【作者】 杨晓慧；

【导师】 周永红；

【作者基本信息】 中国林业科学研究院 ， 林产化学加工工程， 2011， 博士

【摘要】 从天然生物质资源中分离提纯单体作为先导化合物,进行化学改性修饰,合成新型具有生物活性的化合物,是利用生物质资源制备高附加值深加工产品的重要途径。木质素是除纤维素以外的第二大可再生植物资源,在木材水解和制浆造纸工业中作为废液被回收,但因其化学成分组成复杂工业化利用率低,所以其中大量回收的木质素通常作为燃料使用,有的甚至未经处理直接排放,造成严重的资源浪费和环境污染。因此,研究工业回收木质素的反应分离技术,得到高纯度化合物,进行高价值项目的开发应用,对于综合治理造纸工业废水污染、充分利用天然资源具有重要的现实意义。反应分离技术是现代化工分离提纯的重要手段之一,尤其是在天然产物的分离工艺中具有重要意义。本文以木质素为原料,经碱性硝基苯氧化、分离提纯得到了三种芳香醛类化合物——香草醛、丁香醛和对羟基苯甲醛,其分离纯度分别为98.4%、99.1%和97.6%,总产率最高可达18%;并利用新型低毒的氧化剂A和B从木质素中反应分离得到了愈创木酚、紫丁香醇、香草乙酮和乙酰丁香酮等其它几种重要的化工原料。另外,对从木质素氧化降解产物中分离提纯的醛类化合物进行了如下合成修饰,并且对新化合物进行了生物活性筛选和构效研究:1)利用芳香醛,异腈和2-氨基吡啶通过三组分反应快速高效的合成了19种新型咪唑并[1,2-a]吡啶类化合物,所有化合物表现出了较好的产率(83~94%),并利用IR、1H NMR、13C NMR和HPLC-ESI-MS对所有合成的化合物进行了结构表征。采用滤纸片法测试了该类化合物的抑菌活性,抗菌活性筛选结果表明该类化合物4b(iii)、4f(iii)和4s(iii)对大肠埃希菌,绿脓杆菌,金黄色葡萄球菌以及链球菌没有明显抑制效果,但抗血吸虫活性正在测试中。2)以三种芳香醛,苯肼和β-酮酯为原料高效合成了一系列的双吡唑醇类化合物,所有合成化合物的产率都比较理想(≥82%);并通过清除二苯基代苦味酰基(DPPH)和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)自由基分析对所有的化合物进行了抗氧化研究。结果表明:相对于标准品Trolox,所有化合物都表现出较好抗氧化性能,特别是化合物4a(iv)和4d(iv)的抗氧化性能较好,具有进一步开发的价值。3)通过微波辅助Hantzsch反应一锅高效的合成了一系列的4-芳基六氢喹啉酮衍生物,产率高达89%以上;并通过清除二苯基代苦味酰基(DPPH)和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)自由基分析对所合成的化合物5a-c(v)、5g-i(v)的抗氧化性能进行了评价,并对其构效关系进行了研究。结果表明:相对于标准品Trolox,化合物5a(v)和5g(v)的抗氧化性能最好;5b(v)和5h (v)次之,5c(v)和5i(v)最差。从构效关系看,甲氧基的引入使其抗氧化性能明显增加,其抗氧化顺序为4-羟基-3,5-二甲氧基苯基取代的六氢喹啉酮的抗氧性能,大于4-羟基-3-甲氧基苯基取代的六氢喹啉酮,远远大于4-羟基-3,5-二甲氧基苯基取代的六氢喹啉酮。4)通过Hantzsch一锅三组分反应高效合成了一系列的4-芳基-l,4-二氢吡啶和9-芳基-十氢吖啶衍生物。除化合物6c(vi)没有得到产物外,其它化合物的产率都比较理想(≥79%);并通过清除二苯基代苦味酰基(DPPH)和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)自由基分析对4-羟基-3,5-二甲氧基取代的1,4-二氢吡啶4a(vi)和多氢吖啶6a(vi),以及4-羟基-3-甲氧基取代的1,4-二氢吡啶4b(vi)、4e(vi)和多氢吖啶6b(vi)的抗氧化性能进行了评价。结果表明:相对于标准品Trolox,化合物4a(vi)和6a(vi)具有良好的抗氧化性能;鉴于化合物4a(vi)、6a(vi)和6b(vi)较好的抗氧化性能,我们又对它们的降血压活性进行了研究,与对照组以及自身给药前比较,化合物4a(vi)和6a(vi)具有一定的降血压效果,具有进一步应用开发的价值。5)以芳香醛化合物、β-酮酯、丙二腈和肼为原料便利高效的合成了一系列的4-芳基-二氢吡喃并[2,3-c]吡唑衍生物。除化合物7e(vii)和7g(vii)外,所有化合物都有很好的产率(≥70%)。并通过清除二苯基代苦味酰基(DPPH)和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)自由基分析对所合成的化合物6a(vii)、6d-f(vii)、6j(vii)、7d(vii)和7g(vii)的抗氧化性能进行了评价。结果表明:相对于标准品Trolox,6a(vii)、6d(vii)、6j(vii)、7d(vii)和7g(vii)都展示了优秀的抗氧化性能,特别是在ABST+分析中,所有所测化合物的IC50都远远比标准品Trolox低,几乎只有标准品的千分之一,表现出非常优秀的ABST+自由基清除活性。这表明它们具有潜在的药物用途,同时也为木质素的高附加值利用提供了一条有效的途径。6)利用微波辅助的多组分反应快速高效的合成了27种3-氰基吡啶类化合物,产率高达63~85%,并通过并通过清除二苯基代苦味酰基(DPPH)自由基分析对化合物5b(viii)、5h(viii)、5i(viii)、7d(viii)、7e(viii)、7f(viii)以及7k(viii)的抗氧化性能进行了测定,结果表明该类化合物的抗氧化性能相对较差;但正将其应用于抗血吸虫的研究中。通过对构效关系研究发现:4-羟基-3,5-二甲氧基苯基取代的杂环化合物比4-羟基-3-甲氧基苯基和4-羟基苯基取代的杂环化合物具有更好的抗氧化及降压活性,亦即表明利用丁香醛合成抗氧化剂和降压药比香草醛和对羟基苯甲醛效果要理想。更多还原

