本文選題：吡啶　切入點：C-H鍵　出處：《大連理工大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：含有吡啶結(jié)構(gòu)的酮是合成醫(yī)藥、天然產(chǎn)物、農(nóng)用化學(xué)品、染料等精細化學(xué)品的重要中間體,吡啶側(cè)鏈C-H鍵的氧化是制備此類酮最直接、最高效的合成方法之一。由于吡啶環(huán)的缺電子性,其側(cè)鏈C-H鍵比較難發(fā)生氧化反應(yīng),所以吡啶側(cè)鏈C-H鍵氧化生成酮的研究很少。本論文選擇芐基吡啶類化合物、6,7-二氫-5H-環(huán)戊基[b]吡啶類化合物和2-乙基吡啶作為反應(yīng)底物,研究了吡啶側(cè)鏈C-H鍵氧化生成酮的方法。主要內(nèi)容如下:選擇芐基吡啶類化合物作為反應(yīng)底物,以氧氣為氧化劑,研究了 H_4Nl-AcOH協(xié)同催化吡啶側(cè)鏈C-H鍵氧化生成酮的方法,收率為61-97%。該方法具有優(yōu)異的化學(xué)選擇性,不氧化底物中的芐位甲基、芐位乙基和甲硫基。AcOH和芐基吡啶類化合物反應(yīng)生成的鹽促進了該氧化反應(yīng)。對照實驗證明了 H_4NI和AcOH協(xié)同催化的機理,H_4NI被氧化成I_2,I_2催化該氧化反應(yīng),AcOH不僅參與了H_4NI被氧化成I_2的過程,還提高了反應(yīng)選擇性。~(18)O_2同位素標(biāo)記實驗證明了酮產(chǎn)物中的羰基氧來自于氧氣。電子順磁共振(EPR)實驗表明該氧化反應(yīng)是通過自由基機理進行的。選擇芐基吡啶類化合物、6,7-二氫-5H-環(huán)戊基[b]吡啶類化合物和2-乙基吡啶作為反應(yīng)底物,研究了 Mn(OTf)2催化吡啶側(cè)鏈C-H鍵氧化生成酮的方法,收率為31-88%。相比文獻報道的方法,該方法使用了綠色環(huán)保的氧化劑(65%叔丁基過氧化氫水溶液)替代了 CrO3。文獻報道的方法使用H_2SO_4-HOAc為溶劑,不僅對環(huán)境污染大,而且對設(shè)備腐蝕嚴重,本方法使用H_2O為溶劑,徹底解決了上述問題。通過單晶X射線衍射實驗證明了 6,7-二氫-5H-環(huán)戊基[b]吡啶基-5-酮的結(jié)構(gòu)。將Mn(NO_3)_2和1,10-菲Up啉的絡(luò)合物在氮氣氛圍中煅燒制備了多種MnO_x-N@C,選擇芐基吡啶類化合物和6,7-二氫-5H-環(huán)戊基[b]吡啶類化合物作為反應(yīng)底物,研究了MnO_x-N@C催化吡啶側(cè)鏈C-H鍵氧化生成酮的方法,收率為38-95%。研究發(fā)現(xiàn)MnO_x-N@C(600℃)的催化活性最高。利用透射電子顯微鏡(TEM)和X射線光電子能譜分析(XPS)對MnO_x-N@C(600 ℃)進行了初步表征。在連續(xù)循環(huán)6次后,MnO_x-N@C(600 ℃)的催化活性沒有損失,這說明MnO_x-N@C(600 ℃)具有很好的穩(wěn)定性。
[Abstract]:Ketones containing pyridine structure are important intermediates of synthetic medicine, natural products, agricultural chemicals, dyes and other fine chemicals. The oxidation of C-H bond of pyridine side chain is the most direct way to prepare such ketones. One of the most efficient synthesis methods. Due to the electron deficiency of pyridine ring, the side chain C-H bond is more difficult to oxidize. In this paper, benzylpyridine compounds (6) -dihydro-5H-cyclopentyl [b] pyridines and 2-ethylpyridine (2-ethylpyridine) were selected as the reaction substrates. The method of oxidation of pyridine side chain C-H bond to ketone was studied. The main contents were as follows: benzyl pyridine compounds were selected as reaction substrate and oxygen was used as oxidant to study the method of co-catalytic oxidation of pyridine side chain C-H bond to ketone by H _ 4Nl-AcOH. The yield is 61-97.The method has excellent chemical selectivity and does not oxidize benzyl methyl in the substrate. The oxidation reaction was promoted by the reaction of benzyl ethyl with trimethylthio. AcOH and benzyl pyridine compounds. The mechanism of co-catalysis of H _ (4NI) and AcOH was proved by comparison. The oxidation of H _ 4NI was oxidized to I _ 2N _ (2) and I _ 2i _ (2) was not only involved in the oxidation of AcOH. The process by which H4NI is oxidized to Ist2, In addition, the selectivity of the reaction was improved. The isotopic labeling experiment showed that the carbonyl oxygen in the ketone product originated from oxygen. The electron paramagnetic resonance (EPR) experiment showed that the oxidation reaction was carried out by free radical mechanism. The benzyl pyridine group was selected. The complex of 6-dihydro-5H-cyclopentyl [b] pyridine and 2-ethylpyridine were used as the reaction substrates. The method of oxidation of pyridine side chain C-H bond to ketone catalyzed by Mn(OTf)2 was studied in the yield of 31-88. This method uses 65% hydrogen peroxide solution of environmental protection oxidant) instead of CrO3.The method reported in the literature uses H _ 2SO _ 4-HOAc as solvent, which not only pollutes the environment but also corrodes the equipment seriously. This method uses H _ 2O as solvent. The above problems have been solved thoroughly. The structure of 6o 7-dihydro-5H-cyclopentyl [b] pyridyl [b] pyridyl 5-one has been proved by single crystal X-ray diffraction. The complexes of Mn(NO_3)_2 and 1O10-phenanthroline have been calcined in nitrogen atmosphere to prepare a variety of MnOx-Nx-Nappa Con, and benzyl benzyl has been selected. Pyridines and 6-dihydro-5H-cyclopentyl [b] pyridine as reaction substrates, The oxidation of pyridine side chain C-H bond to ketone catalyzed by MnO_x-N@C was studied. The yield was 38-95. It was found that the catalytic activity of MnO_x-N@C(600 鈩，

本文編號：1612654