【作者】 纪秀杰；

【导师】 张文勤； 李春葆；

【作者基本信息】 天津大学 ， 化学工艺， 2007， 博士

【摘要】 酚酯类化合物是医药、染料、新材料等产品的重要有机中间体。酚酯类保护基也是实施酚羟基保护的经济而有效的方法。选择性去酰基化和去磺酰化反应是有机合成和酚羟基保护过程中比较重要的反应类型,对于试剂廉价、选择性好、产率高、条件温和的方法更有助于合成所需要的化合物以及保护基的发展和应用。本文第一部分主要研究了邻位硝基的促进作用在与Lewis酸三氯化铝络合下的多酚酯的选择性去酰基化和多磺酸酯的选择性去磺酰化反应中的应用。实验中主要以三氯化铝为催化剂,以三氯甲烷为溶剂,将一系列不同酰基的酚酯和不同磺酰基的磺酸酯分别进行选择性去酰基化和去磺酰化反应从而得到相应的硝基酚酯和硝基磺酸酯,不同于Fries重排的产物,并对此方法和机理进行了研究。对产物进行了表征,探索了影响反应的各个因素,优化了反应条件,并首次提出这类反应的机理。实验发现:大多数反应在室温条件下进行,无水三氯化铝用量为1.0².0 eq.,在十小时以内完成反应。结果表明,用此方法将多酚酯进行选择性去酰基化和多磺酸酯进行选择性去磺酰化反应,产率高,选择性好,所用试剂三氯化铝无毒便宜,反应条件较温和,该方法是一种很好的选择性去酰基化和去磺酰化方法。针对一系列不同的酚酯和磺酸酯,在同一Lewis酸三氯化铝存在下的对比反应结果,以及根据采用不同的Lewis酸进行对比实验的结果,还根据对该选择性反应实验过程中产生的氯化产物经气相色谱和气质联用进行定量和定性分析的结果,我们首次提出了酚酯和磺酸酯的邻位硝基使三氯化铝和硝基上氧以及硝基邻位的酚氧基络合,这种络合作用促进了酚酯的选择性去酰基化和磺酸酯的选择性去磺酰化,使硝基邻位的酰基或磺酰基脱去,而和硝基相间或相对的酯基稳定存在的这一类反应的机理。我们首次研究了硝基多磺酸酯的选择性去磺酰化方法,选择性去磺酰化产物是一类新型化合物,羟基是供电子基团,尤其在碱性条件下,我们推测,这将对磺酰氧和芳环碳形成的碳氧键会有显著影响,会在有机合成中有潜在应用。本文第二部分主要对碘、氧化叔胺双重催化的过氧化氢氧化苄醇的绿色新反应进行了初步研究。采用I2-R3NO-H₂O₂催化氧化体系对一系列苄醇进行了催化氧化,反应过程中我们加入催化量的碘和催化量的氧化叔胺,同时加入当量的绿色氧化剂过氧化氢,以三氯甲烷和等体积水为溶剂,将苄醇氧化成酮或醚。实验发现,用此方法对一系列苯基乙醇类苄醇进行反应生成了相应的酮,没有其它副产物生成;对于苯基丙醇类苄醇,多数反应较好,也生成了相应的酮,除了1-（4-丁氧基苯基）丙醇的催化氧化有66%醚产物生成;对于苯基丁醇类苄醇,苯基正丁醇反应生成酮的产率为81%,而苯基异丁醇反应则生成81%的醚产物;对于更长碳链的苯基苄醇,几乎都得到了醚产物。通过核磁共振、红外光谱等方法对产物的结构进行了表征,优化了反应条件,并提出这类反应可能的机理。结果表明,这是一种具有条件温和、试剂廉价、收率较高、操作简单、符合绿色化学概念等优点的绿色催化氧化方法。氧化脂肪叔胺作为催化剂尚属首次,碘分子作催化剂氧化醇类化合物未见文献报道。我们相信,这种绿色新反应将有助于解决氧化反应所带来的环境问题并降低产品的成本,会在科学研究和化工生产中有一定的应用。更多还原

