1,4-二氮杂双环[2.2.2]辛烷催化的有机化学反应

综述了有机小分子催化剂1,4-二氮杂双环[2.2.2]辛烷(DABCO)在有机合成反应中的应用与发展。这种有机小分子催化的反应大多数条件温和、操作简单;相对过渡金属而言,对环境友好;在一定条件下,这种催化剂可以回收再利用。     

基于[3+2]环加成反应的氮杂螺[3,4]环辛烷的合成

哌嗪、吗啉是小分子药物中常见的结构片段,2,6-二氮杂螺[3,4]环辛烷和2-氧-6-氮杂螺[3,4]环辛烷等四元螺环化合物作为其类似物,在药物化学领域具有良好的应用前景.本研究以廉价易得的丙二酸二乙酯或丙烯酸乙酯为起始原料,经[3+2]环加成反应,可便捷高效地完成6-苄基-2,6-二氮杂螺[3,4]环辛烷和2-氧-6-氮杂螺[3,4]环辛烷克级水平的合成.     

3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐的合成

以己二酸为初始原料,依次经酰氯化,溴代,苄胺环合,水解,还原,脱水环合,氢解脱苄和成盐等8步反应,合成了3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐,总收率23%,纯度100%,其结构经1H NMR确证。     

1，4-二氮杂二环[2.2.2]辛烷-1，4-二乙酸配合物的合成、结构与磁性

合成了{[M(L)₂(H₂O)₂](ClO₄)₂·4H₂O}_n(M=Cu 1,Co 2;L=1,4-二氮杂二环[2.2.2]辛烷-1,4-二乙酸),并进行了元素分析、红外、热重、变温磁化率等表征。单晶结构表明这2个配合物属于单斜晶系,P2₁/c空间群。Cu(Ⅱ)和     

氮杂环丙烷[3+3]环加成反应研究进展

氮杂环丙烷作为一类具有生物活性的三元杂环化合物,由于其三元环高度的环张力而被广泛应用于[2+2]、 [3+1]、 [3+2]、 [3+3]、 [4+3]以及[5+2]等环加成反应中,近年来受到了研究学者们的广泛关注。本文主要综述了氮杂环丙烷与含C=C、 C=N、 C≡N、 C≡C、 C═•═C以及其它类化合物的[3+3]环加成反应的研究进展,并对其未来研究方向进行了展望。      

杂环光化学IV.1,2,4-三氮杂-双环[4.2.0]辛烷衍生物的光化学合成

通过1,3-二甲基-6-氮杂胸腺嘧啶与含极性取代基的烯类化合物的光环合加成反应,合成了1,2,4-三氮杂-2,4,6-三甲基-3,5-二氧-8-乙酰基-双环[4.2.0]辛烷的三个差异构体(6R,8S)-1a,(6S,8R)-2a和(6R,8R)-3a;1,2,4-三氮杂-2,4,6-三甲基-3,5-二氧-8-氰基-双环[4.2.0]辛烷的两个差相异构体(6S,8R)-2b和(6R,8R)-3b以及1,2,4-三氮杂-2,4,6-三甲基-3,5-二氧-8-羧甲酯基的两个差相异构体.讨论了该反应的区域选择性,以及产物的立体化学。     

1-氮杂-2,8-二氧杂二环[3.3.0]-辛烷类化合物合成的新方法

以苯基-3,5-二(甲氧基羰基)-2-异(口恶)唑啉-N-氧化物为偶极体,丙烯酸乙酯为亲偶极体,通过[3+2]环加成反应,简便地合成了含有多官能团的1-氮杂-2,8-二氧杂二环[3.3.0]-辛烷类化合物。该反应条件温和,产率较高(50%～93%).化合物的结构经元素分析,¹H NMR,¹³C NMR,IR和MS确认和表证,并对其波谱性质进行了讨论。     

含手性侧链结构的1, 5-二氮环辛烷的合成

手性α-氨基醇和原氯乙酸三乙酯作用,可同时分离得到两种手性侧链：酰胺醇(2a,2b)和恶唑啉(2c,2d);分别和1,5-二氮环辛烷反应,生成带手性侧臂的1,5-二氮环辛烷化合物(1a～1d),其结构经红外、核磁、质谱和元素分析等得到了证实。     

2,6-二氧杂双环[3.2.1]辛烷类衍生物的串联合成

以2-甲基-4-戊烯-1,2-二醇和芳香醛为原料, 三氯化铟为催化剂, 得到了一系列1,3-二取代2,6-二氧杂双环[3.2.1]辛烷类衍生物. 整个反应采用一锅法, 反应条件简单且产率高. 所有的化合物均用¹H NMR, ¹³C NMR和质谱法进行了表征, 并用NOESY确立了分子的相对构型.     

