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1.
用不同取代基对化学发光物质6-芳基-2-甲基咪唑[1,2-α]吡嗪-3-(7H)酮环(海萤发光的类似物)的芳基位进行取代,形成系列海萤荧光素类似物MIPa-MIPd;并采用B3LYP/6-311+G(d,p)方法,通过电子抽取能(EEP)的计算和自然电荷布居分析(NPA),研究了在气相、二甲亚砜(DMSO)和二甘醇二甲醚(DG)中海萤发光的类似物从阴离子变化到自由基过程中取代基的作用.结果表明:在这个过程中,吲哚在DG中作为取代基(MIPb)时的EEP最小,电荷变化最大,说明这种取代基有利于反应的进行.  相似文献   

2.
(3E)-胆甾-4-烯-3,6-二酮-3-肟及其类似物的合成   总被引:4,自引:0,他引:4  
崔建国  范磊  黄立梁  肖蓉  黄燕敏 《合成化学》2007,15(6):689-692,743
以胆甾醇为原料,经氯铬酸吡啶氧化生成胆甾-4-烯-3,6-二酮(2),2与盐酸羟胺反应合成了(3E)-胆甾-4-烯-3,6-二酮-3-肟(3),总收率66%。利用合成3的反应条件合成了两个3的类似物——(3E)豆甾-4-烯-3,6-二酮-3-肟(6)和(3E)-谷甾-4-烯-3,6-二酮-3-肟(7)。2,3,6和7的结构经NMR和IR表征。  相似文献   

3.
以2-氰基-6-羟基苯并噻唑为原料,与溴乙醛缩二乙醇缩合制得缩醛后再水解合成中间体6-(2-羰乙基)苯并[d]噻唑-2-甲腈(2);7-苯乙酰氨基-3-氯甲基头孢菌烷酸二苯甲酯依次经碘代和Wittig反应得(Z)-3-[3-(2-氰基苯并[d]噻唑-6-氧)丙-1-烯]-8-羰基-7-(2-苯乙酰氨基)-5-噻-1-氮[4.2.0]辛-2-烯-2-甲酸二苯甲酯(5);5经脱保护、缩合和氧化反应合成了3个新的Bluco类似物,其结构经1H NMR,13C NMR和HR-MS(ESI)表征。  相似文献   

4.
以双(2-羟基-3,5-二氯苯基)甲烷(4)与PSCl3关环,高收率地得到2,4,6,8,10-五氯-6-硫-12H-双苯并[d,g][1,3,2]二氧磷杂八环(5)。5与酚在无水K2CO3及铜粉存在下,或与醇在醇钠存在下反应,生成2,4,8,10-四氯-6-硫-6-芳氧基-12H-双苯并[1,3,2]二氧磷杂八环(6),或6-烷氧基的类似物(7)。5与醇在三乙胺存在下反应的产物为2,4,8,10-四氯-6-硫-6-羟基-12H-双苯并[1,3,2]二氧磷杂八环三乙胺盐(8)。8在DMSO中回流则氧化为它的氧类似物9。  相似文献   

5.
以2-氯苯甲酸和1-氨基萘为原料制备了7-氯苯并吖啶(3);3分别与吗啉,N-甲基哌嗪,金刚烷胺,2,4-二甲基-6-巯基咪唑,N,N-二甲基乙二胺和5-氨基-3-巯基-1,2,4-三氮唑反应,合成了6个新型的氮蒽酮类似物,其结构经1H NMR和IR表征。  相似文献   

6.
张建兴  黄德音 《有机化学》1996,16(2):157-159
异氰酸苯酯和N-[2-(4, 6-二甲基)-嘧啶基]-羟胺(5)反应生成1-[2-(4, 6-二甲基)-嘧啶基]-1-羟基-3-苯基脲(6)。化合物(6)在三乙胺存在下和氯甲酸乙酯反应生成2-[2-(4, 6-二甲基)-嘧啶基]-4-苯基-1, 2, 4-恶二唑烷-3, 5-二酮(1)。  相似文献   

7.
李宝宗 《化学研究》2007,18(1):54-56
采用密度泛函理论,在B3LYP/6-311G**基组水平上,计算并考察了4(3H)-嘧啶酮及其类似物(5-氟-4(3H)-嘧啶酮、4-巯基嘧啶和5-氟-4-巯基嘧啶)醇式结构和酮式结构进行结构互变质子迁移过程中的2种可能途径:(a)分子内质子迁移;(b)水助质子迁移.计算结果表明,途经b所需要的活化能较小.研究还表明,氢键在降低反应活化能方面起着重要的作用.  相似文献   

