(-)-Gephyrotoxin-223 was formally synthesized from chiral synthon 1 which has been CHEMOENZYMATICally synthesized in the presence of Candida Antartica lipase.  

Purpose: To describe a CHEMOENZYMATIC approach joining an enzymatic regioselective hydrolysis of peracetylatedN -acetyl-a-D-glucosamine (A) with a mild controlled acyl relocation which resulted 2-acetamido-2 deoxy-1, 3, 6-tri-O-acetyl-a-D-glucopyranose (1B).Methods: Immobilization of lipase on decaoctyl (DSEOD) and octyl-agarose (OSCL) was carried out as reported by the work of Bastidaet 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 ondecaoctylsepabeads 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 peracetylatedN -acetyl-α-D-glucosamine (A) with a mild monitored acyl movement which led to 2-acetamido-2-deoxy-1, 3, 6-tri-O-acetyl-a-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 lactosamineB containing acetyl ester as extraordinary protecting group is presented. CompoundB 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.

The enzymatic hydrolysis of meso-1, 7-diacetoxy-2,6-dimethylheptane 5, prepared from 2,6-dimethylhepta-1,6-diene 6, gave the (2S,6R)-7-acetoxy-2,6-dimethyl-1-heptanol 1, which was transformed to the (2R,6R)-2,6,10-trimethyl-1-undecanol 7. In this manner, the C14 side chain of a-Tocopherol was synthesized from 2,6-dimethylhepta-1,6-diene 6 in only 5 steps.