Photoreactions of Aromatic Compounds. XXXVII.1 Photosubstitution Reactions of Nitronaphthalene Derivatives

A systematic investigation was made of the photochemical properties of 12 fluoronitronaphthalenes and some methoxynitronaphthalenes in the presence of hydroxide ions, methoxide ions and methylamine. Results show that photosubstitution of fluorine in fluoronitronaphthalenes by methoxide or hydroxide must be a consequence of the activating effect of the nitro group. This effect is also clearly present when the nitro group and the fluorine atom are in different rings.     

Threading Cyclodextrins in Chloroform: A [2]Pseudorotaxane

The unusual self-assembly in chloroform of a novel cyclodextrin-based [2]pseudorotaxane, composed of heptakis-2,6-di-O-methyl-3-O-acetyl-β-cyclodextrin and a viologen-containing linear component, is reported.     

4H-[1]苯并吡喃[3,4-d]异噁唑-4-酮的合成(英文)

芳酰乙酸乙酯在乙氧基镁的作用下与取代的苯甲酰氯反应生成2-取代苯并吡喃酮。2-取代苯并吡喃酮和盐酸羟胺经Beckmann重排反应合成了4H-[1]苯并吡喃[3,4-d]异噁唑-4-酮。X衍射谱图表明,反应过程中表现区域选择性。对该反应的反应机理进行了初探。     

Syntheses and Properties of Aromatic Polyimides Based on 1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane and 1,1-Bis[4-(4-aminophenoxy)phenyl]-1-phenylethane

A series of fluorinated polyimides were prepared from 1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane with various aromatic tetracarboxylic dianhydrides via a conventional two-step procedure. These polyimides were amorphous in nature and afforded flexible and tough films. Some polyimides derived from less stiff dianhydrides were soluble in polar organic solvents. The glass-transition temperatures (T _g) of these polyimides ranged from 252 to 324C, and softening temperatures (T _s) stayed in the 254322C range. Decomposition temperatures (T _d) at 10% weight loss all occurred above 569C in both air and nitrogen atmospheres. For a comparative study, another series of analogous polyimides based on 1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenylethane were also pepared and characterized.     

芳香亲核取代氢反应及4-氨基二苯胺的合成

芳香亲核取代氢反应是一种环境友好的有机合成反应。4-氨基二苯胺是一种重要的工业中间体,在它的合成过程中对环境污染严重。Flexsys公司将芳香亲核取代氢反应应用于4-氨基二苯胺的合成,解决了环境污染问题。并因此荣获1998年度美国总统绿色化学挑战奖。本文介绍了4-氨基二苯胺的传统合成方法,进而又介绍了芳香亲核取代氢反应的机理及其在4-氨基二苯胺合成中的应用。     

［Emim］HSO4-AlCl3催化1-丁烯齐聚

制备Brnsted-Lewis双酸性离子液体催化剂［Emim］HSO4-AlCl3,并用于催化1-丁烯齐聚反应,考察催化剂用量、反应压力、反应温度和反应时间对1-丁烯齐聚产物选择性的影响。结果表明,强酸性离子液体催化1-丁烯齐聚反应得到的产物主要为四聚体。在n(AlCl₃)∶n(［Emim］HSO₄)=1∶1、催化剂用量2.5 g、反应温度30 ℃、反应压力0.08 MPa和反应时间1.0 h条件下进行齐聚反应,产物选择性和反应体系的稳定性较理想。     

Organosoluble and Light-colored Fluorinated Polyimides from 2,2-Bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]sulfone and Aromatic Dianhydrides

A new trifluoromethyl-substituted diamine monomer, 2,2-bis[4-(4-amino-2-trifluoromethylpenoxy)phenyl]sulfone (II), was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 4,4’-sulfonyl diphenol in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Novel fluorinated polyimides V_a–f having inherent viscosities ranging from 0.74 to 1.14 dL/g were synthesized from the diamine II with various aromatic dianhydrides via thermal imidization of poly(amic acid). Most of V series were soluble in the all test solvents, except V_b(H). These polyimide films had strengths at yield of 94–119 MPa, tensile strengths of 90–118 MPa, elongations to break of 10–16%, and initial moduli of 2.0–2.4 GPa. The glass transition temperature (T_g) of these polymers were in the range of 244–297 ^○C, their 10% weight loss temperatures were above 520 ^○C under ether nitrogen or air atmosphere, and left more than 45 wt% residue even at 800 ^○C in nitrogen. Compared with polyimides VII based on 4,4’-bis(3-aminophenoxy)diphenyl sulfone (II’), V showed better solubility and lower color intensity, dielectric constant, and moisture absorption. Their films had cutoff wavelengths between 355–402 nm, b^* values ranging from 6.8 to 32.9, dielectric constants of 3.32–4.27 (1 MHz), and moisture absorptions in the range of 0.27–0.62 wt%.     

