- Formal Synthesis of Anticoagulant Drug Fondaparinux Sodium
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The practical formal synthesis of the anticoagulant drug fondaparinux sodium 1 was accomplished using an optimized modular synthetic strategy. The important pentasaccharide 2, a precursor for the synthesis of fondaparinux sodium, was synthesized on a 10 g scale in 14 collective steps with 3.5% overall yield from well-functionalized monosaccharide building blocks. The strategy involved a convergent [3 + 2] coupling approach, with excellent stereoselectivity in every step of glycosylation from the monosaccharide building blocks. Efficient routes to the syntheses of these fully functionalized building blocks were developed, minimizing oligosaccharide stage functional-group modifications. The syntheses of all building blocks avoided rigorous reaction conditions and the use of expensive reagents. In addition, common intermediates and a series of one-pot reactions were employed to enhance synthetic efficiency, improving the yield considerably. In the monosaccharide-to-oligosaccharide assembly reactions, cheaper activators (e.g., NIS/TfOH, TESOTf, and TfOH) were used to facilitate highly efficient glycosylations. Furthermore, crystallization of several monosaccharide and oligosaccharide intermediates significantly simplified purification procedures, which would be greatly beneficial to the scalable synthesis of fondaparinux sodium.
- Dai, Xiang,Liu, Wentao,Zhou, Qilong,Cheng, Chunwei,Yang, Chao,Wang, Shuqing,Zhang, Min,Tang, Pei,Song, Hao,Zhang, Dan,Qin, Yong
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p. 162 - 184
(2016/01/15)
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- SYNTHESIS OF HEPARIN FRAGMENTS. A CHEMICAL SYNTHESIS OF THE TRISACCHARIDE O-(2-DEOXY-2-SULFAMIDO-3,6-DI-O-SULFO-α-D-GLUCOPYRANOSYL)-(1->4)-O-(2-O-SULFO-α-L-IDOPYRANOSYL-URONIC ACID)-(1->4)-2-DEOXY-2-SULFAMIDO-6-O-SULFO-D-GLUCOPYRANOSE HEPTASODIUM SALT
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Known 3-O-benzyl-1,2-O-isopropylidene-α-D-glucofuranose was first converted into methyl 3-O-benzyl-1,2-O-isopropylidene-β-L-idofuranuronate.Acid hydrolysis, followed by acetylation and treatment with titanium tetrabromide, gave methyl (2,4-di-O-acetyl-3-O-benzyl-α-L-idopyranosyl bromide)uronate, which was immediately transformed into methyl 4-O-acetyl-3-O-benzyl-β-L-idopyranuronate 1,2-(tert-butyl orthoacetate).A two-step replacement of the 4-O-acetyl by a 4-O-chloroacetyl group gave the key derivative, crystalline methyl 3-O-benzyl-4-O-chloroacetyl-β-L-idopyranuronate 1,2-(tert-butyl orthoacetate).Condensation of this orthoester with an excess of crystalline benzyl 6-O-acetyl-3-O-benzyl-2-(benzyloxycarbonyl)amino-2-deoxy-α-D-glucopyranoside in chlorobenzene in the presence of 2,6-dimethylpyridinium perchlorate gave crystalline benzyl 6-O-acetyl-3-O-benzyl-2-(benzyloxycarbonyl)amino-2-deoxy-4-O-(methyl 2-O-acetyl-3-O-benzyl-4-O-chloroacetyl-α-L-idopyranosyluronate)-α-D-glucopyranoside in 40 percent yield.O-Demonochloroacetylation, followed by condensation with known 3,6-di-O-acetyl-2-azido-4-O-benzyl-2-deoxy-α-D-glucopyranosyl bromide in dichloromethane in the presence of 2,4,6-trimethylpyridine, silver triflate, and molecular sieve provided benzyl O-(3,6-di-O-acetyl-2-azido-4-O-benzyl-2-deoxy-α-D-glucopyranosyl)-(1->4)-O-(methyl 2-O-acetyl-3-O-benzyl-α-L-idopyranosyluronate)-(1->4)-6-O-acetyl-3-O-benzyl-2-(benzyloxycarbonyl)amino-2-deoxy-α-D-glucopyranoside in 88 percent yield.O-Deacetylation with sodium hydroxide, followed successively by O-sulfation in N,N-dimethylformamide in the presence of sulfur trioxide-trimethylamine complex, catalytic hydrogenolysis, and N-sulfation in water with the same sulfating agent, gave the heptasodium salt of O-(2-deoxy-2-sulfamido-3,6-di-O-sulfo-α-D-glucopyranosyl)-(1->4)-O-(2-O-sulfo-α-L-idopyranosyluronic acid)-(1->4)-2-deoxy-2-sulfamido-6-O-sulfo-D-glucopyranose.This trisaccharide, which is a fragment of the minimal antithrombin III-binding region in heparin, neither binds to antithrombin III nor induces anti-Xa activity.
- Jacquinet, Jean-Claude,Petitou, Maurice,Duchaussoy, Philippe,Lederman, Isidore,Choay, Jean,et al.
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p. 221 - 242
(2007/10/02)
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