氟化物催化硅氢化合物和取代酚的脱氢偶联反应

通过等摩尔竞争反应研究了氟化物催化的硅氢化合物和取代酚的脱氢偶联反应机理。研究表明，ｐ－ＸＣ６Ｈ４ＯＨ在反应中的取代基效应与氟化物催化取代苯甲醛ｐ－ＸＣ６Ｈ４ＣＨＯ的硅氢化反应中的不同，这表明它们的反应机理存在差异，在这两种反应中，虽然Ｆ＾－对Ｓｉ的配位都促进了硅氢化合物中的Ｈ对底物中带正电荷原子的亲核进攻，但是在催化酚解反应中，由于没有四中心过渡态的形成，因此下一步取代酚中的氧原子对Ｆ＾－配位的     

氟化钾催化下取代苯甲醛的硅氢化反应

硅氢化合物对羰基化合物的加成反应是合成含烷氧基硅烷的方法,其产物水解后得醇,因此该反应已作为羰基还原的新方法应用于有机合成。多种催化剂可催化该反应,常见的有:H_2PtCl_6·H_2O、PdCl_2、(Ph_3P)_3RhCl、NiCl_2等。七十年代末期,法国的 Corriu 等人发现了一种新的催化羰基化合物硅氢化的体系,即使用盐类型的氟化物     

氟化钾催化含氢烷氧基硅烷的歧化反应

氟化钾催化含氢烷氧基硅烷的歧化反应张增佑，尚坚，周秀中（南开大学元素有机化学研究所化学系，天津，５０００７１）关键词歧化反应，氟化物，催化，烷氧基硅烷早在７０年代初期Ａｋｌｉｒｅｍ［１］就报道了氟化物可催化硅氢化物醇解。关于氟化物活化Ｓｉ—Ｈ键的实质...     

室温水介质中氟化钾催化的Knoevenagel反应

以氟化钾作为催化剂,在室温水介质中促进芳香醛与活泼亚甲基化合物发生Knoevenagel缩合反应,其反应时间短,条件温和,产率高,产品纯度好,操作和后处理简单,催化剂可重复使用多次.     

铜催化2-（2,2-二溴乙烯基）苯酚化合物与苯酚衍生物的串联醚化反应

首次报道铜催化2-（2,2-二溴乙烯基）苯酚类化合物与苯酚衍生物的串联醚化反应. 以2-（2,2-二溴乙烯基）苯酚衍生物与苯酚类化合物为起始原料,醋酸铜为催化剂、碳酸铯作为碱,在N,N-二甲基甲酰胺中通过一锅法合成了24个未见文献报道的2-芳氧基苯并呋喃类化合物. 此合成方法具有原料易得、操作简便、分离纯化简单和无需昂贵配体等优点.     

无水氟化钾催化酰亚胺与氯乙腈的氰甲基化新方法

用邻苯二甲酰亚胺与二乙胺基乙腈反应进行氰甲基化制备N-氰甲基邻苯二甲酰亚胺,反应温度高、时间长、产率低(160℃、22小时、22.2％)。我们首次用无水氟化钾催化邻苯二甲酰亚胺与氯乙腈的氰甲基化反应,成功地制得了N-氰甲基邻苯二甲酰亚胺,取得了满意的     

相转移催化法合成芳氧基乙酸芳酯及硫赶酸苯酯

用液-液相转移催化法合成了35个芳氧基乙酸芳酯,5个芳氧基硫赶乙酸苯酯,与经典方法相比,相转移催化法有产率较高,反应条件温和,操作简便等优点。     

电石渣负载氟化钾的催化酯交换特性研究

通过浸渍法制备以氟化钾为活性体、电石渣为载体的负载型钙基酯交换催化剂,并在借助X射线荧光光谱仪、热分析天平、X射线衍射仪、氮气吸附-脱附仪、扫描电子显微镜以及哈米特指示剂法等手段对催化剂表征,以及气相色谱仪对原料油成分分析的基础上,通过间歇式酯交换实验系统,从催化剂添加量、醇油物质的量比、酯交换温度与时间等影响因素出发,研究了电石渣负载氟化钾催化花生油与甲醇酯交换的特性。电石渣负载氟化钾后,产生KCaF3、CaF2以及KF等新物相,并且在催化剂添加量为5%、反应温度为62℃、反应时间为2 h以及醇油物质的量比为15的酯交换条件下,能够取得91.58%的甘油收率,相比较氢氧化钙和未有活性体负载的电石渣,其催化酯交换性能得到提高。     

稀土化合物催化丁醛Aldol-Tishchenko反应的研究

1　实　验已有一些用稀土化合物催化Ｔｉｓｈｃｈｅｎｋｏ和Ａｌ ｄｏｘ Ｔｉｓｈｃｈｅｎｋｏ反应的报道[1～ 4 ] ,本文所用的催化剂对空气和水汽都很敏感 ,所有操作均须用Ｓｃｈｌｅｎｋ技术在氩气保护下进行。溶剂四氢呋喃(ＴＨＦ)和甲苯经无水ＣａＣｌ2 干燥 ,使用前经二苯甲酮 钠回流至蓝紫色蒸出。丁醛经 0 .4ｎｍ分子筛干燥后 ,在氩气保护下蒸出。稀土离子含量用ＥＤＴＡ络合滴定法测定。产物的收率在岛津公司生产的ＧＣ 14Ｂ型气相色谱仪上测定。1.1　催化剂的合成　　 (ＭｅＣｐ) 3 Ｌｎ由无水ＬｎＣｌ3与ＭｅＣｐＮａ按 1∶3摩尔…     

叔丁醇钾催化酮硅氢加成反应

介绍了一种用叔丁醇钾催化酮硅氢加成,水解合成醇的方法.以甲苯为溶剂,室温下,叔丁醇钾可高效催化酮与三乙氧基硅烷的硅氢加成反应,酮转化率在90%以上.该方法具有操作简捷、方法简单等优点.     