Tetrapyrazolyl-calix[4]arene-based supramolecular architectures from [Pd16L4] macrocycle to three-dimensional microporous channels

By employing di-palladium complex [(bpy)₂Pd₂(NO₃)₂](NO₃)₂ (where bpy = 2, 2′-bipyridine) as corners and tetrapyrazolate calix[4]arene-based ligand (L^4 −) as linkers, a novel cavity-containing high-positively-charged polypyrazolate-bridged metallo-macrocycle [Pd₁₆L₄]^16 +·16NO₃ with Pd(II)⋯Pd(II) dimetal-coordination motifs has been synthesized by a directed coordination driven self-assembly with spontaneous deprotonation of the 1H-bipyrazole ligands in aqueous solution. The counter ions NO₃⁻ were trapped within the amphiphilic 3-D microporous channels in the solid state.     

离子液体中TS-1分子筛催化环己烷氧化反应

以离子液体[emim]BF4为反应介质,叔丁基过氧化氢(TBHP)为氧化剂,TS-1分子筛为催化剂,进行了环己烷选择性氧化反应研究.考察了氧化剂与环己烷物质的量比、反应时间、反应温度及离子液体/催化剂体系循环使用对环己烷氧化反应的影响.实验结果表明,在TBHP/环己烷物质的量比为2,反应温度为90 ℃,反应时间为18 h时,环己烷的转化率为13.2%,目的产物环己酮与环己醇的选择率高达97.6%.离子液体/催化剂体系循环使用4次后环己烷的转化率及氧化产物的收率略有降低.     

(1S,4S)-2-甲基-2,5-二氮杂二环[2.2.1]庚烷的合成

以N—位磺酰化的反—4—羟基—L—脯氨酸为原料,以硼氢化钾与氯化锌还原羧基,以三乙胺和丙酮代替吡啶进行羟基磺酰化和羟基氯代反应,“一锅煮”进行取代环合和去N—磺酰化合成(1S,4S)—2—甲基—2,5—二氮杂二环[2．2．1]庚烷,总收率达53％。该法操作简便,收率高,更有利于工业化生产。     

Anion complexation by calix[4]arene-TTF conjugates

Calix[4]arenes bearing tetrathiafulvalene (TTF) moieties appended to the upper rim via the amidic functions were synthesized and used for ¹H NMR and UV/Vis complexation studies towards selected anions. It was found that the complexation affinity towards H₂PO₄⁻ dramatically depends on the substitution pattern of the calixarene moiety. As a result, the proximally disubstituted derivative has a complexation constant by two orders of magnitude higher than the distally disubstituted analogue. The differences between proximal and distal receptors were also documented by their behaviour during the oxidation of the attached TTF units.     

Gold(I)‐Catalyzed [4+2] Annelation/Nucleophilic Addition Sequence: Stereoselective Synthesis of Functionalized Bicyclo[4.3.0]nonenes

The gold(I)‐catalyzed isomerization of readily available 1,8‐dien‐4‐ynes allows the rapid construction of a variety of synthetically useful bicyclo[4.3.0]nonenes by a stereoselective sequence involving a [4+2] annelation/nucleophilic addition process.     

1-甲基-1H-苯并咪唑-4-硼酸的合成

以1-溴-3-氟-2-硝基苯为原料,经甲胺取代,锌粉还原,甲酸环化3步反应合成4-溴-1-甲基-1H-苯并咪唑,再与频哪醇硼酸酯在双(三环己基膦)二氯化钯催化下进行硼酸化,制得未见文献报道的目标化合物1-甲基-1H-苯并咪唑-4-硼酸,4步反应总收率27.4%。产品经MS和1H NMR确证。该合成工艺具有反应条件温和、操作简单的优点。     

Stability Constants of Oximes of 4-Substituted-2-acetylphenols [1]

Proton-ligand stability constants (pKd) and metal-ligand stability constants for six oximes of 4-substituted-2-acetyl phenol in H₂O: Dioxane (1:3) are obtained by the spectrophotometric method of Magnusson et al. as modified by Patel et al.     

Nitriles in heterocyclic synthesis: Synthesis of pyrazolo[1, 5-a] pyrimidine,pyrazolo[1, 5-c][1, 2, 4]triazine and pyrazolo[4, 3-e][1, 2, 4]triazine derivatives

5-Amino-3-phenylpyrazole ( 1 ) reacted with enaminonitriles 2a – c to afford the pyrazolopyrimidines 5a , b and the 5-substituted aminopyrazole 8 . 5a reacted with arenediazonium chlorides and benzaldehyde to give 6 and 7 respectively. Also, o-hydroxyacetophenone afforded the fused pyrazole derivative 9 on treatment with 1 . Enaminonitrile 3 coupled with 11 and arenediazonium chlorides to give 12 and 13 respectively. Cyclization of 13a , b afforded the pyrazolotriazines 15a , b .     

[emim]BF4离子液体催化酯化反应研究

研究了环境友好的[emim]BF4离子液体催化亚油酸等高碳脂肪酸与无水乙醇酯化反应,考察了亚油酸与乙醇的摩尔比、反应温度、离子液体用量等条件对亚油酸酯化反应结果的影响,优化了反应的工艺条件.适宜的反应条件为n(乙醇)n(亚油酸)=41,回流反应温度,[emim]BF4用量为反应物质量的42%.结果表明[emim]BF4离子液体对亚油酸等脂肪酸的酯化反应显示了优异的催化活性,亚油酸酯化率最高可达94%.反应产物与离子液体易于分离,离子液体循环使用5次以上,酯化率没有明显降低.