Glycosidase profiling with immobilised glycosidase-inhibiting iminoalditols—A proof-of-concept study

1-Deoxy-D-galactonojirimycins with dansyl capped N-substituents as β-galactosidase inhibitors and potential probes for GM1 gangliosidosis affected cell lines

Two simple and reliably accessible intermediates, N-carboxypentyl- and N-aminohexyl-1-deoxy-D-galactonojirimycin were employed for the synthesis of a set of terminally N-dansyl substituted derivatives. Reaction of the terminal carboxylic acid of N-carboxypentyl-1-deoxy-D-galactonojirimycin with N-dansyl-1,6-diaminohexane provided the chain-extended fluorescent derivative. Employing bis(6-dansylaminohexyl)amine, the corresponding branched di-N-dansyl compound was obtained. Partially protected N-aminohexyl-1-deoxy-D-galactonojirimycin served as intermediate for two additional chain-extended fluorescent 1-deoxy-D-galactonojirimycin (1-DGJ) derivatives featuring terminal dansyl groups in the N-alkyl substituent. These new compounds are strong inhibitors of d-galactosidases and may serve as leads en route to pharmacological chaperones for GM1-gangliosidosis.

Imino sugars and glycosyl hydrolases: historical context, current aspects, emerging trends

Forty years of discoveries and research on imino sugars, which are carbohydrate analogues having a basic nitrogen atom instead of oxygen in the sugar ring and, acting as potent glycosidase inhibitors, have made considerable impact on our contemporary understanding of glycosidases. Imino sugars have helped to elucidate the catalytic machinery of glycosidases and have refined our methods and concepts of utilizing them. A number of new aspects have emerged for employing imino sugars as pharmaceutical compounds, based on their profound effects on metabolic activities in which glycosidases are involved. From the digestion of starch to the fight against viral infections, from research into malignant diseases to potential improvements in hereditary storage disorders, glycosidase action and inhibition are essential issues. This account aims at combining general developments with a focus on some niches where imino sugars have become useful tools for glycochemistry and glycobiology.

1-Deoxynojirimycins with dansyl capped N-substituents as probes for Morbus Gaucher affected cell lines

Cyclization by double reductive amination of d-xylo-hexos-5-ulose with methyl 6-aminohexanoate gave (methoxycarbonyl)pentyl-1-deoxynojirimycin. Reaction of the terminal carboxylic acid with N-dansyl-1,6-diaminohexane provided the corresponding chain-extended fluorescent derivative. By reaction with bis(6-dansylaminohexyl)amine, the corresponding branched di-N-dansyl compound was obtained. Both compounds are strong inhibitors of d-glucosidases and could also be shown to distinctly improve, at sub-inhibitory concentrations, the activity of beta-glucocerebrosidase in a Gaucher fibroblast (N370S) cell-line through chaperoning of the enzyme to the lysosome.

2-Acetamino-1,2-dideoxynojirimycin-lysine hybrids as hexosaminidase inhibitors

Cyclisation by double reductive amination of 2-acetamino-2-deoxy-D-xylo-hexos-5-ulose with N-2 protected L-lysine derivatives provided 2-acetamino-1,2-dideoxynojirimycin derivatives without any observable epimer formation at C-5. Modifications on the lysine moiety gave access to lipophilic derivatives that exhibited improved hexosaminidase inhibitory activities.

Synthesis and Biological Evaluation of 1,5-Dideoxy-1,5-iminoxylitol–Amino Acid Hybrids as Xylosidase Inhibitors

1,5-Dideoxy-1,5-iminoxylitol–amino acid hybrids have been synthesized by cyclisation via a double reductive amination of xylo-pentodialdose and the respective amino groups of lysine as well as serine components. Further modification with aromatic substituents gave access to lipophilic derivatives. Kinetic studies revealed that all compounds exhibited better inhibitory properties against β-xylosidase from Thermoanaerobacterium sacharolyticum than the parent iminosugar.

1-Deoxygalactonojirimycin-lysine hybrids as potent D-galactosidase inhibitors

Cyclization by double reductive amination of L-arabino-hexos-5-ulose with suitably protected D- as well as L-lysine derivatives provided 1-deoxygalactonojirimycin lysine hybrids without any observable epimer formation at C-5. Modifications on the lysine moiety by acylation gave access to lipophilic derivatives which exhibited excellent D-galactosidase inhibitory activities.