Concise preparation of biologically active chitooligosaccharides
Chitooligosaccharides (COSs) have demonstrated a diverse array of biological activities. Here we report a concise preparation method for tetra-N-acetyl-chitotetraose and penta-N-acetyl-chitopentaose. The FACE analysis showed that the partially N-acetylated COS mixture mainly contained glucosamine (GlcN) and some oligomers [(GlcN)n, n = 2-7]. The N-acetyl-D-glucosamine (GlcNAc) and peracetylated COSs [(GlcNAc)n, n = 2-7] were synthesised by treating the partially N-acetylated COS mixture with Ac2O-NaOAc. The peracetylated chitotetraose and chitopentaose were obtained by isolation of peracetylated COS mixture. NaOMe in dry MeOH was used for the deacetylation of peracetylated chitotetraose and chitopentaose, to give the tetra-N-acetyl- chitotetraose and penta-N-acetyl-chitopentaose, respectively.
