| Research Abstract |
The research aimed to synthesize and apply novel carbohydrate polymers for optical resolution system, and the author reported that 1) the ring-opening polymerization of 1,6-anhydro sugar and 2) the optical resolution of (l→6)-α-D-hexopyranan phenylcarbamate derivatives as chiral stationary phase in HPLC.
1) For the convenient synthesis of (1→6)-α-D-glucopyranan, the ring-opening polymerization of 2,3,4-tri-O-allyl-β-D-glucopyranose (1) have been carried out using BF_3・OEt_2. For the condition of [BF_3・OEt_2]/[1] = 0.05 at 0℃ for 140 h, the yield and M_w of the obtained polymer were 84.0 % and 44,300 (DP_n = 157), respectively. The polymer structure was (1→6)-α-linked 2,3,4-tri-O-allyl-D-glucopyranose, i.e., (1→6)-2,3,4-tri-O-allyl-D-glucopyranan (2), The resulting polymer 2 was isomerized using triphenylphosphinechlororhodium as a catalyst in toluene/ethanol/water to yield (1→6)-2,3,4-tri-O-propenyl-α-D-glucopyranan (3). Then the deprotection of the propenyl ether linkage in the obtaine
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d polymer 3 was performed using HCl in acetone to give (1→6)-α-D-glucopyranan.
2) Synthetic polysaccharides, (1→6)-α-D-glucopyranan (3a) and (1→6)-α-D-mannopyranan (3b), were prepared by the cationic ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-aIlyl-β-D-glucopyranose (1a) and 1,6-anhydro-2,3,4-tri-O-allyl-β-D-mannopyranose (1b), followed by the cleavage of the allyl ether linkage of 2,3,4-tri-O-allyl-(1→6)-α-D-glucopyranan (2a) and 2,3,4-tri-O-allyl-(1→6)-α-D-mannopyranan (2b), respectively. 2,3,4-Tris-O-(3,5-dimethylphenylcarbamoyl)- and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1→6)-α-D-glucopyranan (CSP-1 and CSP-2, respectively) and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1→6)-α-D- mannopyranan (CSP-3 and CSP-4, respectively) were prepared by the reaction of 3 with the corresponding 3,5-disubstituted phenylisocyanates, and the chiral recognition abilities of CSP-1〜4 as chiral stationary phases (CSPs) in high-performance liquid chromatography (HPLC) were evaluated. The racemic compounds such as /trans-cyclopropanedicarboxylic acid dianilide (9), 1,2,2,2-tetraphenylethanol (10), flavanone (11), Troger's base (12), benzoin (13), and cobalt(III) tris(acetylacetonate) (14) were efficiently resolved using CSP-1〜4. For comparison among CSPs, the chirai recognition property of the (1→6)-α-D-glucopyranan CSPs was different from that of the (1→6)-α-D-maannopyranan CSPs, and CSP-4 exhibited the highest chiral recognition ability among the CSPs. The resolution factors of 12 and 14 were 0.42 and 0.56 for CSP-1, 0.32 and 2.16 for CSP-2, 1.80 and 0.84 for CSP-3, and 2.31 and 8.26 for CSP-4, respectively. Less
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