新型木脂素的合成及分子内芳环非酚氧化偶合反应机理

采用 ＤＤＱ（２,３－二氯－５,６－二氰基－１,４－苯醌）作为非酚氧化偶合试剂,通过对合不同取代基芳环化合物的１,４－二芳基丁烷与ＤＤＱ在ＴＦＡ（三氟乙酸）中进行非酚氧化偶合和重排反应的研究,通过分子内非酚氧化偶合反应得到了苯并呋喃新型木脂素,经药理筛选发现此类新型木脂素对中枢神经有强的抑制作用．发现芳环上取代基对此类反应的影响很大,尤其是在芳基上苄基的对位有供电子基团是此类反应能够进行的必要条件．     

通过芳磺酸酯不同化学键的可选择性断裂构建不同的芳基醚

实现了利用芳磺酸酯作原料通过各种化学键的选择性断裂制备芳基烷基醚和二芳基醚, 实现了利用吸电子基取代的芳磺酰氯与酚的反应来制备二芳基醚. 在K₂CO₃作用下, 分别利用酯基部分苯环上是吸电子基取代的芳磺酸芳基酯通过S―O键断裂与醇的反应, 芳磺酸烷基酯通过C―O键断裂与酚的反应来合成芳基烷基醚. 在K₃PO₄作用下, 利用吸电子基取代的芳磺酸芳基酯、芳磺酰氯通过C―S键断裂与酚的反应来制备邻位具有吸电子位阻官能团的二芳基醚; 此外, 在缺少相应酚的情况下, 上述的芳磺酸芳基酯在同样的条件下也可以得到相同的二芳基醚.     

双(甲基环戊二烯基)二芳氧基金属衍生物的合成和光谱

在碱存在下,双(甲基环戊二烯基)二氯化钛、锆和铪与取代酚反应合成了一系列双(甲基环戊二烯基)二芳氧基金属衍生物.它们与氢卤酸如HF,HCI,HBr和HI反应,形成相应的金属双(甲基环戊二烯基)二卤化物.讨论了金属电负性、苯环上取代基的电负性以及取代基的数目、位置对双(甲基环戊二烯基)二芳氧基金属衍生物中环戊二烯基环质子化学位移的影响.探讨了这些金属衍生物的红外吸收峰的归属.     

手性磷酸催化亚甲胺叶立德与吲哚-3-甲醇不对称[3+3]环加成反应:一步构建多取代四氢-β-咔啉

研究了手性磷酸催化醛、氨基丙二酸酯与3-吲哚基苯基取代甲醇的三组分不对称[3+3]环加成反应,立体选择性地一步构建多取代四氢-β-咔啉骨架.考察了不同取代的手性磷酸催化剂、溶剂等因素对反应的影响,对芳环上不同位置具有不同性质取代基的底物进行了扩展,获得中等到优秀的产率(70%～91%),对映选择性良好到优秀(80%～93%ee),反应对底物芳环上的吸电子基和给电子基都具有良好的容忍性.     

多聚磷酸催化的苄基芳基醚合成苄基酚的重排反应（英文）

系统研究了多聚磷酸(PPA)催化的苄基芳基醚的重排反应,有效调整吸电子基团(EWG)和供电子基团(EDG)在酚部分或苄基部分取代位置,有利于重排反应和重排的区域选择性.重排反应遵循芳环上的取代引导规则.这种容易实现的重排反应方法对于酚的苄基化具有实际应用价值.     

Cp2TiCl2催化下Grignard试剂与芳醛反应的研究

Meunier 等曾研究了 Cp_2TiCl_2催化下,格氏试剂对卤代烷和羰基化合物的还原反应,并报道了与芳环或碳-碳双键或碳-碳三键共轭的羰基化合物不被格氏试剂还原。我们却发现,在较低温度下,这些芳醛或与碳-碳重键共轭的羰基化合物也会被还原,特别是在芳环上有吸电子取代基时,还原产物的产率很高。     

3-乙基-2-丙基喹啉衍生物的合成工艺研究

以芳胺和正丁醛为原料,对甲基苯磺酸(TsOH)为促进剂,采用"一锅法"合成了3-乙基-2-丙基喹啉衍生物,系统地考察了原料比例、溶剂以及芳胺上取代基对反应的影响,比较了不同的质子酸促进剂对喹啉衍生物产率以及选择性的影响,并对产物进行了核磁共振表征.实验结果表明当用对甲基苯磺酸(TsOH)为促进剂时,3乙基-2-丙基喹啉收率可达到59%,同时生成40%N-丁基苯胺;磷钼酸、浓硫酸也可以选择性地得到喹啉衍生物,但收率较低,分别只有28%和24%.同时,考察了苯胺环上取代基对喹啉收率的影响,当苯环上有供电子基时,有利于喹啉的生成,而吸电子基则不利于喹啉的生成.并推测了反应机理.     

