Kiyoshi Arai

A new dialdose dianhydride

Abstract A new dialdose dianhydride derivative was obtained from an acid hydrolyzate of the water-soluble polysaccharide of wobaku wood by successive treatment with methanolic hydrogen chloride and acetic anhydride-pyridine. This compound was determined to be the 1,2′:1′,2-dianhydride of 3,4-di- O -acetyl-β- l -rhamnopyranose and methyl 3,4-di- O -acetyl-α- d -galactopyranuronate.

Synthesis of the 1,2′:1′,2-dianhydride of 3,4-di-O-acetyl-β-lrhamnopyranose and methyl 3,4-di-O-acetyl-α-D-galactopyranuronate from 2-O-(α-d-galactopyranosyluronic acid)-l-rhamnopyranose

Abstract The title compound was synthesized from 2- O -(α- d -galactopyranosyluronic acid)- l -rhamnopyranose ( 1 ), showing that the dianhydride is a cyclization product of 1 . Formation of the dianhydride reached a maximum within 4 h, in both 2.5 and 5% methanolic hydrogen chloride at 90°.

Physicochemical studies of the water-soluble polysaccharide of Phellodendron amurense Ruprecht☆

Abstract Purified, water-soluble polysaccharide of Phellodendron amurense Ruprecht (P-WSPS) was obtained in highly homogeneous state. The partial specific volume and intrinsic viscosity were, respectively, 0.56 and 11.68 dL/g. The S value and molecular weight depended strongly on the P-WSPS concentration, but extrapolation to infinite dilution gave S w,20 0 = 10.67 × 10 −13 s −1 and M 0 = 625 × 10 3 from velocity-sedimentation and equilibrium-sedimentation experiments, respectively, results that showed the highly branched structure of P-WSPS. The molecular weight calculated from the D 0 value (1.035 × 10 −7 ) and S 0 value agreed with that from the equilibrium-sedimentation experiment to within ∼±9%, showing that the diffusion method is useful for rapid estimation of molecular weight.

Chemical structure of the water-soluble polysaccharide of Phellodendron amurense Ruprecht☆

Abstract Purified, water-soluble polysaccharide (P-WSPS) of Phellodendron amurense Ruprecht consists of residues of l -rhamnose, l -arabinose, d -galactose, and d -galacturonic acid in the ratios of 29.26:22.45:31.17:17.10 (% by weight). G.l.c.m.s. analysis of methylated-reduced P-WSPS showed that it has a very complicated and highly branched structure, and consists mainly of (1→2)-linked l -rhamnose, (1→4)-linked l -arabinose, (1→4)-linked d -galactose, and (1→3)- and (1→4)-linked d -galacturonic acid. The presence of 2- O -(α- d -galactopyranosyluronic acid)- l -rhamnopyranose, 2- O -(β- d -galactopyranosyluronic acid)- l -arabinose, 4- O -(α- d -galactopyranosyluronic acid)- l -rhamnopyranose, and 4- O -(α- d -galactopyranosyluronic acid)- d -galactopyranose in the aldobiouronic acid fraction of the hydrolyzate of P-WSPS was also shown.

Mass spectra of peracetates of some (1→2)-linked disaccharides

Abstract The mass spectra of two peracetylated disaccharides and the pentaacetate ( 1 ) of an aldobiouronic acid methyl ester, all having a (1→2)-linkage, were analyzed. The fragmentation pathway common to these compounds could be classified into four groups: ( 1 ) the aA type, which was the main pathway, ( 2 ) the abJ type, ( 3 ) the baA type, and ( 4 ) the baC type. The manner of fragmentation of peracetate 1 was similar to those of the disaccharides.

Variety of molecular species of the water-soluble polysaccharide of Phellodendron amurense Ruprecht

Abstract The molecular weight of the water-soluble polysaccharide of Phellodendron amurense Ruprecht was found to differ with the sample used. The difference is considered to be due to different degrees of degradation of the polysaccharide chains, together with oxidation of galactose to galacturonic acid residues.

Chemical ionization-mass spectra of aldobiouronic acids and dialdose dianhydrides

Abstract Chemical ionization (c.i.) mass spectra with isobutane as the reagent gas are reported for the peracetates of aldobiouronic acids and related compounds, and for peracetates and permethylated derivatives of dialdose dianhydrides. Ions (M + + 43) having relatively high intensities were detected in the spectra of disaccharides lacking the dianhydride structure. Peracetylated dialdose dianhydrides showed very weak (M + + 43) ions, and permethylated dianhydrides did not show them. The (M + + 43) ion consisted of molecular ion and acetoxyl radical (but not of the reagent gas). In the c.i. mass spectra of the usual disaccharide peracetates, (M + − 31) and (M + − 60) ions had large intensities. In contrast, c.i. mass spectra extremely similar to the corresponding e.i. mass spectra were obtained for dialdose dianhydrides.

Mass-spectral fragmentations of peracetylated dialdose dianhydrides☆

Abstract Mass spectra of peracetylated dialdose dianhydrides were measured and fragmentation pathways were discussed. Four characteristic peaks at m / e title 316, 303. 288, and 275, are effective in the identification of dialdose dianhydrides.