(1)H and (13)C spectroscopic data for 5H-[1,3]thiazolo[2,3-b]quinazolin-5-one and 12H-[1,3]benzothiazolo[2,3-b]quinazolin-12-one derivatives were fully assigned by combination of one- and two-dimensional experiments (DEPT, HMBC and HMQC). Both heterocyclic systems show similar spectroscopic properties with some remarkable differences.

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A synthetic route to prepare 4-methylumbelliferyl-b-Dglucopyranosiduronic acid (MUG) from 4-methylumbelliferyl-b-Dglucopyranoside (MUGluc) was developed. The primary hydroxyl group in MUGluc was protected by tritylation followed by acetylation of secondary hydroxyls. The triphenylmethyl group was selectively removed by treatment with iodine-methanol in benzene and the free hydroxyl was transformed into the carboxylic acid by phase-transfer oxidation with sodium hypochlorite and TEMPO as catalyst. Finally, the acetate groups were removed by reaction with barium methoxide in methanol to afford the MUG with an overall yield of 37% from the MUGluc.