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求翻译一段英文文献，呼叫老虫子~~
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2.1. Synthesis of hydrophilic Fischer carbene complexes To prepare a water-soluble carbene complex, it was thought that hydrophobicity of part A of the complex can perhaps be compensated by a strong hydrophilic group like an ionic group, or OEG/PEG groups in part B or part C (Fig. 1). Our initial attempt was to incorporate an ionic group NMeþ 3 . We, therefore, synthesized carbene complex 3 from m-bromo-N,N-dimethylaniline 2 that was obtained from m-bromoaniline 1 (Scheme 1). The amino group was placed at the m-position rather than o- or p- so that electron density from nitrogen does not get delocalized towards the M@C bond and makes quarternization a difficult proposition. Aromatic ring, although a hydrophobic fragment, was chosen to attach directly with carbene part, since it makes synthesis easier and the color change from red to yellow would facilitate monitoring of carbene aminolysis. The carbene complex 3 was fully characterized by spectroscopic methods. The IR spectrum showed bands at 1915 and 2065 cm1, which are characteristic of a Fischer carbene complex. In the 13C NMR spectrum, the peak at 321.0 ppm was assigned to the carbene carbon, typical of a Fischer carbene complex. Our initial attempts to quaternize carbene complex 3 with MeI in a common organic solvent like ether, benzene, or pet ether did not meet with success. Therefore, we dissolved the complex in large excess of MeI and stirred the mixture at room temperature. After 48 h, an orange precipitate was deposited (Scheme 1) which was identified as the quaternized salt 4 by 1H and 13C NMR and IR spectroscopy. In the proton NMR spectrum, position of N-methyl group shifted downfield from 3.03 to 4.02 ppm after quaternization. The corresponding 13C NMR signal of the N-methyl carbon was similarly deshielded (from 40.4 to 57.9 ppm). The IR spectrum showed characteristic absorption at 1942 and 2072 cm1, typical of a carbene complex. However, solubility of complex 4 in water is poor (<0.05 mg/ml), making the complex practically unsuitable for reaction in aqueous medium. Discouraged, we decided to explore introduction of ethylene glycol units of different chain lengths (oligo/polyethylene glycol) to impart hydrophilicity to such carbene complexes. We started with a readily available and relatively inexpensive triethylene glycol derivative. The carbene complex 6a was prepared from the corresponding salt 5a [14] (Scheme 2) in the usual manner using acetyl chloride in dichloromethane at 40 C to generate the unstable acetoxy carbene, which was allowed to react with monomethoxytriethylene glycol to furnish the desired product 6a as a dark red liquid. In spite of the hydrophilicity of triethylene glycol part the complex was not significantly water-soluble. |
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3楼2013-04-29 20:50:41
【答案】应助回帖
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王小盼子: 金币+15, 翻译EPI+1, ★★★很有帮助 2013-05-08 16:24:50
王小盼子: 金币+15, 翻译EPI+1, ★★★很有帮助 2013-05-08 16:24:50