1-氯甲基-4-氟-1,4-二氮杂双环[2.2.2]辛烷二(四氟硼酸盐)氧化二苯二硒醚:烯烃的苯硒化方法

在三氟甲磺酸银的催化下,二苯二硒醚被1-氯甲基-4-氟-1,4-二氮杂双环[2.2.2]辛烷二(四氟硼酸盐)(Selectfluor)氧化后,分别与1-己烯烃、苯乙烯或其衍生物加成;在含有水或醇(如甲醇、乙醇、异丙醇)的二氯甲烷中(二氯甲烷与水或醇的体积比为1∶1)反应,分别得到β-羟基或β-烷氧基苯硒醚,产率为72%~94%;探讨了反应条件及底物的适用范围。此方法具有反应条件温和、产率高的特点。     

Thermal behaviour of some dibenzobicyclo[2.2.2]octane derivatives

A number of dibenzobicyclo[2.2.2]octane derivatives have been studied due to the interest of such compounds as ligands for coordination compounds with potential biological activity. Their thermal behaviour has been analyzed in order to find out more information about their fragmentation. A connection between the bridge substituents and the fragmentation process has been observed.     

Synthesis and characterization of poly(benzazoles) containing the bicyclo[2.2.2]octane moiety

Poly(benzobisoxazoles) (PBOs), poly(benzobisthiazoles) (PBTs) and copolymers thereof containing the 2,5-dihydroxybicyclo[2.2.2]octane moiety have been prepared and studied. The homopolymers were synthesized by the polycondensation of 2,5-dihydroxybicyclo[2.2.2]octane-1,4-dicarboxylic acid with 4,6-diamino-1,3-benzenediol dihydrochloride or 2,5-diamino-1,4-benzenedithiol dihydrochloride in poly(phosphoric acid). Random and block copolymers (PBO–PBT) were also prepared. The polymers were characterized by solubility, X-ray diffraction, spectroscopy (infrared and solid-state ¹³C nuclear magnetic resonance), and thermal analysis such as differential scanning calorimetry and thermogravimetric analysis. Thermogravimetric analysis showed thermal stability of the polymers above 375°C in air and under argon atmosphere. The polymers exhibited high resistance to organic and inorganic solvents. The polymers were converted to the more stable aromatic polymers via dehydration and retro Diels–Alder reactions of the 2,5-dihydroxybicyclo[2.2.2]octyl moiety by pyrolysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 277–281, 1998     

Organic reactions catalyzed by 1, 4-diazabicyclo [2.2.2] octane (DABCO)

The organic reactions catalyzed by 1, 4-diazabicyclo [2.2.2] octane (DABCO) are reviewed. Most of the reactions start conveniently from available substrate and proceed under mild conditions. The reactions are environmentally friendly and the catalyst can be recycled in some cases. The perspectives on DABCO-catalyzed reactions are pointed out. __________ Translated from Chemistry online, 2007, 70(10): 759–765 [译自: 化学通报]     

Synthesis,characterization, and properties of colorless rigid-rod poly(benzobisthiazole) derived from bicyclo[2.2.2]octane

Polycondensation in polyphosphoric acid of 2,5-diamino-1,4-benzene dithiol dihydrochloride with bicyclo[2.2.2]octane-1,4-dicarboxylic acid, as well as the corresponding dimethyl ester or diacid chloride, led to rigid-rod benzobisthiazole polymers. Colorless and soluble polymers with intrinsic viscosities as high as 30.6 dL/g (methanesulfonic acid, 30°C) were obtained. The ultraviolet-visible spectrum of a polymer film cast from methanesulfonic acid under reduced pressure displayed no absorptions in the visible range (400–900 °m). The polymer was thermooxidatively stable up to 420°C in air as determined by thermogravimetric analysis. Fibers spun from a lyotropic polyphosphoric acid solution exhibited a tensile strength of 300–450 Ksi, a modulus of 26 Msi, and a compressive strength of 53 Ksi. Wide-angle X-ray scattering patterns of polymer fibers indicated a 3-dimensional crystal structure rather than a nematic liquid crystal structure. © 1994 John Wiley & Sons, Inc.     

