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求翻譯一段英文文獻(xiàn)，呼叫老蟲子~~
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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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王小盼子: 金幣+15, 翻譯EPI+1, ★★★很有幫助 2013-05-08 16:24:50
王小盼子: 金幣+15, 翻譯EPI+1, ★★★很有幫助 2013-05-08 16:24:50
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2.1. Synthesis of hydrophilic Fischer carbene complexes 合成親水性的費(fèi)舍爾碳烯復(fù)合物To prepare a water-soluble carbene complex, 為了制備水溶性的碳烯復(fù)合物 it was thought that hydrophobicity of part A of the complexcan perhaps be compensated by a strong hydrophilic group 可以認(rèn)為疏水性的復(fù)合物A部分（基團(tuán)）可以被很強(qiáng)的的親水性基團(tuán)補(bǔ)償 like an ionic group, or OEG/PEG groups in part B or part C (Fig. 1). 比如說在復(fù)合物的B部分或者C部分增加離子基團(tuán)，或者OEG/PEGOur initial attempt was to incorporate an ionic group NMeþ 我們最初的想法是加入一個(gè)離子基團(tuán)NMeþ（這是你用到的離子基團(tuán)嗎）3 . We, therefore, synthesized carbene complex 3 from m-bromo-N,N-dimethylaniline 2 that was obtained from m-bromoaniline 1 (Scheme 1). 我們用（m-bromo-N,N-dimethylaniline 2） m-溴-N，N-二甲基苯胺2合成碳烯復(fù)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. 這樣做的目的使氮原子電子不向M@C鍵離域，防止增加季胺化的難度 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. 芳環(huán)雖然是疏水性的片段，還是要直接加在碳烯復(fù)合物上，因?yàn)榉辑h(huán)使反應(yīng)更加容易并且會(huì)發(fā)生由紅色變?yōu)辄S色，這有利于觀察氨解的反應(yīng)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. 這個(gè)碳烯復(fù)合物可以很好的用光譜法檢測。紅外光譜顯示1915 2065峰，是費(fèi)舍爾碳烯復(fù)合物的標(biāo)志峰。在13C的核磁譜中，321.0ppm是費(fèi)舍爾碳烯復(fù)合物的典型標(biāo)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. 我們一開始的目的是用普通的有機(jī)溶劑如乙醚，苯，石油醚等溶解帶有MeI的季胺化碳烯復(fù)合物，但是這些溶劑都不合適。 Therefore, we dissolved the complex in large excess of MeI and stirred the mixture at room temperature. 因此，我們用過量的MeI溶解復(fù)合物，在室溫下攪拌。 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小時(shí)后，一個(gè)橘黃色的沉淀物出現(xiàn)，經(jīng)1H和13C核磁測定就是季胺化鹽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). 在質(zhì)子核磁譜中，季胺化后N-甲基位的峰值從3.03上移到4.02ppm，相應(yīng)的，13C譜中N_甲基碳有相似的情況（從40.4上移到57.9ppm） The IR spectrum showed characteristic absorption at 1942 and 2072 cm1, typical of a carbene complex. 紅外譜顯示特征吸收峰是1942和2072，典型的碳烯復(fù)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，復(fù)合物4的水溶性很差，不適合在水相反應(yīng)。 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，我們決定探索引入不同碳鏈長度乙二醇單元（oligo 一種不受消化酶分解的糖 聚乙二醇）給予這個(gè)碳烯復(fù)合物水溶性。 We started with a readily available and relatively inexpensive triethylene glycol derivative. 我們開始用一種準(zhǔn)備好的可行的相關(guān)的不貴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, 碳烯復(fù)合物6a是用相應(yīng)的鹽5a（14）用一般的反應(yīng)方法。即二氯甲烷溶解乙酰氯40℃使形成不穩(wěn)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應(yīng)得到目標(biāo)產(chǎn)品6a，一個(gè)暗紅色液體。 In spite of the hydrophilicity of triethylene glycol part the complex was not significantly water-soluble. 盡管有三乙烯乙二醇基團(tuán)，這個(gè)復(fù)合物不是明顯的水溶的。 |
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