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2.1. Synthesis of hydrophilic Fischer carbene complexes 合成亲水性的费舍尔碳烯复合物To prepare a water-soluble carbene complex, 为了制备水溶性的碳烯复合物 it was thought that hydrophobicity of part A of the complexcan perhaps be compensated by a strong hydrophilic group 可以认为疏水性的复合物A部分（基团）可以被很强的的亲水性基团补偿 like an ionic group, or OEG/PEG groups in part B or part C (Fig. 1). 比如说在复合物的B部分或者C部分增加离子基团，或者OEG/PEGOur initial attempt was to incorporate an ionic group NMeþ 我们最初的想法是加入一个离子基团NMeþ（这是你用到的离子基团吗）3 . We, therefore, synthesized carbene complex 3 from m-bromo-N,N-dimethylaniline 2 that was obtained from m-bromoaniline 1 (Scheme 1). 我们用（m-bromo-N,N-dimethylaniline 2） m-溴-N，N-二甲基苯胺2合成碳烯复合物3. 2是由m-溴苯胺制取。 The amino group was placed at the m-position rather than o- or p- m-位的氨基被取代而不是o-位或者p-位 so that electron density from nitrogen does not get delocalized towards the M@C bond and makes quarternization a difficult proposition. 这样做的目的使氮原子电子不向M@C键离域，防止增加季胺化的难度 Aromatic ring, although a hydrophobic fragment, was chosen to attach directly with carbene part, since it makes synthesis easier and the colorchange from red to yellow would facilitate monitoring of carbene aminolysis. 芳环虽然是疏水性的片段，还是要直接加在碳烯复合物上，因为芳环使反应更加容易并且会发生由红色变为黄色，这有利于观察氨解的反应程度。 The carbene complex 3 was fully characterized by spectroscopic methods. The IR spectrumshowed bands at 1915 and 2065 cm1, which are characteristic of a Fischer carbene complex. In the 13C NMR spectrum, the peak at 321.0 ppm was assigned to the carbene carbon, typical of a Fischer carbene complex. 这个碳烯复合物可以很好的用光谱法检测。红外光谱显示1915 2065峰，是费舍尔碳烯复合物的标志峰。在13C的核磁谱中，321.0ppm是费舍尔碳烯复合物的典型标志。Our initial attempts to quaternize carbene complex 3 with MeI in a common organic solvent like ether, benzene, or pet ether did not meet with success. 我们一开始的目的是用普通的有机溶剂如乙醚，苯，石油醚等溶解带有MeI的季胺化碳烯复合物，但是这些溶剂都不合适。 Therefore, we dissolved the complex in large excess of MeI and stirred the mixture at room temperature. 因此，我们用过量的MeI溶解复合物，在室温下搅拌。 After 48 h, an orange precipitate was deposited (Scheme 1) which was identified as the quaternized salt 4 by 1H and 13C NMR and IR spectroscopy. 48小时后，一个橘黄色的沉淀物出现，经1H和13C核磁测定就是季胺化盐4. In the proton NMR spectrum, position of N-methyl group shifted downfield from 3.03 to 4.02 ppm after quaternization. The corresponding 13C NMR signal of the N-methyl carbon was similarly deshielded (from 40.4 to 57.9 ppm). 在质子核磁谱中，季胺化后N-甲基位的峰值从3.03上移到4.02ppm，相应的，13C谱中N_甲基碳有相似的情况（从40.4上移到57.9ppm） The IR spectrum showed characteristic absorption at 1942 and 2072 cm1, typical of a carbene complex. 红外谱显示特征吸收峰是1942和2072，典型的碳烯复合物吸收峰。However, solubility of complex 4 in water is poor(<0.05 mg/ml), making the complex practically unsuitablefor reaction in aqueous medium. 然而，复合物4的水溶性很差，不适合在水相反应。 Discouraged, we decided to explore introduction of ethylene glycol units of different chain lengths (oligo/polyethylene glycol) to impart hydrophilicity to such carbene complexes. 失望的，我们决定探索引入不同碳链长度乙二醇单元（oligo 一种不受消化酶分解的糖 聚乙二醇）给予这个碳烯复合物水溶性。 We started with a readily available and relatively inexpensive triethylene glycol derivative. 我们开始用一种准备好的可行的相关的不贵的三乙烯乙二醇的衍生物。 The carbene complex 6a was prepared from the corresponding salt 5a [14] (Scheme 2) in the usual manner using acetyl chloride in dichloromethane at 40 C to generate the unstable acetoxy carbene, 碳烯复合物6a是用相应的盐5a（14）用一般的反应方法。即二氯甲烷溶解乙酰氯40℃使形成不稳定的乙酰氧碳烯。 which was allowed to react with monomethoxytriethylene glycol to furnish the desiredproduct 6a as a dark red liquid. 乙酰氧碳烯可以和一甲基三乙烯乙二醇反应得到目标产品6a，一个暗红色液体。 In spite of the hydrophilicity of triethylene glycol part the complex was not significantly water-soluble. 尽管有三乙烯乙二醇基团，这个复合物不是明显的水溶的。 |
2楼2013-04-27 13:52:06
