Conversion of glucosamine to galactosamine and allosamine derivatives: control of inversions of stereochemistry at C-3 and C-4.
The reactions of sodium benzoate with a series of trimesylates derived from glucosamine have been examined in an attempt to gain facile access to galactosamine analogues. Trimesylate 17, in which the amino group was protected as a phthalimide, underwent double displacement at positions 4 and 6 to give the dibenzoate 18 with the desired galactosamine configuration. In contrast, trimesylates 21 and 27, in which the amino groups were protected as acetamides, unexpectedly underwent double displacement at positions 3 and 6, giving products 22 and 28, respectively, with allosamine configurations.
McGeary
R P
RP
School of Pharmacy, The University of Queensland, Brisbane, QLD 4072, Australia.
Wright
K
K
Toth
I
I
D005688:Galactosamine / Q000138:chemical synthesis*; D005944:Glucosamine / Q000031:analogs & derivatives / Q000737:chemistry*; D007202:Indicators and Reagents; D008968:Molecular Conformation; D013237:Stereoisomerism
D007202:Indicators and Reagents; C433386:allosamine; D005688:Galactosamine; D005944:Glucosamine