| Sumario: | Various tetra-O-acetyl-D-hexopyranoses were known to undergo acetyl migration upon methylation with Purdie's reagents; thus, 1,2,3,4-tetra-O-acetyl-β-D-glucopyranose, 1,2,3,6-tetra-O-acetyl-β-D-glucopyranose, and 1,3,4,6-tetra-O-acetyl-β-D-glucopyranose and its α anomer are converted into methyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside when methylated with methyl iodide and silver oxide. It is now found that, when each of the above compounds is treated with diazomethane-boron trifluoride etherate, the methylated product is produced in high yield, with the methyl ether group in the expected position. Under the same conditions, 1,3,4,6-tetra-O-α-D-galactopyranose is converted into the 2-methyl ether without the acetyl migration which had been observed when the tetra-O-acetyl-D-galactopyranose was methylated with Purdie's reagents. The tetra-O-acetyl-O-methyl-D-hexopyranoses were then transformed by deacetylation into the following mono-O-methylhexoses: 2-O-methyl-β-D-glucose, 4-O-methyl-D-glucose, 6-O-methyl-α-D-glucose, and 2-O-methyl-β-D-galactose. © 1966.
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