有机催化的串联反应合成螺环氧化吲哚研究进展

本文对有机催化的不对称串联反应在三元及四元螺环氧化吲哚类化合物合成中的应用进展进行了综述。近年来,有机催化的串联反应被广泛的应用于具有多环骨架的复杂分子的合成中。螺环氧化吲哚骨架是一类广泛存在于天然产物及活性分子中的优势生物碱骨架。因此,通过有机催化的不对称串联反应合成螺环氧化吲哚类化合物一直是有机化学领域研究的热点。     

手性螺环氧化吲哚类化合物的设计、合成及抗肿瘤活性研究

前期利用[2+1]环化反应合成了一系列手性螺环氧化吲哚类化合物,研究采用MTT法对这些化合物在结肠癌细胞CT26和宫颈癌细胞Hela中的抗肿瘤活性进行了评价,探析其构效关系,并在苗头化合物的基础上进行了结构优化设计合成了目标化合物,并再次评价其抗肿瘤效果。结果显示,27个手性螺环氧化吲哚-环丙烷-茚二酮类化合物对CT26和Hela细胞均具有良好的抗增殖作用。其中,16个化合物对CT26细胞的抑制活性优于阳性对照顺铂,14个化合物对Hela细胞的抗增殖能力与顺铂相当或更优。进一步,结构优化得到的化合物均能有效抑制CT26和Hela细胞的增殖,部分手性螺环氧化吲哚类目标化合物可作为抗肿瘤药物候选先导化合物,具有较好的研发潜力。     

氧化重排法合成2-吲哚酮和2,2'-吲哚啉螺环化合物的研究进展

综述了国内外氧化重排法合成系列2-吲哚螺环化合物和2,2'-吲哚啉螺环化合物的研究进展。     

1,3-偶极子参与不对称构建氧化吲哚C(3)位五元螺环化合物的研究进展

螺环氧化吲哚化合物广泛存在于天然产物中,具有抗肿瘤、抗菌、抗微生物和抗炎等诸多生物活性,常作为先导化合物用于新药发现。因其结构复杂,具有多个立体中心,合成过程中立体选择性难以控制,因此含该类骨架化合物的不对称合成是研究者的关注热点。以1,3-偶极子为底物,不对称[3+2]环加成反应是构建手性五元螺环氧化吲哚化合物的重要方法。按1,3-偶极子进行分类,对近年来该类化合物的不对称构建方法进行综述,为该类化合物的合成提供参考。     

二烯酮类化合物在构建复杂有机化合物中的应用

二烯酮作为一类具有多个化学反应位点的不饱和酮类化合物,可与多种反应底物实现不同类型的化学转化,高效快捷地构建功能各异的有机化合物。该文综述了近些年二烯酮类化合物与多种反应底物的化学转化。首先,探讨了2,5-环己烯酮类化合物与不同试剂的串联Michael-Smiles环丙烷化反应、环加成反应、三组分Ritter反应、光化学重排反应和氧化偶联反应分别构建了环丙烷类衍生物、氮杂螺环类衍生物、含氟烷基N,O-缩酮类衍生物、稠环吲哚类化合物、酰胺类化合物和不对称联芳烃类化合物。接着,分析了1,4-戊二烯-3-酮类化合物与丙二腈(硝基甲烷)、硫氢化钠、氧化吲哚、吡唑酮、芴和巴比妥酸双Michael加成反应,分别合成了多取代环己酮类化合物、二芳基噻喃酮类化合物、螺环氧化吲哚类化合物、螺环吡唑酮类化合物、螺环芴类化合物和螺环巴比妥类衍生物。然后,介绍了2,4-戊二烯-1-酮类化合物的1,4-共轭加成、氮杂Michael加成反应、分子内Morita-Baylis-Hillman (MBH)反应、分子内还原Aldol反应、分子内Aldol反应和分子内[4+2]环加成/氧化反应分别实现了有机含硫化合物、有机含氮化合物、多取代茚酮类化合物和SGLT2抑制剂——托格列净关键中间体的制备。最后,对二烯酮在后续化学反应中的潜在应用进行了展望。     

