Abstract
Purpose: To describe a chemoenzymatic approach joining an enzymatic
regioselective hydrolysis of peracetylated N-acetyl-α-D-glucosamine (A)
with a mild controlled acyl relocation which resulted 2-acetamido-2
deoxy-1,3,6-tri-O-acetyl-α-D-glucopyranose (1B).
Methods: Immobilization of
lipase on decaoctyl (DSEOD) and octyl-agarose (OSCL) was carried out as
reported by the work of Bastida et al. The newly developed RP-HPLC method for examining
the enzymatic hydrolysis was carried out isocratically utilizing a HPLC system.
Results: The new approach resulted the target compound (B)
in 95% yield after purification utilizing flash column chromatography. Candida
rugosa-lipase immobilized ondecaoctyl-sepabeads was the best catalyst in
terms of activity and region-selectivity in the hydrolysis of substrate (A),
delivering the deacetylation at C6 position (98% general yield).
Also,
a reversed-phase high-performance
liquid-chromatographic
(RP-HPLC) method for controlling the region-selective hydrolysis of
peracetylated N-acetyl-α-D-glucosamine (A) with a mild monitored
acyl movement which led to
2-acetamido-2-deoxy-1,3,6-tri-O-acetyl-α-D-glucopyranose (1B) has
additionally been developed. The developed RP-HPLC method was utilized as
fingerprints to follow the hydrolysis of substrate (A) and to determine its
purity and additionally yield. Furthermore, the acquired compound (B)
was further purified by flash chromatography. Compound (B) was further
characterized utilizing 1HNMR and mass spectrometry.
Conclusion: An efficient chemoenzymatic
procedure to optimize the preparation of peracetylated lactosamine B
containing acetyl ester as extraordinary protecting group is presented.
Compound B is a significant intermediate for the synthesis of
pharmacologically active compound (e.g. complex oligosaccharides for
biochemical, biophysical, or biological examinations). Besides, reaction
monitoring utilizing HPLC proposes more exact information than spectroscopic
methods.