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Synthesis of 7-O-(3-amino-2,3,6-trideoxy-alpha-L-lyxo-hexopyranosyl)-epsilon-(i so)rhodomycinones 16 and 17, and their 3'-morpholino derivatives are described. Glycosylation (trimethylsilyl triflate, 10:1 dichloro-methane-acetone, -35 degrees) of 1-O-tert-butyldimethylsilyl-2,3-6-trideoxy-4-O-p-nitrobenzoyl-3-trifl uoroacetamido-beta-L-lyxo-hexopyranose (4) with epsilon-rhodomycinone (epsilon-RMN, 5) or epsilon-isorhodomycinone (epsilon-isoRMN, 6) afforded 7-O-alpha-glycosyl-epsilon-RMN (9) and -epsilon-isoRMN (12) in high yield. The glycosyl donors 2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoroacetamido-L-lyxo++ +-hexopyrano se (2) or its 1-O-trimethylsilylated alpha-anomer 3 were less suitable for the glycosylation of these aglycons. Sapinification of 9 and 12 provided 16 and 17, respectively, which reacted with various 2,2'-oxydiacetaldehydes under conditions of reductive alkylation to give 3'-morpholinyl-epsilon-(iso)rhodomycins.

Synthesis of 7- O -(4-amino-2,4,6-trideoxy- and 7- O -(3,4-diamino-2,3,4,6-tetradeoxy-α- l - lyxo -hexopyranosyl)-4- O -methyl-β-rhodomycinones ( 31 and 33 ) are described. The glycosyl donors 2,4,6-trideoxy-1,3-di- O-p -nitrobenzoyl-4-trifluoroacetamido-β- l - lyxo -hexopyranose ( 14β ) and 2,3,4,6-tetradeoxy-1- O-p -nitrobenzoyl-3,4-bis(trifluoroacetamido)-β- l - lyxo -hexopyranose ( 23β ) were suitable for the glycosylation of 4- O -methyl-10- O-p -nitrobenzoyl-β-rhodomycinone by the trimethylsilyl triflate method. Saponification of the resulting 7- O -α-glycosyl-4- O -methyl-β-rhodomycinones gave 31 and 33 .

Glycosylation of benzyl 2,3,6-trideoxy-3-trifluoroacetamido-α- l - lyxo -hexopyranoside ( 6 ) with 3,4-di- O -acetyl-1,5-anhydro-2,6-dideoxy- l - lyxo -hex-1-enitol ( 1 ) or 4- O -acetyl-1,5-anhydro-3- O -benzyl-2,6-dideoxy- l - lyxo -hex-1-enitol ( 2 ) in the presence of trimethylsilyl triflate/triethylamine gave α-(1→4)-linked disaccharide derivatives 7 and 8 , respectively. In the presence of trimethylsilyl triflate only, 3,4-di- O -acetyl-1- O - tert -butyldimethylsilyl-2,6-dideoxy-β- l - lyxo -hexopyranose ( 3 ) and 6 gave mainly 7 . Condensation of 1 or 2 with 9 , obtained by O -deacylation of 8 , afforded benzyl [ O -(3,4-di- O -acetyl-2,6-dideoxy-α- l - lyxo -hexopyranosyl)-(1→4)- O -(3- O -benzyl-2,6-dideoxy-α- l - lyxo -hexopyranosyl)- (1→4)-(2,3,6-trideoxy-3-trifluoro-acetamido-α- l - lyxo -hexopyranoside)] ( 11 ) and its 3″- O -benzyl analogue 12 , respectively.