8.
硅亚胺作为亚胺的重元素类似物,是一类重要的含硅多重键化合物.本研究首次报道了氮杂环卡宾诱导下二胺基氯硅烷脱除Me3Si Cl来制备硅亚胺的方法.合成了二胺基氯硅烷[Ar N(Si Me_3)]_2SiHCl(2)(Ar=2,6-i-Pr_2C_6H_3),通过~1H NMR,~(13)C NMR,~(29)Si NMR,红外以及元素分析的表征确定了2的结构.研究了2与不同位阻氮杂环卡宾的反应性,发现其与位阻较大的1,3-二叔丁基咪唑-2-亚基(It Bu)和1,3-二异丙基-4,5-二甲基咪唑-2-亚基(Ii Pr)均不反应,但是其与位阻较小的1,3,4,5-四甲基咪唑-2-亚基(IMe_4)反应生成氢化硅亚胺3.  相似文献   

9.
包公藤甲素及其类似物的绝对构型研究   总被引:4,自引:0,他引:4  
王朴  姚天荣  陈泽乃 《化学学报》1989,47(10):1002-1006
本文采用Pr(dpm)3诱导CD裂分Cotton效应法、激子手性法和Horean法对新缩瞳剂包公藤甲素(1)及其类似物包公藤丙素(2)、凹脉丁公藤碱(3)及两者的N-甲基化物(4、5)进行了研究。确定了它们的绝对构型分别为: (2S, 6S)2β-羟基-6β-乙酰氧基去甲莨菪烷、(2S, 6S)-2β, -6β-二羟基去甲莨菪烷、(2S,7R)-2β, 7β-二羟基去甲莨菪烷、(2S, 6S)-2β, 6β-二羟基莨菪烷和(2S, 7R)-2β, 7β-二羟基莨菪烷。通过构象分析和用绝对构型已知的化合物验证, 初步解释了Horeau法的测定结果。  相似文献   

10.
采用密度泛函理论(DFT)在B3LYP/6-31G(d)水平上研究了双[1,2-二(三氟甲基)乙烯-1,2-二硫基]镍(Ni[S2C2(CF3)2]2)与丁二烯的反应机理.采用极化连续介质模型(PCM),考察了溶剂对各反应驻点的电荷分布、偶极矩、溶剂化自由能的影响.计算结果表明:Ni[S2C2(CF3)2]2与丁二烯的反应为前线轨道对称性匹配的协同反应,溶剂介电常数的增大有利于稳定各反应驻点.同时在同种溶剂中,过渡态和产物稳定的程度大于反应物,从而反应更加容易进行.  相似文献   

11.
Cypridina luciferin from the luminous ostracod Cypridina (Vargula) hilgendorfii has an imidazopyrazinone core structure (3,7-dihydroimidazopyrazin-3-one), which is identical to that of coelenterazine. Cypridina luciferyl sulfate (3-enol sulfate of Cypridina luciferin) was isolated for the first time and the chemical structure was identified by LC/ESI–TOF–MS analysis. Furthermore, Cypridina luciferyl sulfate was chemically synthesized, and its absorption and MS/MS spectra were in agreement with that of Cypridina luciferyl sulfate isolated. Using the crude extracts of Cypridina specimens, Cypridina luciferyl sulfate could be converted to Cypridina luciferin in the presence of adenosine 3′,5′-diphosphate (PAP), and Cypridina luciferin was converted to Cypridina luciferyl sulfate in the presence of 3′-phosphoadenosine 5′-phosphosulfate (PAPS). These results suggested that a sulfotransferase catalyzes the reversible sulfation of Cypridina luciferin in Cypridina hilgendorfii. In aqueous solution, Cypridina luciferyl sulfate was more stable than Cypridina luciferin and might be a storage form of Cypridina luciferin.  相似文献   

12.
In the luminous ostracod Cypridina (presently Vargula) hilgendorfii, Cypridina luciferyl sulfate (3‐enol sulfate of Cypridina luciferin) is converted to Cypridina luciferin by a sulfotransferase with 3′‐phosphoadenosine‐5′‐phosphate (PAP) as a sulfate acceptor. The resultant Cypridina luciferin is used for the luciferase–luciferin reaction of Cypridina to emit blue light. The luminescence stimulation with major organic cofactors was examined using the crude extracts of Cypridina specimens, and we found that the addition of coenzyme A (CoA) to the crude extracts significantly stimulated luminescence intensity. Further, the light‐emitting source in the crude extracts stimulated with CoA was identified as Cypridina luciferyl sulfate, and we demonstrated that CoA could act as a sulfate acceptor from Cypridina luciferyl sulfate. In addition, the sulfate group of Cypridina luciferyl sulfate was also transferred to adenosine 5′‐monophosphate (5′‐AMP) and adenosine 3′‐monophosphate (3′‐AMP) by a sulfotransferase. The sulfated products corresponding to CoA, 5′‐AMP and 3′‐AMP were identified using mass spectrometry. This is the first report that CoA can act as a sulfate acceptor in a sulfotransferase reaction.  相似文献   