C(2)位螺环氧化吲哚化合物合成研究进展

C(2)位螺环氧化吲哚化合物存在于许多天然生物碱和生物活性物质中,具有多种生物活性,由于结构新颖、独特且合成难度较大,因此该类化合物的合成引起了有机化学家和药物化学家的关注。在对近几年来氧化吲哚C(2)位螺环化合物合成方法调研的基础上,分别以过渡金属催化、高价碘试剂介导催化、有机催化、酸碱介导催化重排、光催化和其他催化等不同合成方法进行分类介绍该类化合物的研究进展,以期为该类化合物的后续研究提供参考。     

二烯酮类化合物在构建复杂有机化合物中的应用

二烯酮作为一类具有多个化学反应位点的不饱和酮类化合物,可与多种反应底物实现不同类型的化学转化,高效快捷地构建功能各异的有机化合物。该文综述了近些年二烯酮类化合物与多种反应底物的化学转化,首先探讨了2,5-环己烯酮类二烯酮与不同试剂的串联Michael-Smiles环丙烷化反应、环加成反应、三组分Ritter反应、光化学重排反应和氧化偶联反应分别构建了环丙烷类衍生物、含氟烷基N,O-缩酮类衍生物、稠环吲哚类化合物、酰胺类化合物和不对称的联芳烃类化合物,接着分析了1,4-戊二烯-3-酮类二烯酮与丙二腈（硝基甲烷）、硫氢化钠、氧化吲哚、吡唑酮、芴和巴比妥酸双Michael加成反应,分别合成了多取代环己酮类化合物、二芳基噻喃酮类化合物、螺环氧化吲哚类化合物、螺环吡唑酮类化合物、螺环芴类化合物和螺环巴比妥类衍生物,然后研究了2,4-戊二烯-1-酮类二烯酮的1,4-共轭加成、氮杂Michael加成反应、分子内MBH反应、分子内还原Aldol反应、分子内Aldol反应和分子内[4+2]环加成/氧化反应分别实现了有机含硫化合物、有机含氮化合物、多取代茚酮类化合物和SGLT2抑制剂——托格列净关键中间体的制备,最后对二烯酮在后续化学反应中的潜在应用进行了展望。     

三氮唑螺氧化吲哚衍生物的合成及表征

以1-苄基-2-氧代吲哚-3-亚氨基甲酸叔丁脂和4-取代(Z)-N-苯基苯甲酰氯为底物通过1,3-偶极环加成反应合成了9种目标产物。通过比较目标产物的产率,对反应溶剂、碱及其用量、温度等因素进行了优化,确定了最佳反应条件,即在25℃下以二氯甲烷为溶剂、三乙胺为碱,且n(Et3N)∶n(1-苄基-2-氧代吲哚-3-亚氨基甲酸叔丁脂)=2.0∶1.0时,目标化合物最高产率可达94.4%。将具有生物活性的三氮唑骨架引入到螺环氧化吲哚骨架中,为更好地发现具有生物活性的该类新化合物提供借鉴。     

钯催化的3,3’-螺-2-吲哚酮的合成研究

以Pd（OAc）2为催化剂,三叔丁基膦为配体,以NaOt-Bu为碱,通过2-吲哚酮的分子内芳基化反应,以93%的收率合成得到3,3’-螺碳环-2-吲哚酮化合物。     

2-吲哚酮类化合物的研究进展

2-吲哚酮类化合物具有抗炎、抗精神病、抗癌、抗菌等生物活性,特别是其手性合成的螺吲哚酮类化合物的生物活性和药效研究是当前的研究热点。结合部分已上市和临床研究的药物,对近年来2-吲哚酮类化合物的衍生合成及其研究进展进行了综述。     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.