- A Fourfold Benzodehydroannuleno-Fused Porphyrazine
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Four benzodehydroannulene subunits were implemented on a dibenzoquinoxalinopoprhyrazine core using efficient palladium-mediated alkyne coupling and oxidative acetylene coupling on phenanthrene dione precursors. Despite the significant amount of strain in system, as evidenced by X-ray analysis of an immediate precursor, porphyrazine assembly leads to an extended model for N-doped graphyne with photosensitizing properties.
- K?rte, Fabian,Bruhn, Clemens,Faust, Rüdigger
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p. 1620 - 1624
(2015/06/30)
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- Total syntheses of the tylophora alkaloids cryptopleurine, (-)-antofine, (-)-tylophorine, and (-)-ficuseptine C
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A concise, efficient and modular approach to the tylophora alkaloids is described, a family of potent cytotoxic agents that are equally effective against drug sensitive and multidrug resistant cancer cell lines. The advantages of the chosen route are illustrated by the total syntheses of the phenanthroquinolizidine cryptopleurine (1) and the phenanthroindolizidines (-)-antofine (2), (-)-tylophorine (3), and their only recently isolated congener (-)-ficuseptine C (4). The key steps consist in a Suzuki cross-coupling between a (commercial) boronic acid and a simple aryl-l,2-dihalide followed by elaboration of the resulting products into the corresponding 2-alkynyl-biphenyl derivatives 27, 33, 41 and 46. The latter undergo PtCl2-catalyzed cycloisomerizations with formation of the functionalized phenanthrenes 28, 34, 42 and 47, which were transformed into the targeted alkaloids by a deprotection/Pictet-Spengler annulation tandem. Due to the flexibility and robust character of this approach, it might enable a systematic exploration of the pharmacological profile of this promising class of bioactive natural products.
- Fuerstner, Alois,Kennedy, Jason W.J.
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p. 7398 - 7410
(2007/10/03)
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- Efficient halogenation of aromatic systems using N-halosuccinimides in ionic liquids
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A simple, rapid and highly regioselective green protocol has been developed for the halogenation of aromatic systems with N-halosuccinimides using room temperature ionic liquids (ILs) as novel and recyclable reaction media to produce the corresponding halogenated aromatic compounds in high to quantitative yields. N-Halosuccinimides show enhanced reactivity in ionic liquids thereby reducing the reaction times dramatically and improving the yields substantially.
- Yadav,Reddy,Reddy,Basak,Narsaiah
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- 1,5-EPOXY-2,3,4,5-TETRAHYDRO-1H-3-BENZAZEPINS AND USE IN TREATMENT OF ULCERS
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The synthesis of epoxybenzazepin compounds is described. The novel compounds have anti-ulcer activity.
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