13.
The bioluminescence of the American firefly Photinus is due to the reaction of 2-(6-hydroxybenzothiazol-2-yl)-Δ2-1,3-thiazoline-4-carboxylic acid (“firefly luciferin”) with the enzyme luciferase in the presence of ATP and magnesium ion. In the crustacean Cypridina, on the other hand, the bioluminescence is due to the reaction of a luciferase with 8-(3-guanidinopropyl)-6-indol-3-yl-2-(1-methylpropyl)-3,7-dihydroimidazo[1,2-a]-pyrazin-3-one (“Cypridina luciferin”). The luciferin in Latia is 1,3,3-trimethyl-2-(4-formyloxy-3-methyl-3-butenyl)-1-cyclohexene and that in Renilla is a tryptamine derivative that has not yet been accurately identified; the luciferins of other luminescent organisms are not yet known. A review is given of the investigations which have been carried out on the above luciferins and the course of the luciferin-luciferase reaction is examined. Numerous spectral data obtained during the examination of these compounds are included in the text.  相似文献   

14.
Shin-ichi Kato  Makoto Ojika 《Tetrahedron》2004,60(50):11427-11434
In a luminous ostracod Cypridina (Vargula) hilgendorfii, Cypridina luciferin with an imidazopyrazinone structure (3,7-dihydroimidazopyrazin-3-one) is utilized for the luminescence reaction. To identify the biosynthetic units of Cypridina luciferin, the stable isotope labeled compounds were examined by feeding experiments with living Cypridina specimens. The incorporation of the labeled compounds into Cypridina luciferin was identified by the method of LC/ESI-TOF-MS analyses and these results suggested that l-tryptophan, l-arginine and l-isoleucine are structural units of Cypridina luciferin.  相似文献   

15.
Cypridina luciferin is the substrate in the bioluminescence of a luminous ostracod Cypridina (Vargula) hilgendorfii. Cypridina luciferin contains a chiral center in the sec-butyl moiety. Here, we report a convenient method for the preparation of (S)-Cypridina luciferin by the condensation of (S)-1,1-diethoxy-3-methylpentan-2-one with ethioluciferin. The light yield of the synthesized (S)-luciferin in the presence of Cypridina luciferase was about 1.7 times as active as that of racemic form. Furthermore, several luciferin analogs prepared by the same condensation with different α-ketoacetal derivatives showed moderate light yield with Cypridina luciferase. These readily available Cypridina luciferin and analogs are applicable to the bioluminescent detection of Cypridina luciferase.  相似文献   

16.
The chemiluminescence of 6-aryl-2-methylimidazo[1,2-a]pyrazin-3(7H)-ones (Cypridina luciferin analogues) in DMSO/1,1,3,3-tetramethylguanidine and in diglyme/acetate buffer was investigated. The results indicate that the reaction mechanism that produces a high chemiluminescence quantum yield involves a chemiexcitation process from a neutral dioxetanone intermediate possessing an electron-donating aryl group (σAr <−0.6) to the singlet-excited state of neutral acetamidopyrazine. This result may be applied to the reaction mechanism for Cypridina (Vargula) bioluminescence.  相似文献   

17.
Mechanochemical analogues have recently been established for several enzymatic reactions, but they require periodic interruption of the reaction for sampling, dissolution, and (bio)chemical analysis to monitor their progress. By applying a mechanochemical procedure to induce bioluminescence analogous to that used by the marine ostracod Cypridina (Vargula) hilgendorfii, here we demonstrate that the light emitted by a bioluminescent reaction can be used to directly monitor the progress of a mechanoenzymatic reaction without sampling. Mechanical treatment of Cypridina luciferase with luciferin generates bright blue light which can be readily detected and analyzed spectroscopically. This mechanically assisted bioluminescence proceeds through a mechanism identical to that of bioluminescence in solution, but has higher activation energy due to being diffusion‐controlled in the viscous matrix. The results suggest that luciferases could be used as light‐emissive reporters of mechanoenzymatic reactions.  相似文献   

18.
合成了酰胺多胺配体(L),测定了5,10,15和25℃时其Cu(Ⅱ)配合物的稳定常数,用标准摩尔焓变ΔHm0和标准摩尔熵变ΔSm0解释了温度对稳定性的影响,并利用停流技术(Stopped-flow)研究了CuL配合物在0.04~2.3mol/L(I=2.34mol/LNaCl)盐酸溶液中的酸分解动力学.提出了反应机理,并求得了速控步骤的活化能Ea,标准摩尔活化熵Δ≠Sm0和标准摩尔活化焓Δ≠Hm0  相似文献   

19.
We have investigated theoretically the gas phase reactions of dimethyl sulfoxide (DMSO) with atom Cl in the absence and presence of a single water molecule. The calculations of the potential energy surfaces in the water-free and water-assisted along the different channels are performed at the CCSD(T)/6-311++G(2df,2p)//MP2/6-31G(d) level. The calculated results show that energy barriers of the Hc-abstraction reaction are reduced due to one water molecule added. The computed rate constants of Hc-abstraction reaction indicate that the reaction with water is faster than the value of the naked reaction. However, Ha-abstraction reaction, path2, path3, and path4 are slower without water than hydrous channels.  相似文献   

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