Alternative synthesis and antibacterial evaluation of 1,5-dideoxy-1,5-imino-l-rhamnitol

• Selective oxidation oxidation of a secondary alcohol in the presence of a hemiacetal is reported.
• Stereoselective reduction ketone reduction is reported.
• Antibacterial assays of the title compound are reported.
• Efficient synthesis of the title compound is reported.

A convenient synthesis is described of 5-azido-5-deoxy-2,3-O-isopropylidene-l-rhamnofuranose from l-rhamnose in seven steps and 17% overall yield. A key feature of the synthesis is the selective oxidation of the secondary alcohol in 2,3-O-isopropylidene-l-rhamnofuranose in the presence of the hemiacetal to give the corresponding ketone in good yield using the Parikh–Doering reagent. 5-Azido-5-deoxy-2,3-O-isopropylidene-l-rhamnofuranose is then converted by a literature protocol to 1,5-dideoxy-1,5-imino-l-rhamnitol, which was found to have no significant antimicrobial activity against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Escherichia coli.

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