149402-15-3

Upstream product

• 14687-15-1 methyl L-fucopyranoside 
• 73-34-7 6-deoxy-L-galactose 
• 58479-61-1 tert-butylchlorodiphenylsilane 
• 24577-96-6 methyl 3,4-di-O-isopropylidene-α-L-fucopyranoside 

Downstream Products

• 149402-19-7 Methyl-2-O-tert-butyldiphenylsilyl-3,4-dideoxy-α-L-3-enofucopyranosid 
• 149402-16-4 methyl 2-O-tert-butyldiphenylsilyl-α-L-fucopyranoside 

Relevant academic research and scientific papers

Total Synthesis of Isokalafungins and Isonanaomycins

The total synthesis of isokalafungins (2) and isonanaomycins (12), the first members of a nonnatural group of benzoisochromanquinone antibiotics hydroxylated only at C-6, is described.Pathway A (Scheme 1) yields the separated (+/-)-cis and -trans diastereomers of 2 and 12 and is especially suited for modifications of the dihydropyrane ring.On pathway B the chirality of C-1 is performed by using 3,4,6-trideoxy-α-L-glycero-hex-3-enopyranosid-2-ulose (22) as a main building block, for the first time synthesized from L-fucose (Scheme 2).According to Scheme 3, condensation of 22 with the intermediate 23 gives the new 6-hydroxylated variants (1S,3S,4S)-isonanaomycin D (30) and (1R,3R,4R)-isokalafungin (2).Pathway B favours modifications of the phenolic ring, which can strongly influence the spectrum of activity.Unexpectedly, the shifting of the hydroxy group from C-9 to C-6 changes the antibacterial properties unessentially. Key Words: Antibiotics, unnatural / Benzoisochromanquinones / Isokalafungins / Isonanaomycins