An unexpected palladium-catalyzed cyclization of bis-hydroxy allylic alcohols to dioxabicyclo[2.2.2]octanes

The palladium(II)-catalyzed cyclization of bis-hydroxy allylic alcohols afforded quantitatively a mixture of (3-alkyl-5-vinyltetrahydrofuran-3-yl)methanol and 4-alkyl-1-methyl-2,6-dioxabicyclo[2.2.2]octane.     

Cubane,Bicyclo[1.1.1]pentane and Bicyclo[2.2.2]octane: Impact and Thermal Sensitiveness of Carboxyl-, Hydroxymethyl- and Iodo-substituents

With the burgeoning interest in cage motifs for bioactive molecule discovery, and the recent disclosure of 1,4-cubane-dicarboxylic acid impact sensitivity, more research into the safety profiles of cage scaffolds is required. Therefore, the impact sensitivity and thermal decomposition behavior of judiciously selected starting materials and synthetic intermediates of cubane, bicyclo[1.1.1]pentane (BCP), and bicyclo[2.2.2]octane (BCO) were evaluated via hammer test and sealed cell differential scanning calorimetry, respectively. Iodo-substituted systems were found to be more impact sensitive, whereas hydroxymethyl substitution led to more rapid thermodecomposition. Cubane was more likely to be impact sensitive with these substituents, followed by BCP, whereas all BCOs were unresponsive. The majority of derivatives were placed substantially above Yoshida thresholds—a computational indicator of sensitivity.     

Above Room Temperature Organic Dielectric Switchable Material: Diprotonated 1,4‐Diazabicyclo[2.2.2]octane Shifts between Two Pyruvic Acids

A pure organic single crystal, [H₂dabco] · [PA]₂ ([H₂dabco]²⁺ = diprotonated 1,4‐diazabicyclo‐[2.2.2]octane, PA = pyruvic acid), was synthesized and its dielectric property was studied. [H₂dabco] · [PA]₂ owns a distinctive architecture composed of discrete hydrogen‐bonded trimeric units, of which one [H₂dabco]²⁺ cation bridged by two PA^– anions through N–H ··· O hydrogen bonding. The switchable property around 348 K was revealed by crystal structure studies between low and high dielectric states. In the high temperature phase, the [H₂dabco]²⁺ cation presents itself in a rotationally disordered state and lies at the symmetric center of the trimer. In the room temperature phase, it is frozen in an ordered state and shifts toward a PA^– anion at one end along the hydrogen bond.     

4-Aminobicyclo[2.2.2]octanone Derivatives with Antiprotozoal Activities

Summary.  4-Aminobicyclo[2.2.2]octanones which were prepared in one-pot-reactions from benzylidene acetone and dialkylammonium rhodanides were reduced stereoselectively to their corresponding alcohols. The activities of the bicyclic compounds against causative organisms of tropical deseases were examined. The 4-aminobicyclo[2.2.2]octan-2-ols were in general more active against Trypanosoma b. rhodesiense and Plasmodium falciparum than the corresponding keto compounds. Corresponding author. E-mail: robert.weis@uni-graz.at Received November 27, 2002; accepted December 2, 2002 Published online May 2, 2003     

Synthesis of molecular motors incorporating para-phenylene-conjugated or bicyclo[2.2.2]octane-insulated electroactive groups

The insulating role of the bicyclo[2.2.2]octane fragment has been theoretically evaluated by comparing the electronic coupling parameter (V(ab)) in 1,4-bis(ferrocenyl)benzene (1) and 1,4-bis(ferrocenyl)bicyclo[2.2.2]octane (2). The geometries were optimized by DFT and an extended Hückel calculation was performed to evaluate V(ab) by the dimer splitting method. The calculations showed a 12-fold decrease of the electronic coupling from 60 meV for 1 to 5 meV for 2. The second part describes the synthesis of two potential molecular motors with one incorporating the insulating bicyclo[2.2.2]octane fragment. These molecules are based on a ruthenium complex bearing a tripodal stator functionalized to be anchored onto surfaces. The ferrocenyl electroactive groups and the cyclopentadienyl (Cp) rotor are connected through a p-phenylene spacer (5) or through a spacer incorporating an insulating bicyclo[2.2.2]octane moiety (6).