Carbohydrate components for modified anthracyclines: synthesis of derivatives of 3-amino-3,4,6-trideoxy-L-lyxo- and -L-xylo-hexose, and attempts at fluorination of C-2.

Two new trideoxyglycosides, methyl 3,4,6-trideoxy-3-nitro-alpha-L-lyxo-hexopyranoside (7) and its alpha-L-arabino isomer, as well as the known alpha-L-xylo isomer (15), were synthesized from methyl 3,6-dideoxy-3-nitro-alpha-L-glucopyranoside (1) by methods involving elimination and reduction processes in mesylates prepared from 1. Catalytic hydrogenation of 7 and 15 gave the new and the known aminodeoxyglycosides, respectively, both of which were N-(trifluoroacetyl)ated and sub-subsequently O-(trifluoromethylsulfonyl)ated. Various attempts to effect displacement by fluoride ion in the N-protected 2-triflates so obtained, and also in a related 3-azido-2-triflate, were unsuccessful as far as fluorination at C-2 was concerned. Among other products, two new 2-enopyranosides resulting from elimination of triflic acid were obtained.