取代苯酚的脱叔丁基反应

本文对一些取代邻叔丁基苯酚进行脱叔丁基反应作了研究。这一结果可以用脱叔丁基反应和Freidel-crafts反应予以解释。     

Gold catalysis: domino reaction of en-diynes to highly substituted phenols

By Sonogashira coupling of 1,7-heptadiynes and 1,8-octadiynes with 2-iodoallyl alcohols, various substrates that bear a 2-alkynylallyl alcohol moiety tethered to an additional alkyne were prepared in one step. Subjection to nitrogen acyclic carbene (NAC)/gold(I) catalysts delivered highly substituted phenols in an efficient domino reaction. Furan derivatives were formed as intermediates; this was proven by in situ NMR spectroscopy. The uncommon substitution pattern of these furans opens the way for a selective formation of phenols that contain the hydroxyl group in the meta position to the ring junction, which previously was not possible by gold-catalyzed furan-yne cyclization. Furthermore, interesting mechanistic insights were obtained by products derived from secondary allyl alcohols. In this case, in addition to the phenolic compounds, a ketone is formed by 1,2-alkyl shift.     

Degradation of substituted phenols with different oxygen sources catalyzed by Co(II) and Cu(II) phthalocyanine complexes

Research on substituted phenol degradations has received substantial attention. In this work, effective Co(II) and Cu(II) phthalocyanine complexes as catalysts were studied to degrade toxic phenols to harmless products. The effect of various process parameters, such as initial concentration of phenol, catalyst, oxygen sources, and temperature on the degradation reaction was investigated to achieve maximum degradation efficiency. The catalytic activities of Co(II) and Cu(II) phthalocyanines were evaluated for oxidation of phenolic compounds such as p-nitrophenol, o-chlorophenol, 2,3-dichlorophenol, and m-methoxyphenol. Co(II) phthalocyanine displayed good catalytic performance in degradation of 2,3-dichlorophenol to 2,3-dichlorobenzaldehyde and 2,3-dichloro-1,4-benzoquinone with the highest TON and TOF values within 3?h at 50?°C. The fate of catalyst during the degradation process was followed by UV–Vis spectroscopy.     

KF/AL~2O~3催化的羰基与活性亚甲基化合物的缩合反应

在KF/Al~2O~3催化下, 芳香醛与氰乙酸乙酯或氰乙酰胺发生羰基与亚甲基的缩合反应, 得到高产率的缩合产物, 且为E式结构。     

The role of F-N reagent and reaction conditions on fluoro functionalisation of substituted phenols

The effect of steric interactions on the regioselectivity of fluorination of para alkyl substituted phenols was investigated and the strong effect of size of the alkyl substituent, the structure of the F-N reagent and the solvent on the site of fluorination was established. The course of reaction obeyed a second order rate equation, while the fluorination process required higher ΔH^≠ activation than oxidation or oxidative demethylation. Solvent polarity variations had a small effect on the rate of functionalisation, while an excellent Hammett correlation with ρ⁺=−2.3 was determined.     

取代苯酚的Mannich 反应

含有亚氨基二乙酸取代基的酚类化合物常用于二价金属钴、镍、锰的配位滴定以及碱土金属的鳌合剂,工业上用作水的软化剂.我们在寻找放射性核素加速排除药物时,以带有不同取代基团的苯酚、苯二酚与亚氨基二乙酸、甲醛进行 Mannich 反应,合成了十八个含有亚甲氨基二乙酸基取代的酚类衍生物.其中1a~([3]),1b~([1]),1c~([4]),2c~([3]),3a~([4]),3c~([5])及4a~([4])为已知化合物.     

Synthesis of substituted ureas possessing alkyl aromatic fragments via the reaction of 1-(3,3-diethoxypropyl)ureas with phenols

In this article, we report the approach to the substituted ureas based on the reaction of 1-(3,3-diethoxypropyl)ureas with phenols. Depending on the nature of the phenol and urea the reaction leads either to diarylpropane and dibenzoxanthene derivatives or calixarenes. The proposed method benefits from mild reaction conditions, high product yields and operational simplicity.     

Synthesis of substituted phenols by using the ring-closing metathesis/isoaromatization approach

Ring-closing olefin metathesis (RCM) of 4-methylene-1,7-octadien-3-ones 2, followed by isomerization of the carbon--carbon double bond of 6-methylene-2-cyclohexenones 3 from exo to endo, produced various phenols 4. As an application of the method, the RCM/Mizoroki-Heck reaction of 2 was proven to be also effective for the synthesis of phenols having an additional substituent at ortho-benzylic position.     

Hydroxylation of substituted diatomic phenols and their derivatives

Oxidation of 3,6-di-tert-butylpyrocatechol in protic media is accompanied by the formation of 3,6-di-tert-butyl-2-hydroxy-para-benzoquinone. Hydroxylation of the 3,5-isomer results in dealkylation and isomerization with the formation of 6-tert-butyl-2-hydroxy-para-benzoquinone and the quinone mentioned above, respectively. Their ratio depends on the nature of the solvent. Analogous processes accompany redox transformations of 2,6-di-tert-butylhydroquinone, 2,6-diphenyl-para-benzoquinone, and 2,4,6-tri-tert-butylphenol adsorbed on silica gel. Derivatives of 3,5-substituted pyrocatechols formed under conditions of heterophase oxidation in air are capable of transformations to form nitrogen-containing compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2007–2010, October, 1998.