Synthesis of d- and l-erythro 1,5-dithiopent-1-enopyranoside sulfonium salts and their evaluation as glycosidase inhibitors

A series of sulfonium salts derived from 1,5-dithiopent-1-enopyranosides was prepared in a three-step sequence from protected d- and l-erythrofuranoses. The key step is the nucleophilic displacement of a leaving group by a sulfur atom of carbohydrate-derived ketene dithioacetals. Such compounds were assayed for their properties as glycosidase inhibitors.

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Methyl 2-deoxy-5-[(S) methyl episulfonium]-1-thio-l-erythro-pent-1-enopyranoside trifluoromethanesulfonateC8H13F3O5S3[α]D20=-47.4 (c 0.90, MeOH)Source of chirality: l-arabinoseAbsolute configuration: (S), (3R,4R)

(5S,7R,8R)-7,8-Dihydroxy-2,3,4,6,7,8-hexahydrothiopyrano[1,2-a][1,3]dithiin-5-ium trifluoromethanesulfonateC9H13F3O5S3[α]D20=+92.2 (c 1.65, MeOH)Source of chirality: l-arabinoseAbsolute configuration: (5S,7R,8R)