Chemo-enzymatic synthesis of 1,4-oxazepanyl sugar as potent inhibitor of chitinase

N -Acetyl glucosamine 1 is selectively converted into 2 without protection of the other hydroxyl groups by allylation of the anomeric alkoxide in N , N -dimethylformamide containing lithium bromide. We use cell density cultures to produce the allylated derivative of penta- N -acetyl-chitopentaose by using 2 as the initial acceptor for the synthesis of 3 in vivo. Upon periodate oxidation, 3 is transferred to 4 . Compound 4 is quickly subjected to sodium borohydride reduction and NH 3 amination, which afforded the target compound 5 . In 5 -binding chitinase assay, it indicates that the chitinase is obviously inactivated by 5 with IC 50 = 4.7 μmol/L.