【Abstract】 Separating monomeric compounds from biomass resources and then using them to synthesize new compounds and research their biological activities are a significant way in deep processing of high value-added products from biomass resources. Lignin is the second most abundantly renewable natural plant resources except cellulose richly found in wood hydrolysis and papermaking waste, used as fuel and even discharged without any treatment process, causing severe environmental pollution because it?s complicated structure and low industrial application rate. Researching on the value-added utilization of lignin by reaction–separation and modification of lignin degradation products is of very significant importance to make full use of natural resource and also to waste water treatment.Reaction-separation technology is one of important method in modern separation and purification, which is particularly tremendous significance in separation of natural produacts. In this paper, syringaldehyde, vanillin and p-hydroxybenzaldehyde were prepared from lignin via alkaline nitrobenzene oxidation with total yield 18% (purity 98.4%, 99.1% and 97.6%, respectively); Guaiacol, lilac alcohol, acetovanillone, acetosyringone were also obtained from lignin through new and low-toxicity oxidants A and B. In addition, Several series of new compounds were prepared using aromatic aldehydes obtained from lignin and screened for their biological activities to research their Structure-activity relationship:1) A convenient protocol is described for the preparation of 3-amino-imidazo[1,2-a] pyridine derivatives via three-component reactions between 2-aminopyridine derivatives, aldehydes and isocyanides with excellent yields (83~94%). All the compounds were characterized by IR, 1H NMR, 13C NMR, and HPLC-ESI-MS. In addition, their antibacterial activities were tesed by filter paper method. The result showed that these compounds 4b(iii), 4f(iii) and 4s(iii) had no inhibiting effects on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus, but they are being screened for anti-schistosomiasis activities. 2) A series of novel bispyrazoles joined by arylmethylene at C-4 position were synthesized in good to excellent yield (≥82%) using aromatic aldehydes obtained from lignin and screened for their antioxidant activities by N,N-diphenyl-N′-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylenzothiazoline-sulphonic acid) (ABTS+) radical scavenging assays. All of these compounds exhibited good DPPH and ABST+ radical scavenging activities as compared to the standard, Trolox. Especially, the compound 4a(iv) and 4d(iv) had better antioxidant activities, which suggested their potential as promising agents for curing tumors or other free radical-related diseases.3) A series of 4-aryl-hexahydroquinolines were prepared by microwave assisted Hantzsch reaction using aromatic aldehydes obtained from lignin, 1,3-cyclohexanediones,β-ketoesters and ammonium carbonate with good yields (≥89%). The antioxidant properties of 5a-c(v), 5g-i(v) were evaluated by two methods: scavenging effect on DPPH radical and scavenging effect on ABTS+ radical. Compounds 5a and 5g showed the best antioxidant activities against