共查询到20条相似文献,搜索用时 140 毫秒
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聚乙醇酸及其与乳酸的共聚物是一类无毒、有良好的生物相容性和生物可降解材料,它们广泛地用作药物控释体系的载体,牙科植入材料[1,2].但由于聚乙醇酸的高度可结晶性,使其不溶于包括三氟乙酸在内的几乎所有的有机溶剂,因此通过共聚来改进其物化性质的研究一直方... 相似文献
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通过相转移催化关环反应合成了新的6-取代-2-疏-2-烷(芳)氧-4-(2,-4二氯苯基)-4-氢-1,3,2-苯并二氧磷杂环已烷(3a-3g),用结晶法分离得到7对非对联消旋体,其结构经1HNMR、31PNMR和元素分析确证,化合物3a-A单晶X射线分析表明其构型为(2R,4S;2S,4R).生物活性测定结果表明,化合物3C有良好的杀虫活性,非对映消旋体A和B具有协同杀虫作用. 相似文献
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通过相转移催化关环反应合成了新的6-取代-2-硫-2-烷(芳)氧-4(2,4-二氯苯基)-4-氢-1,3,2-苯并二氧磷杂环己烷(3a-3g),用结晶法分离得到了7对非对映消旋体,其结构经HNMR、^31PNMR和元素分析确证,化合物3a-A单晶X射线分析表明其构型为(2R,4S;2S,4R),生物活性测定结果表明,化合物3c有良好的杀虫活性,非对映消旋体A和B具有协同杀虫作用。 相似文献
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In the presence of pyridine, the Pd-catalyzed addition reaction of CO and CCI4 to 1-octene could be carried out smoothly under mild conditions. In this reaction, the satisfactory results were afforded when different alcohols and palladium catalysts were used. 相似文献
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Karl Grubmayr Ulrike Gabriella Wagner 《Monatshefte für Chemie / Chemical Monthly》1988,119(6-7):793-812
1H NMR-spectroscopic investigations of the acid catalyzed addition of methanol to dihydrodipyrrinones (Z)-2, (E)-2, and4 show the C-protonation of their enamide parts to be the first and rate determining step forming the key intermediate, the N-acyl-immonium ion N+. Its ability to add nucleophiles diastereoselectively can be used to prepare the adductsl-3 andl-5. Exclusive formation of thelike-isomer can be explained by a stereoelectronically favoured approach of the nucleophile and by the thermodynamically favoured arrangement of the bulky ring substituents. Both explanations are based on low temperature X-ray crystal structure determinations: in the first place, the orientation of the added nucleophile could be found to be nearly parallel to the -plane of the lactam unit and quasi-axial with respect to theenvelope-like conformation of the five-ring lactam; in the second place, the relative orientation of the methoxycarbonyl-metyl-group at C-3 and the pyrrolylmethyl-substituent at C-4 could be found to be atrans-quasi-diequatorial one. 相似文献
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H. D. Durst D. K. Rohrbaugh S. Munavalli 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2680-2696
Microwave-assisted reaction of dimethyl H-phosphonate with cyclohexene-, 1,2-butene-, and 1,2-decene oxides furnishes 8, 5, and 17 compounds, respectively. The probable mechanism of the formation of the various compounds via free radical reactions and their GC-MS characterization are presented in this article. 相似文献
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V. A. Mamedov A. A. Kalinin A. T. Gubaidullin I. A. Litvinov Ya. A. Levin 《Chemistry of Heterocyclic Compounds》2003,39(1):96-100
3-Benzoylquinoxalin-2(1H)-one is cyclized with acetic anhydride in the presence of pyridine into 2-oxo-4-phenylpyrano[2,3-b]quinoxaline. 相似文献
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IntroductionInpreviouspaper[1—3],wedescribedthatarenealdoximedehydrodimerandstyreneinre-fluxingchloroformgavelinearadductsand... 相似文献
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O—芳基苯基硫代膦酰肼与异(硫)氰酸酯的加成反应 总被引:2,自引:0,他引:2
合成了一些新的硫代膦酰基-及N,N′-双(硫代膦酰基)氨基硫脲。分离并采用IR、~1H NMR、MS及X衍射确证了N,N′-双[硫代膦酰基]氨基硫脲中是由2个手性磷原子而形成的非对映异构体。讨论了单取代和双取代氨基硫脲的质谱。 相似文献
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The hitherto unreported title compounds were obtained in good yields by the application of [3,3]sigmatropic rearrangement on 4-]2′-propynyloxy] [1]benzothiapyran-2-one and 4-[2′-propenyloxy][1]benzothiapyran-2-one or 4-[2′-chloro-2′-propenyloxy][1]benzothiapyran-2-one respectively. 相似文献
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用Heck反应合成1-羟基-4-(3-吡啶基)丁-2-酮 总被引:1,自引:0,他引:1
在Heck反应条件下,以Ph3P为催化剂配体,由3-卤代吡啶和3-丁烯-1,2-二醇进行偶合可以得到1-羟基-4-(3-吡啶基)丁-2-酮,具有原料易得、合成方法简单的优点. 相似文献
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YU Chen-Xia ZHU Xiao-Tong YAO Chang-Sheng TU Shu-Jiang 《结构化学》2007,26(5):533-536
The title compound (C16H14BrNO) has been synthesized by the reaction of p-tolylamine, Meldrum’s acid and 4-bromo-benzaldehyde, and its structure was characterized by IR, 1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P21/n with a = 7.6850(11), b = 8.3004(11), c = 21.301(3) , β = 95.110(2)°, V = 1353.4(3) 3, Mr = 316.19, Z = 4, Dc = 1.552 g/cm3, μ(MoKα) = 3.028 mm-1, F(000) = 640, the final R = 0.0345 and wR = 0.0768. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and N(1) form a six-membered ring of boat conformation. 相似文献