Synthesis of chromogenic probes for detection and assay of diglycosidases

Diglycosidases represent a special group of glycoside hydrolases characterized by their unique way of hydrolysis of natural products, such as rutin, hesperidin, furcatin, vicianin, etc.[1] Four yet known diglycosidases, namely rutinosidase/hesperidinase, acuminosidase, vicianosidase, and primeverosidase may be considered as endo-β-glucosidases, [2] since they hydrolyze β-glycosidic bond between aglycone and glucose, with another saccharide moiety (e.g. rhamnopyranosyl, apiofuranosyl, xylopyranosyl, arabinopyranosyl) [3] bound in the position 6-O of the glucopyranoside ring.

In this work we synthesized two derivatives of natural disaccharides 4-nitrophenyl β-acuminoside (1) and 2-nitrophenyl β-robinobioside (2) as chromogenic probes of two diglycosidases – acuminosidase and robinobiosidase, respectively. The key steps of synthesis were glycosylations of appropriate peracetylated nitrophenyl glycosides previously deprotected in position 6, with peracetylated D-apiofuranosyl donor or D-rhamnopyranosyl donor, respectively. Two different glycosylation methods were used, resulting in good yields and excellent stereoselectivity. After deprotection of glycosylation products we obtained 43 % of 1 and 83% of 2 overall in two steps. We intend to use these compounds as chromogenic probes for two diglycosidases – acuminosidase and robinobiosidase.