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大家最好么全部翻译，如果实在不行，可以少翻译几段。金币照给不误。 The failure of a similar addition reaction of hydrogen sulfide to the double bond of Ⅱin benzene may be explained by the very low solubility of Ⅱin benzene (0.1% in refluxing benzene). Ⅱ would precipitate as fast as it was formed in benzene and thus could not react further with hydrogen sulfide; however, since Ⅱ is soluble to a limited extent in benzene, a small amount of Ⅲ would be expected to be found if the reaction was carried out with a large excess of benzene over a long period. Small amounts of Ⅲ as well as Ⅵ were identified in the infrared spectrum of the product obtained from a reaction carried out under these conditions. Mechanisms involving the formation of thioacetic acid or ethanethiol mere eliminated since no trace of these materials could be found in the reaction mixtures from Ⅰor Ⅱand hydrogen sulfide in the presence of ethyl alcohol. Simple hydrolysis with water was also ruled out since Ⅱ could be recrystallized without hydrolysis from hot water; however, there is some question concerning the stability of Ⅱin a mixture of ethyl alcohol and water. In one experiment, Ⅱmas decomposed and no identifiable products were obtained after Ⅱ was stirred overnight in a mixture of alcohol and mater with a catalytic amount of triethylamine. A similar experiment showed that Ⅱwas stable in ethyl alcohol alone. Another mechanism, involving first the alcoholysis ofⅠor Ⅱ in the presence of hydrogen sulfide as catalyst, was considered. It was demonstrated that Ⅴ and trace quantities of ethyl acetate were obtained from triethyl orthoacetate and hydrogen sulfide; thus all the observed by-products from the reaction of hydrogen sulfide and ethyl alcohol withⅠorⅡcould be accounted for. However, Ⅰreacted with hydrogen sulfide in dimethylformamide solution to form dithiomaloiiamide (Ⅵ) ethyl thionoacetate (Ⅴ), and ethyl acetate. hlcohol, therefore, is not a necessary reactant in the cleavage, making the alcoholysis step unnecessary in explaining the mechanism for the formation of Ⅲ from Ⅰin ethyl alcohol. Other reactions of Ⅱwere studied and several compounds of this type were prepared and characterized. It was found that the alkoxy group was easily removed by mild hydrolysis. When Ⅱ was dissolved at room temperature with 4 to 5% sodium hydroxide solution and then cold, dilute (10%) hydrochloric acid solution was added, 2-cyano-3- hydroxythiocrotonamide (Ⅸ) was formed. This same compound was also prepared by simply heating Ⅱwith 10% hydrochloric acid solution at steam bath temperatures for approximately ten minutes. These reactions were generally applicable to 2-cyano-3-alkoxy-2-alkenthioamides. An attempt to prepare the mercapto derivative by replacing the 4% sodium hydroxide solution with dilute sodium hydrosulfide gave a product which had ai1 infrared spectrum consistent with the proposed structure Ⅺ. The replacement of the ethoxy group probably results from a 1,4-attack of the sodium hydroxide or hydrosulfide on the conjugated system involving the nitrile or thioamide group and the carboncarbon double bond followed by loss of sodium alkoxide. The mercapto derivative Ⅺ was less stable than the hydroxy derivative Ⅸ and slowly decomposed during the analysis and on standing. The products of the decomposition were not identified. The hydroxy and mercapto derivatives (Ⅸ,Ⅹ, and Ⅺ) were acidic in aqueous solution. The hydroxy derivative Ⅸ was titrated nith 0.5 N base and a neutralization equivalent of 146 (theor. 142) was obtained. It wab stable to further attack with hydrogen sulfide in ethyl alcohol even though it was quite soluble in the alcohol; therefore, the hydroxy derivativeⅨ was ruled out as a possible intermediate in the formation of Ⅲ from the reaction of hydrogen sulfide and ethyl alcohol with Ⅰor Ⅱ. Attempts to form the corresponding hydroxy derivative from the reaction of Ⅰwith dilute base followed by addition of acid failed to yield the expected product. NMR studies did not verify the presence of the hydroxy proton in Ⅸ; however, infrared studies of deuterated Ⅸ confirmed the presence of the hydroxy group by an observed shift on deuteration from the normal absorption for v(OH) at 3.13μ to 4.22 ν for ν(OD). The hydroxy bending vibration δ(OH) was observed at 7.0 μ. The presence of an isomeric ketonic structure was ruled out since there was no carbonyl absorption observed in the infrared spectrum. Also, Ⅸ failed to form a 2,4-dinitrophenylhydrazine derivative in either alcoholic or aqueous solution. The presence of an isomeric epoxy structure was ruled out since an oxirane analysis of Ⅸ was negative. The amide nitrogen of Ⅸwas also deuterated and the observed shifts to the longer wavelengths as a result of deuteration were from 2.97 μ [νa- (NH)] and 3.03 μ [νs(ND)] to 3.97 μ[νa (ND)] and 4.10 μ[νs(ND)]. There was also spectral evidence for considerable contribution from tautomeric structures Ⅻ and ⅩⅢ. The enol v(SH) absorption band at 3.8 μvas shifted to 5.5 μ[ν(SD)] in the deuterated compound. A solid S-methyl derivative (methyl 2-cyano-3- hydroxythiocrotonimidate) of the enol structure of Ⅳ was obtained by treating Ⅱwith methyl iodide in 4% sodium hydroxide solution. The ethyl group of Ⅱ was lost during this alkylation reaction. Upon mild oxidation of Ⅸwith iodine in potassium iodide, a disulfide, which was characterized as 3,3'-dithiobis [2- (l-hydroxyethylidene)-3-imino propionitrile](ⅩⅣ), was formed. It was surprising to find that if Ⅱ was mildly oxidized in the same manner with iodine in potassium iodide the ethyl group was lost and the same product was formed. The absence of hydrogen iodide salt formation was demonstrated by a negative halogen analysis. The stability of ⅩⅣ was somewhat surprising since simpler disulfides of this type are usually unstable; for example, 1,l'-dithiodiformamidine has not been obtained except in the form of a salt with hydrogen halides.[7] Recently 1,1 '-dithiobis-[N-phenylformamidineldihydrobromide dihydrate R as prepared from phenylthiourea.[8] It is also known that thioacetamide reacts with iodine in water to give oxidation products such as ammonium iodide, hydrogen iodide, and sulfur and that no disulfide is formed.[9] The additional resonance possibilities provided by the unsaturated, negatively substituted disulfide ⅩⅣ probably accounts for its stability as compared with the marked unstable nature of the simpler members of this class of compounds. Reaction ofⅡwith dimethylamine was found to yield 2-cyano-3-dimethy- lamino- thiocrotonamide, in which the alkoxy group of Ⅱ is replaced with the dialkylamino group. The ethoxy group mas also replaced by anhydrous ammonia to form S-amino-2- cyanothiocrotonamide. These alkoxy replacement reactions are consistent with reported reactions of diethyl ethoxymethylenemalonate to form the aminomethylenemalonic ester.[10] Other derivatives of substituted methylenemalononitriles prepared were 2-cyano-3-phenyl- thioacrylamide, 2-cyano-3-(2-thienyl)thioacrylamide, and 2-cyano-3-(2-furyl) thioacrylamide. Acknowledgment.—The author is indebted to Dr. H. W. Coover and Dr. N. H. Shearer for helpful discussions and suggestions throughout this study. Thanks are also due Mr. M. V. Otis for infrared analyses, Dr. V. W. Goodlett for NMR studies, Mr. C. L.Harrison for gas chromatographic analyses, and Mr. J. S. Lewis for mass spectrometric analyses. [ Last edited by 应用化学 on 2009-5-17 at 23:51 ] |
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7楼2009-05-18 12:38:07
★ ★ ★ ★ ★
应用化学(金币+5,VIP+0):先给五个吧，以后再给，谢谢哦 5-18 11:27
zap65535(金币-3,VIP+0):强制发赏 12-23 19:13
zap65535(金币+3,VIP+0):失误 12-23 19:13
应用化学(金币+5,VIP+0):先给五个吧，以后再给，谢谢哦 5-18 11:27
zap65535(金币-3,VIP+0):强制发赏 12-23 19:13
zap65535(金币+3,VIP+0):失误 12-23 19:13
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第一段： 在苯中，硫化氢与双II类似的叠加反应的失败可能是由于II在苯中的溶解度太低，其在冷的苯中只有0.1%。II一旦在苯溶液中形成即沉淀下去，这样便无法与硫化氢进一步反应了；但是，考虑到II在苯中有限的溶解性，如果用过量的苯溶解掉II，然后经过很长的时间后，少量的III可能会生成。在上述条件的反应下获得的产物的红外光谱中发现了少量的III和VI。 |
2楼2009-05-18 10:44:26
3楼2009-05-18 10:52:35
★ ★ ★ ★ ★
应用化学(金币+5,VIP+0):很感谢，再翻译的话金币还有哦 5-18 11:29
应用化学(金币+5,VIP+0):很感谢，再翻译的话金币还有哦 5-18 11:29
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第二段： 由于在普通酒精中I或II与硫化氢的反应混合物中没有发现硫代乙酸或乙硫醇，因此可以排除硫代乙酸或乙硫醇的生成机制。由于不用热水水解，II就会结晶，所以简单的水解法亦可排除。但，在普通酒精和水的混合液中II的稳定性存在一定的问题。在一次实验中，在II在酒精和水以及三乙苯（催化剂）的混合液中经过过夜的搅拌后，II分解产生了无法识别的产物。一个类似的实验表明II仅在普通酒精中是稳定的。 [ Last edited by levone on 2009-5-18 at 11:12 ] |
4楼2009-05-18 11:08:04