Semisynthetic aminoglycoside antibacterials. Part II. Synthesis of gentamicin X2 and related compounds

Abstract

Gentamicin X₂, naturally occurring aminoglycoside antibiotic produced as a minor component together with the clinically important gentamicin C complex by Micromonospora purpurea, has been synthesized by glycosylation of suitably protected garamine derivatives. The synthesis of the α-glycoside was accomplished by means of the Lemieux–Nagabhushan reaction as well as by using a Koenigs–Knorr reaction. The latter reaction was also used to prepare 4-O-β-analogue of gentamicin X₂. The syntheses of other analogues of gentamicin X₂, namely 4-O-[2-amino-2-deoxy-α-D-mannopyranosyl], 4-O-[2-amino-2-deoxy-α-D-galactopyranosyl], 4-O-[2-amino-2-deoxy-α- and -β-D-glucofuranosyl], 4′-O-[2-amino-2-deoxy-α-D-glucopyranosyl], 4-O-α-D-glucopyranosyl, 4-O-α-D-talopyranosyl, and 4-O-2-deoxy-α-D-galactopyranosyl derivatives of garamine, are also described.