SYNTHESIS OF 6-DEOXY-5-THIO-D-GLUCOSE

Three routes were investigated for the conversion of D-glucose into th e title compound. In the first approach, reduction of the 5,6-thiirane ring of epithio-1,2-O-isopropylidene-alpha-D-glucofuranose (17) as we ll as that of its 3-O-allyl derivative (13) with lithium aluminium hyd ride was investigated; 17 afforded the corresponding 6-deoxy derivativ e besides di-, tri-, and poly-mers, whereas only polymers were formed from 13, In the second approach, the oxirane ring of ,6-anhydro-1,2-O- isopropylidene-beta-L-idofuranose was reduced by sodium borohydride an d the resulting 6-deoxy derivative was converted into the 5-thiobenzoa te; the corresponding hex-4-enofuranose was formed as a byproduct. In the third approach partial mesylation of methyl 5-thio-alpha-D-glucopy ranoside was attempted, but the 6-mesylate 27 could be isolated only i n modest yield (28%) together with rearranged 2,5-thioanhydromannofura noside derivatives. The mechanism of this rearrangement is discussed i n detail, The 6-mesylate 27 was converted via the 6-iodo derivative in to the title compound. (C) 1996 Elsevier Science Ltd.