【Abstract】 Phenolic esters are important organic intermediates. They are used in synthesizing pharmaceutical products, dyes and new materials and so on. Phenolic esters provide effective protections for phenolic hydroxyl groups. Selective deacylation and desulfonation will yield new type of esters and sulfonates. Our research has been oriented in discovering mild, selective and high yielding procedures for these types of compounds.We started from 2-nitro-1, 4-diphenolic esters using AlCl3 at 20oC in anhydrous chloroform, the substrates were selectively deacylated into 4-hydroxyl-3-nitro-phenolic esters. In the selective deacylation of 4-nitro-1, 3-diphenolic esters yielded the corresponding 3-hydroxyl-4-nitro-phenolic esters.Similarly, when we started from 2-nitro-1, 4-diphenolic sulfonates, selective desulfonation yielded the 4-hydroxyl-3-nitro-phenolic sulfonates. In the selective desulfonation of 4-nitro-1, 3-diphenolic sulfonates yielded the corresponding 3-hydroxyl-4-nitro-phenolic sulfonates. Thus a series of nitro substituted phenolic esters and sulfonates were synthesized in high yields and at high reaction rates. The structures of the products were fully characterized by1HNMR, 13CNMR, IR and ESI-MS.In most cases, the selective reaction of aliphatic esters needed 1.0-2.0 eq. of AlCl3, and took less than 10 hours at room temperature for completion. But for aromatic carboxylic esters and aromatic sulfonates, higher reaction temperatures and longer reaction times were needed. The reaction conditions were optimized according to different phenolic esters and sulfonates. By comparing the reaction rates of the deacylation and desulfonation, a general mechanism represented by desulfonation directed by the nitro group is proposed. Thus we have established a new procedure for the selective deacylation and desulfonation of polyphenolic esters directed by a nitro group. The regioselectivity is excellent and the reaction rate and yield are high. The products are useful intermediates in organic synthesis.These reactions demonstrate that a nitro group on a phenolic ester or sulfonate has a better ability to complex with AlCl3 than an isolated phenolic ester group does (Fries rearrangement). The directing effect of the o-nitro group was demonstrated for the first time in the selective deacylation and desulfonation for the excellent regioselectivities and good yields.Selective desulfonation of polyphenolic sulfonates has never been realized before. This represents the first selective desulfonation procedure of polyphenolic sulfonates. The products of the selective desulfonation are new types of compounds. The hydroxyl group is electron donating, especially under basic conditions. We speculate that this would dramatically influence the behavior of the aryl carbon and the sulfonoxy oxygen bond and find potential applications in organic synthesis. In the second part of the paper, a new green procedure of biscatalytic oxidation of benzyl alcohols by tertiary amine oxides, iodine and hydrogen peroxide was developed preliminarily. A series of benzyl alcohols were oxidated to the corresponding ketones or ethers using 0.1 eq. I2, 0.1 eq. R3NO and 1.2 eq. H2O2 in chloroform and water.Starting from a series of 1-phenylethyl alcohols, the corresponding ketones were obtained. However oxidation of 1-phenylpropyl alcohols yielded the corresponding ketones and the side product ethers were formed as well. In the oxidation of homologous compounds yielded mainly the corresponding ethers. The structures of the products were fully characterized by 1HNMR, IR and GC. The reaction conditions were optimized according to different benzyl alcohols. By comparing the reaction results of biscatalytic oxidation, a general mechanism is proposed. The results show that we have developed a new procedure on the green oxidation of benzyl alcohols using hydrogen peroxide catalyzed jointly by iodine and tertiary amine oxides. The reaction conditions are mild, the oxidant green and the yields good. This represents the first example of using aliphatic tertiary amine oxides as organocatalyst and the iodine molecule as catalyst in oxidation of alcohols.更多还原