- and 13C-n.m.r. studies of N-methyl-1-deoxynojirimycin, an α-d-glucosidase inhibitor

N-hydroxyethyl-piperidine and -pyrrolidine homoazasugars: preparation and evaluation of glycosidase inhibitory activity

An efficient and practical strategy for the synthesis of N-hydroxyethyl-1-deoxy-homonojirimycins 4 and 5 and N-hydroxyethyl-pyrrolidine homoazasugars 6 and 7 with full stereocontrol is being reported. The key step involved is the intermolecular Michael addition of benzylamine to D-glucose derived alpha,beta-unsaturated ester 8 followed by N-alkylation with ethyl bromoacetate. Reduction with LAH, acetylation, hydrogenation and protection with -Cbz group afforded compounds 14a and 14b. Removal of 1,2-acetonide functionality, hydrogenation and deacetylation afforded N-hydroxyethyl-D-gluco-1-deoxyhomonojirimycin (4) and N-hydroxyethyl-L-ido-1-deoxyhomonojirimycin (5), respectively. Compounds 14a and 14b on acetylation followed by removal of 1,2-acetonide functionality, sodium metaperiodate oxidation, hydrogenation and deacetylation gave 1,4,5-trideoxy-1,4-imino-N-hydroxyethyl-D-arabino-hexitol (6) and 1,4,5-trideoxy-1,4-imino-N-hydroxyethyl-L-xylo-hexitol (7), respectively. The glycosidase inhibition activity of compounds 4, 5, 6, 7, 16a and 16b was evaluated using sweet almond seed as a rich source of different glycosidases.

Isotope edited NMR studies of glycosidases: design and synthesis of a novel glycosidase inhibitor

N-13C-methyl-deoxynojirimycin was synthesized and used in isotope-edited NMR studies to probe the binding site of an alpha-glucosidase. Results from this analysis led to the design and preparation of a novel alpha-glucosidase inhibitor, N-glycyl deoxynojirimycin.

Systematic synthesis of N-methyl-1-deoxynojirimycin-containing, Le(x), Le(a), sialyl-Le(x) and sialyl-Le(a) epitopes recognized by selectins

A systematic synthesis of the N-methyl-1-deoxynojirimycin-containing oligosaccharides related to the Lewis x, Lewis a, sialyl-Lewis x and sialyl-Lewis a antigens has been achieved. The couplings of the suitably protected 1-deoxynojirimycin derivative 10 with methyl-1-thioglycosides (glycosyl donors) of L-fucose (11), D-galactose (15) and alpha-sialyl-(2-->3)-D-galactose (27) were carried out by using dimethyl(methylthio)sulfonium triflate (DMTST) or N-iodosuccinimide/trifluoromethanesulfonic acid (NIS/TfOH) as the glycosyl promoter. The resulting di- and tri-saccharides were each converted, by further cross glycosylations with 11, 15 or 27, to the desired tri- and tetra-saccharides 3-6 that inhibit the recognition between sialyl-Lewis x and selectins, a family of leukocyte cell adhesion molecules.

Conformational equilibria of 4-thiomaltose and nitrogen analogues of maltose in aqueous solutions

The 1H and 13C NMR data at neutral pH are presented for methyl 4-thio-beta- and alpha-maltoside (1 and 2) together with methyl 1-thio-alpha-D-glucopyranoside (3) and methyl 4-thio-alpha-D-glucopyranoside (4) as reference compounds. Furthermore, the NMR data at high and low pH are presented for the 4-amino-4-deoxy analogues of methyl alpha-maltoside (5 and 6) and the 5-amino-5-deoxy analogue (8) together with reference compounds methyl 4-amino-4-deoxy-alpha-D-glucopyranoside (7) and 1-deoxynojirimycin (9). The experimental NMR data are assigned by 1- and 2-dimensional spectroscopy at 500 and 600 MHz. The conformational preferences of the maltose analogues 1, 2, 5, 6 and 8 are evaluated by difference NOE experiments, 13C-1H long-range coupling constants, chemical-shift comparison with model compounds and hard-sphere force field calculations for 1 using Monte Carlo simulations. Additionally, the results are compared with extensive experimental NOE data for methyl alpha- and beta-maltoside and the results discussed in light of earlier studies.