DPPH and ABST+, 5b(v) and 5h(v) were second, 5c(v) and 5i(v) were relatively bad. In addition, the results showed that the compounds containing methoxy moiety linked at the aryl substituents of the 4-aryl-hexahydroquinolines increased their biological activities; the activity order of them is as follows: 4-(4-hydroxy-3,5-dimethoxyphenyl) hexahydroquinolines > 4-(4-hydroxy-3-methoxyphenyl) hexahydroquinolines >> 4-(4-hydroxyphenyl) hexahydroquinolines.4) One-pot condensation of 1,4-dihydropyridines and 9-arylpolyhydroacridines with aromatic aldehydes obtained from lignin in the presence of ammonium carbonate was carried out in water with good yields (≥79%) except compound 6c(vi). Antioxidant properties of compounds 4a(vi), 4b(vi), 4e(vi), 6a(vi) and 6b(vi) were evaluated by scavenging DPPH and ABTS+ radical effects. Compounds 4a(vi) and 6a(vi) showed the best antioxidant activities against DPPH and ABST+. In addition, Compounds 4a(vi) and 6a(vi) also exibited good hypotensive properties, which suggested them deserving to further development and application.5) A series of novel 1H,4H-dihydro-pyrano[2,3-c]pyrazoles were synthesized via muti-component reaction with aromatic aldehydes obtained from lignin, and screened for their antioxidant activities by DPPH and ABTS+ radical scavenging assays. Except compound 7e(vii) and 7g(vii), all the other compound yielded well (≥70%). In addition, to our surprise, those compouds 6a(vii), 6d(vii), 6j(vii), 7d(vii) and 7g(vii) showed excellent antioxidant properties. Their values of IC50 were lower than that of Trolox in the DPPH and ABST+ radical cation scavenging assays. Especially, their values of IC50 were 1 000 times lower than that of Trolox in reaction with ABST+ radical. The strong antioxidant abilities of these compounds indicated their potential usefulness in the drug development, thus providing an effective approach for value-added application of lignin.6) 27 kinds of 3-cyanopyridine derivatives were prepared via convenient, rapid and environmentally benign four-component reactions between 2-substituted acetophenones, aromatic aldehydes, malononitrile and ammonium acetate under microwave irradiation with good yield (63~85%); the compounds 5b(viii), 5h(viii), 5i(viii), 7d(viii), 7e(viii), 7f(viii) and 7k(viii) were screened for their antioxidant activities by DPPH radical scavenging assays. The results showed that they had poor antioxidant properties, but they are being screened for anti-schistosomiasis activities.Through structure-activity relationship analysis, it was found that 4-hydroxy-3,5-dimethoxyphenyl heterocyclic compounds had better antioxidant and hypotensive activities than 4-hydroxy-3-methoxyphenyl and 4-hydroxyphenyl heterocyclic compounds, i.e, syringaldehyde is the better material for synthsis of antioxidant and hypotensive agents than vanillin and p-hydroxybenzaldehyde.更多还原