Convenient synthesis of poly(γ-benzyl-L-glutamate) from activated urethane derivatives of γ-benzyl-L-glutamate
Convenient synthesis of poly(γ-benzyl-L-glutamate) from activated urethane derivatives of γ-benzyl-L-glutamate
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DOI：
10.1002/pola.22595
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发表时间：
2008-04-15
影响因子：
--
通讯作者：
Endo, Takeshi
中科院分区：
文献类型：
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作者：
Kamei, Yasutaka;Nagai, Atsushi;Endo, Takeshi
合成了一系列γ-苄基-L-谷氨酸的活化氨基甲酸酯型衍生物，并研究了它们作为多肽合成单体的潜力。本工作的重点衍生物是一系列N-芳氧基羰基-γ-苄基-L-谷氨酸1，其中芳基为苯基、4-氯苯基和4-硝基苯基。这些聚氨酯1在极性溶剂如二甲亚砜、N,N-二甲基甲酰胺(DMF)和N,N-二甲基乙酰胺(DMAc)中具有反应性，并在温和条件下有效转化为聚(γ-苄基-L-谷氨酸)(聚(BLG))； 60℃下不添加任何催化剂。在这三种氨基甲酸酯中，具有4-硝基苯氧基羰基1e的氨基甲酸酯是最有效地产生聚(BLG)的，正如硝基苯氧基羰基的高度缺电子性质所预期的那样。另一方面，尽管苯氧基羰基本质上亲电性较低，但具有苯氧基羰基的氨基甲酸酯1a也被有效地转化为聚(BLG)。此外，1a反应成功形成poly(BLG)有利于其稀释浓度(0.1 M)远高于1c的最佳初始浓度2.0 M。原位反应的 H-1 NMR 光谱分析表明，从 1 到聚（BLG）的主要途径涉及 1 的分子内环化成相应的 N-羧酸酐，释放苯酚及其连续的开环聚合，释放二氧化碳。 (c) 2008 年 Wiley 期刊公司。
A series of activated urethane-type derivatives of gamma-benzyl-L-glutamate were synthesized, and their potential as monomers for polypeptide synthesis was investigated. The derivatives of the focus of this work were a series of N-aryloxycarbonyl-gamma-benzyl-L-glutamate 1, of which aryl groups were phenyl, 4-chlorophenyl, and 4-nitrophenyl. These urethanes 1 were reactive in polar solvents such as dimethylsulfoxide, N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMAc), and were efficiently converted into poly(gamma-benzyl-L-glutamate) (poly(BLG)) under mild conditions; at 60 degrees C without addition of any catalyst. Among the three urethanes, that having 4-nitrophenoxycarbonyl group le was the most reactive to give poly(BLG) efficiently, as was expected from the highly electron deficient nature of the nitrophenoxycarbonyl group. On the other hand, the urethane la having phenoxycarbonyl group was also efficiently converted into poly(BLG), in spite of the intrinsically less electrophilicity of the phenoxycarbonyl group. In addition, the successful formation of poly(BLG) by the reaction of 1a favored its diluted concentration (0.1 M) much more than 2.0 M, the optimum initial concentration for 1c. H-1 NMR spectroscopic analyses of the reactions in situ revealed that the predominant pathway from 1 to poly(BLG) involved the intramolecular cyclization of 1 into the corresponding N-carboxyanhydride, with release of phenol and its successive ring-opening polymerization with release of carbon dioxide. (c) 2008 Wiley Periodicals, Inc.