Di-tert-butyl 4-[(2-tert-butoxycarbonyl)ethyl]-4-aminoheptanedicarboxnate
Di-tert-butyl 4-[(2-tert-butoxycarbonyl)ethyl]-4-aminoheptanedicarboxnate
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DOI：
10.1080/00304949609356563
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发表时间：
1996-08-01
影响因子：
1.5
通讯作者：
Weis, CD
中科院分区：
文献类型：
--
作者：
Newkome, GR;Weis, CD
许多高度支化的脂肪族树枝状或级联大分子已经“使用不同的分子构建块”（或砖）制备。特别地，结晶4-[（2-叔丁氧基羰基）乙基]-4-氨基庚烷二甲酸二叔丁酯2（"Behera胺"）由于其独特的多功能性而具有多种应用。这种树枝状砖块的吸引人的特征包括（a）sp3碳支化中心，（B）预形成的分支，（c）氨基部分的容易酰化，和（d）羧酸保护基的定量去除。然而，胺2的原始合成4不容易进行大规模制备;具体地，2的色谱纯化在时间和材料方面都是昂贵的。我们在此报告改进程序的合成硝基三酯1和随后的减少Behera的胺2。硝基三酯1通过用略多于三当量的丙烯酸叔丁酯在二甲氧基乙烷（Dm）中处理硝基甲烷来制备。在反应中产生的痕量黄色杂质容易通过重结晶除去;除去这些有色污染物避免了所需单体2的色谱纯化。i）TritonB，DME ii）T-1阮内镍，Hz. 50 - 55 "。iii）在稍高的温度下硝基三酯1氢化成氨基三酯2是已知的γ-硝基叔酯的还原产物的意外例外。所有先前已知的这种还原的实例都容易环化，得到相应的2，2 ′-二取代的吡咯烷酮。因此，在仔细控制的温度条件下使用新鲜制备的T-1阮内镍在45 - 55 ° C下进行催化氢化，提供了（约100 ° C）。90%）的纯单体2。
Many highly branched aliphatic dendritic or cascade macromolecules have been prepared'using different molecular building blocks'(or bricks). In particular, crystalline-'di-terr-butyl4-[(2-tert-butoxycarbonyl) ethyl]-4-aminoheptanedicarboxylate 2 (" Behera's amine") has found diverse applications owing to its unique versatility." Attractive features of this dendritic brick include (a) an sp3 carbon branching center,(b) preformed branches,(c) facile acylation of the amino moiety, and (d) quantitative removal of the carboxylic acid protecting groups. However, the original synthesis4 of amine 2 was not readily amenable to large scale preparations; specifically, chromatographic purification of 2 was expensive in terms of both time and materials. We herein report improved procedures for the synthesis of nitrotriester 1 and its subsequent reduction to Behera's amine 2. Nitrotriester 1 was prepared via treatment of nitromethane with slightly more than three equivalents of tert-butyl acrylate in dimethoxyethane (Dm). Trace yellow impurities produced in the reaction were easily removed by recrystallization; removal of these colored contaminants circumvents chromatographic purification of the desired monomer 2. d-- I-l (75-81%) 2 (89-938) 3 (100%) i) TritonB, DME ii) T-1 Raney Ni, Hz. 50-55". iii) AHydrogenation of the nitrotriester 1 to the aminotriester 2 at slightly elevated temperature presented a serendipitous exception to the reduction products of known tertiary, y-nitroe~ ters.~ All previously known examples of such reductions readily cyclize to afford the corresponding 2, 2'-disubstituted pyrrolidones. Therefore, catalytic hydrogenation conducted under carefully controlled temperature conditions using freshly prepared T-1 Raney Nickel at 45-55'provided (ca. 90%) the pure monomer 2.