含吡唑结构的杂环化合物的合成、结构和抑菌活性的研究

【作者】 李艳；

【导师】 王建武；

【作者基本信息】 山东大学 ， 有机化学， 2009， 博士

【摘要】 论文合成了咪唑并[1,2-b]吡唑类、二吡唑基甲酮类和吡唑连噁二唑类共三类48个化合物,使用了现代结构测试手段对所合成的化合物进行了结构表征,其中两个化合物经过了X-Ray射线衍射分析,并对其中大部分化合物进行了以金黄色葡萄球菌和肺炎克雷白杆菌为代表的革兰氏阳性菌和革兰氏阴性菌的初步抑菌活性测试。论文工作第一部分合成了咪唑并[1,2-b]吡唑类化合物28个,其中包括双（咪唑并[1,2-b]吡唑-3-基）甲烷7个。从两个活泼亚甲基化合物（氰基乙酸乙酯和丙二睛）开始,经过乙烯酮二硫代缩醛（ketene dithioacetal）中间体,合成了两个5-氨基-1H-吡唑,以这个两个化合物为中间体,与芳香族和脂肪族α-溴代酮反应,而后经酸催化亚胺化互变异构后得到含咪唑并[1,2-b]吡唑甲硫醚类化合物6a-6g。咪唑并[1,2-b]吡唑甲硫醚类化合物经过室温下H₂O₂/CH₃COOH温和氧化,得到咪唑并[1,2-b]吡唑甲基亚砜类化合物7a-7g。咪唑并[1,2-b]吡唑甲硫醚类化合物经过50℃下H₂O₂/CH₃COOH剧烈氧化,得到咪唑并[1,2-b]吡唑甲基砜类化合物8a-8g。咪唑并[1,2-b]吡唑甲硫醚类化合物6a-6g在新蒸馏的甲酰胺中回流,得到结构新颖的双（咪唑并[1,2-b]吡唑-3-基）甲烷类化合物9a-9g。考虑到化合物9a-9g结构非常新颖,我们使用了IR、¹HNMR、¹³CNMR、元素分析和ESI-MS等结构测试手段,对该类化合物进行了仔细的结构表征。对构建咪唑并[1,2-b]吡唑骨架的反应的区域选择性进行了细致深入讨论,得到了化合物6a和6b的X-Ray射线晶体结构,为上述区域选择性和咪唑并[1,2-b]吡唑骨架的准确结构提供了确凿的证据。论文工作第二部分合成了二吡唑基甲酮类化合物10个。从第一部分中的中间体5-氨基-1H-吡唑-4-羧酸乙酯开始,经过肼解、与乙烯酮二硫代缩醛的缩合反应和烷基化反应,合成了二吡唑基甲酮类化合物。对反应的化学选择性和区域选择性进行了仔细讨论。论文工作第三部分合成了吡唑连噁二唑化合物10个。从第一部分中的中间体5-氨基-1H-吡唑-4-羧酸乙酯开始,经过烷基化、H₂O₂/CH₃COOH温和氧化、肼解和成荒酸钾盐脱硫反应,合成了吡唑连噁二唑类化合物。对反应路线中涉及到的烷基化反应、形成亚砜的氧化反应和形成噁二唑的环化反应的顺序对合成亚砜化合物18a-18e的影响进行了探讨。对部分合成的最终化合物和少量中间体进行了抑金黄色葡萄球菌和肺炎克雷白杆菌的活性测试,发现所有受测试的咪唑并[1,2_b]吡唑类化合物和二吡唑基甲酮类化合物对标准金黄色葡萄球菌和临床金黄色葡萄球菌的抑菌活性呈现出有规律的结构-活性（SAR）关系,对标准肺炎克雷白杆菌和临床肺炎克雷白杆菌的抑菌活性无明显结构-活性关系,且受测试化合物对金黄色葡萄球菌的抑菌活性普遍比对肺炎克雷白杆菌的抑菌活性好。更多还原

【Abstract】 Three classes, forty-eight in total, of pyrazole compounds, imidazolo[1,2-b] pyrazoles, dipyrazolylmethanones and pyrazolyloxadiazoles, have been synthesized, and they have been fully characterized by modern spectroscopic methods, two of which were further confirmed by X-ray diffraction. Most of these compounds have been evaluated for the inhibitions of Gram-positive bacterium represented by Staphylococcus aureus and Gram-negative bacterium represented by Klebsiella pneumoniae.In the first part of this thesis is presented the synthesis of twenty-eight imidazolo[1,2-b]pyrazoles, including seven bis（imidazolo[1,2-b]pyrazol-3-yl）-methanes.Starting with two reactive methylene compounds, ethyl cyanoacetate and malononitrile, two 5-amino-1H-pyrazoles were prepared through the intermediates ketene dithioacetal. Reactions of 5-amino-lH-pyrazoles with aromatic and aliphaticα-bromoacetophenones, followed by acid-mediated iminative cyclization and the ensuing tautomerization, produced methylthio-imidazolo[1,2-b]pyrazoles 6a-6g. methylthio-imidazolo[1,2-b]pyrazoles 6a-6g were mildly oxidized with H₂O₂/acetic acid at room temperature to yield methylsulfinyl-imidazolo[1,2-b]pyrazoles 7a-7g and violently oxidized with H₂O₂/acetic acid at 50℃to afford methylsulfonyl-imidazolo[1,2-b]pyrazoles 8a-8g.Methylthio-imidazolo[1,2-b]pyrazoles 6a-6g were refluxed in freshly distilled formamide to generate structurally novel bis（imidazolo[1,2-b]pyrazol-3-yl）methanes 9a-9g. Given the structural novelty of 9a-9g, they were fully and unambiguously characterized by IR, ¹H NMR, ¹³C NMR, elemental analyses and ESI-MS.The region-selectivity involved in the construction of imidazolo[1,2-b]pyrazole skeleton was fully investigated and discussed, and the X-ray diffraction of 6a and 6b unequivocally supported the precise structure of imidazolo[1,2-b]pyrazole skeleton.In the second part is described the synthesis of ten dipyrazolylmethanones. The intermediate 5-amino-1H-pyrazole-4-carboxylic acid ethyl ester prepared in the first part underwent successively hydrazinolysis, condensations with ketene dithioacetals and alkylations to give rise to the dipyrazolyhnethanes. The chemo-selectivity and regio-selectivity were also discussed. In the final part is reported the synthesis of ten pyrazolyloxadiazoles. The same intermediate 5-amino-1H-pyrazole-4-carboxylic acid ethyl ester underwent in turn alkylations, mild oxidation with H₂O₂/acetic acid, hydrazinolysis and formation of potassium xanthate followed by desulfurization to give the pyrazolyloxadiazoles. The effect of the order of alkylations, oxidation to form sulfoxides and cyclizations to form oxadiazoles involved in the synthetic route on the synthesis of final pyrazolyloxadiazoles 18a-18e was also investigated and discussed.Part of the final compounds, along with a small amount of intermediates, were tested for the inhibition of Staphylococcus aureus and Klebsiella pneumoniae, and all the tested imidazolo[1,2- b]pyrazoles and dipyrazolylmethanones showed regular structure-activity relationship （SAR） in the inhibition of both standard and clinical Staphylococcus aureus, while neither imidazolo[1,2-b]pyrazoles nor dipyrazolylmethanones displayed noticeably regular SAR in the inhibition of both standard and clinical Klebsiella pneumoniae. The bioactivities in the inhibition of Staphylococcus aureus were more potent than those in the inhibition of Klebsiella pneumoniae.更多还原