The acetylation of apiitol in the determination of apiose

Article abstract of DOI:10.1016/0008-6215(90)84092-9

The complete acetylation of apiitol required 9 h when acetic anhydride at 120 deg C was used and sodium acetate was the catalyst.Both apiitol pentaacetate and apiitol tetraacetate were detected before acetylation was complete.When the reaction was done in dimethyl sulfoxide, with 1-methylimidazole as the catalyst, a third compound was observed, and identified as 1,2,4-tri-O-acetyl-3-C-(acetoxymethyl)-3-O-(methylthiomethyl)-D-glycero-tetritol <3-O-(methylthiomethyl)apiitol tetraacetate> by gas-liquid chromatography and mass spectrometry.In N,N-dimethylformamide, with1-methylimidazole as the catalyst, the acetylation of apiitol was essentially complete in 4 h at 85 deg C, and the formation of methylthiomethyl ether was avoided.A method for preparing alditol acetates using 1-methylimidazole as the catalyst, and suitable for samples containing apiose as well as ordinary sugars, is described.The separation of apiitol pentaacetate from xylitol pentaacetate by gas-liquid chromatography proved difficult.However, a virtually complete separation of the peracetates of apiitol and xylitol as well as complete separation of those of rhamnitol, fucitol, arabinitol, mannitol, galactitol, glucitol, and myo-inositol, plus apiitol tetraacetate and 3-(O-methylthiomethyl)apiitol tetraacetate, was accomplished with a 30 m x 0.53 mm (i.d.) SP-2380 column in 49 min, and on a 30 m x 0.75 mm (i.d.) SP-2330 column in 82 min.A complete separation of apiitol and xylitol pentaacetates as well as four other alditol peracetates was obtained with a 60 m DB-1 column in 15.2 min, however this column did not resolve the acetates of fucitol and arabinitol.A variety of other columns and column conditions were ineffective.