超声辐射下水介质中一锅合成3-甲基-4-芳亚甲基-异噁唑-5(4H)-酮

报道了室温超声辐射下, 水相中通过乙酰乙酸甲酯、盐酸羟胺和芳香醛的三组分一锅反应, 合成了一系列3-甲基-4-芳亚甲基-异噁唑-5(4H)-酮衍生物. 在超声波辐射下, 参与反应的醛无论芳环上连有吸电子基或供电子基, 该一锅反应在室温下都能较好地进行; 对于α,β-不饱和醛、杂环芳醛以及二元芳醛与乙酰乙酸甲酯、盐酸羟胺的一锅反应也能在室温下顺利进行, 获得中等以上的收率. 产物的结构通过元素分析, IR, 1H NMR及单晶解析表征. 该方法具有操作简单和环境友好等优点.     

三溴甲基芳烃合成新方法的研究

报道了一种以三氯甲基芳烃与三溴化硼反应制备系列三溴甲基芳烃的新方法. 该方法反应条件温和, 收率高, 选择性好. 同时, 对影响该反应的因素进行了研究, 发现当芳环上连有强吸电子基团时, 不利于反应的进行, 而连有推电子基团时, 则有利于反应进行; 当取代基处于邻位时, 则明显阻碍反应的进行. 采用这种方法已合成了十多个三溴甲基芳烃, 其中1个是未见文献报道的新化合物.     

氯磷酸二苯酯介入的芳香醛与砜缩合制备非对称芳香炔烃

氯磷酸二苯酯促进芳香醛与砜缩合反应在室温下有效进行,能高收率形成对应的非对称芳香炔烃.考察了醛及砜芳环上取代基对反应的影响,结果表明不论是吸电子基还是给电子基对反应都无明显影响,制备了一系列官能团化的非对称二苯基炔烃、噻吩及吡啶类炔烃、香豆素类炔烃及二苯基膦酰基保护的二炔烃和三炔烃,并从分子结构上阐明了本缩合反应可在室温下有效进行的原理.     

13C and 1H NMR of 2,6-diaryl-1-hydroxy piperidin-4-one oximes; substituent effects on cis/trans ratio and conformational equilibria

The reaction of substituted diarylidene acetones with hydroxylamine hydrochloride affords isomeric N-hydroxy diaryl piperidinone oximes as main products. The structures as well as conformational equilibria of these products were established by 1H and 13C NMR spectroscopy and further studied by variable temperature NMR. It was found that the cis/trans ratio of 2,6-substituted piperidine derivatives depended on the position of the substituent on the aromatic ring.     

Inhibiting activity of isocamphyl substituted phenols and their mixtures with 2,6-di-<Emphasis Type="Italic">tert</Emphasis>-butylphenol in the initiated oxidation of ethylbenzene

The stoichiometric coefficients of inhibition and rate constants for the reaction of several terpenephenols (isocamphyl substituted phenols) with ethylbenzene peroxy radicals were measured. Their reactivity was found to increase as the number of alkyl substituents grew and decreased with an o-alkoxyl compared with o-alkyl substituent because of the formation of an intramolecular H-bond. In spite of similar antiradical activities of terpenephenols with isocamphyl and isobornyl substituents, the reactivities of phenoxyl radicals formed from them in the interaction with sterically hindered phenol molecules are substantially different. They are higher for isocamphylphenols with substituents turned with respect to the aromatic ring plane.     

Structures and Properties of Molecular Torsion Balances to Decipher the Nature of Substituent Effects on the Aromatic Edge‐to‐Face Interaction

Various recent computational studies initiated this systematic re‐investigation of substituent effects on aromatic edge‐to‐face interactions. Five series of Tröger base derived molecular torsion balances (MTBs), initially introduced by Wilcox and co‐workers, showing an aromatic edge‐to‐face interaction in the folded, but not in the unfolded form, were synthesized. A fluorine atom or a trifluoromethyl group was introduced onto the edge ring in ortho‐, meta‐, and para‐positions to the C?H group interacting with the face component. The substituents on the face component were varied from electron‐donating to electron‐withdrawing. Extensive X‐ray crystallographic data allowed for a discussion on the conformational behavior of the torsional balances in the solid state. While most systems adopt the folded conformation, some were found to form supramolecular intercalative dimers, lacking the intramolecular edge‐to‐face interaction, which is compensated by the gain of aromatic π‐stacking interactions between four aryl rings of the two molecular components. This dimerization does not take place in solution. The folding free enthalpy ΔG_fold of all torsion balances was determined by ¹H NMR measurements by using 10 mM solutions of samples in CDCl₃ and C₆D₆. Only the ΔG_fold values of balances bearing an edge‐ring substituent in ortho‐position to the interacting C?H show a steep linear correlation with the Hammett parameter (σ_meta) of the face‐component substituent. Thermodynamic analysis using van′t Hoff plots revealed that the interaction is enthalpy‐driven. The ΔG_fold values of the balances, in addition to partial charge calculations, suggest that increasing the polarization of the interacting C?H group makes a favorable contribution to the edge‐to‐face interaction. The largest contribution, however, seems to originate from local direct interactions between the substituent in ortho‐position to the edge‐ring C?H and the substituted face ring.     

