Development and Optimization of a New Chemoenzymatic Approach for the Synthesis of Peracetylated Lactosamine (Intermediate for the Synthesis of Pharmacologically Active Compounds) Monitored by RP HPLC Method

Purpose: To describe a chemoenzymatic approach joining an enzymatic regioselective hydrolysis of peracetylated NacetylαDglucosamine (A) with a mild controlled acyl relocation which resulted 2acetamido2 deoxy1,3,6triOacetylαDglucopyranose (1B). Methods: Immobilization of lipase on decaoctyl (DSEOD) and octylagarose (OSCL) was carried out as reported by the work of Bastida et al. The newly developed RPHPLC 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 rugosalipase immobilized ondecaoctylsepabeads was the best catalyst in terms of activity and regionselectivity in the hydrolysis of substrate (A), delivering the deacetylation at C6 position (98% general yield). Also, a reversedphase highperformance liquidchromatographic (RPHPLC) method for controlling the regionselective hydrolysis of peracetylated NacetylαDglucosamine (A) with a mild monitored acyl movement which led to 2acetamido2deoxy1,3,6triOacetylαDglucopyranose (1B) has additionally been developed. The developed RPHPLC 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.