Pyrido-annellated diazaphospholenes and phospholenium ions

Pyrido-annulated 1,3,2-diazaphospholenium ions and P-bis(trimethylsilyl)amino substituted 1,3,2-diazaphospholenes were synthesised and characterised by spectroscopic methods and single-crystal X-ray diffraction studies. The distribution of bond distances provided evidence for pi-electron delocalisation in the fused ring system. This hypothesis was confirmed by calculations of magnetic (NICS, nucleus independent chemical shift) and geometrical (Bird index, bond shortening index) aromaticity indexes which attest aromatic character of the five-membered rings in the cations that is lost upon introduction of a substituent at the phosphorus atom. Computation of isodesmic reaction energies suggest that the reclamation of aromatic stabilisation energies in the products facilitates reaction of P-amino-subsituted annulated diazaphospholenes under cleavage of the fused ring system.     

硼酸与甲阶酚醛树脂的配位反应及配合物的结构

本文通过对溶液pH值的测定和外光谱分析，研究了硼酸与甲阶酚醛树脂的配位反应。结果表明：在室温下硼酸能与甲阶酚醛树脂中的羟基发生配位反应，并产生H^ 使溶液的pH值降低；溶液的酸性强弱与甲阶酚醛树脂中的羟甲基含量和硼酸的用量有关；硼酸以硼酸根离子的形式与树脂中的酚羟基和邻位羟甲基发生配位反应，形成了一个含有两个氧原子和一个硼原子的六元环，使甲阶酚醛树脂发生交联。     

Synthesis,Characterization and Investigation of Side Chain Length and/or Substituents Effect on the Liquid Crystal Properties of New Mesogens

New substituted and unsubstituted phenol based mesogene series having an azo central linkage was synthesized by fixing phenol as rigid core unit with aromatic amine. The terminal –OH group was esterified successively by long alkyl chain acid chloride of variable length (n=2, 6, 11, 15, 17). All 25 synthesized compounds exhibit mesomorphism. The effect of side chain length and substituents on the stability of liquid crystals was studied. The study reveals that nitro substituent destabilizes nematic and smectic phases more than floro substituent. Furthermore, the transition temperature decreases as the length of side chain increases.     

Substituent effects on the photocycloaddition reactions of phenol to benzonitriles

Methoxy-, methyl-, and chloro-substituted benzonitriles undergo photocycloaddition to phenol to give substituted 1,2-dihydroazocin-2-ones III , by initial attack of the cyano group on the aromatic ring of the phenol. The efficiency of the photocycloaddition reaction varied with the position of the substituents, with the para-substituted ones giving the largest amount of photoproduct.     

Tuning the reactivity and chemoselectivity of electron-poor pyrroles as dienophiles in cycloadditions with electron-rich dienes

Activation by Lewis acid catalysis and high pressure allows pyrrole derivatives to react with electron-rich dienes in normal electron demand [4+2] cycloadditions, provided that the aromatic ring is substituted by at least two electron-withdrawing groups. The dienophilic behavior of the heterocycle is expressed through the involvement of either the aromatic carbon-carbon double bond in an all-carbon process or the carbonyl moiety of the substituent in a heterocycloaddition reaction. In this regard, the nature of the heterocyclic substituents is shown to have a dramatic influence and to direct both the reactivity and the chemoselectivity of the cycloaddition.     

茂钛类络合物催化碳酸二甲酯和苯酚酯交换反应合成碳酸二苯酯的研究

首次将二氯二茂钛用于碳酸二甲酯和苯酚酯交换合成碳酸二苯酯的反应, 发现二氯二茂钛对该反应来讲是一种性能优良的催化剂; 和钛酸酯类催化剂相比, 茂钛类催化剂在空气中更稳定, 从而更适合于工业化应用. 同时探讨了不同种类茂钛类化合物的催化性能, 发现位阻效应、环戊二烯环的电子分散效应以及取代基的吸电子效应等, 都会影响中心钛原子的Lewis酸性以及相应的催化活性. 总体来讲, 位阻效应越小、环戊二烯环的电子分散效应越大、与中心钛原子连接的取代基的吸电子能力越强, 越有利于反应的进行.     

Stacking interactions between nitrogen-containing six-membered heterocyclic aromatic rings and substituted benzene: studies in solution and in the solid state

The stacking interactions between an aromatic ring and a pyridine or a pyrimidine ring are studied by using a series of triptycene-derived scaffolds. The indicative ratios of the syn and anti conformers were determined by variable-temperature NMR spectroscopy. The syn conformer aligns the attached aromatic ring and the heterocycle in a parallel-displaced orientation while the anti conformer sets the two rings apart from each other. Comparing to the corresponding control compounds where a benzene ring is in the position of the heterocycle, higher attractive interactions are observed as indicated by the higher syn/anti ratios. In general, the attractive interactions are much less sensitive to the substituent effects than the corresponding nonheterocycles. The greatest attractive interactions were observed between a pyrimidine ring and a N,N-dimethylaminobenzene, consistent with a predominant donor-acceptor interaction. The interactions between a pyridine ring and a substituted benzene ring show that the pyridine is comparable to that of a NO2- or a CN-substituted benzene ring except for the unpredictable substituent effects.