- Structure and NMR properties of 6-substituted-5,6-dihydrobenzo[c] phenanthridine alkaloids
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We report a preparation of new 6-substituted-5,6-dihydrobenzo[c] phenanthridines by the reaction of azoles with quaternary benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine. The prepared compounds have been characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. Conformational behaviors of carbazole derivatives in solution have been investigated by low-temperature NMR experiments. Barriers to rotation around newly formed C6-N bonds were determined to be 12-13 kcal/mol. Quantum chemical calculations have been used to reproduce the experimental observations. Large structural effects on several 1H NMR resonances were observed experimentally, analyzed by Density Functional Theory (DFT) calculations at B3LYP/6-311+G(d,p)/PCM level, and interpreted by ring-current effects of the benzo[c]phenanthridine and carbazole units. Copyright 2013 John Wiley & Sons, Ltd. Barrier to rotation around C-N bond was determined experimentally by low-temperature 1H NMR spectroscopy and calculated by using density functional theory (B3LYP/6-311+G(d,p)). Structural effects on selected 1H NMR resonances are rationalized by ring currents of benzo[c]phenanthridine and carbazole moieties. Copyright
- Kadam, Shivaji S.,Maier, Lukas,Solomek, Tomas,Necas, Marek,Smejkal, Karel,Dostal, Jiri,Sklenar, Vladimir,Marek, Radek
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- Palladium-catalyzed tandem reaction to construct benzo[c]phenanthridine: Application to the total synthesis of benzo[c]phenanthridine alkaloids
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A concise and efficient synthesis of benzo[c]phenanthridines was accomplished by the palladium-catalyzed ring-opening coupling of azabicyclic alkene with o-iodobenzoates, followed by tandem cyclization. The strategy was successfully applied in the total synthesis of benzo[c]phenanthridine alkaloids such as sanguinarine, chelerythrine, nitidine and avicine.
- Lv, Pei,Huang, Kanglun,Xie, Longguan,Xu, Xiaohua
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p. 3133 - 3135
(2011/05/15)
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- Total synthesis of benzo[c]phenanthridine alkaloids based on a microwave-assisted electrocyclic reaction of the aza 6π-electron system and structural revision of broussonpapyrine
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Total syntheses of the des-N-methyl (nor) type of benzo[c]phenanthridine alkaloids 1a-f and 19 and benzo[c]phenanthridine alkaloids, chelerythrine (2d), and broussonpapyrine (2f) were achieved. The key step was the construction of tetracyclic 10,11-dihydrobenzo[c]phenanthridines using a microwave-assisted electrocyclic reaction of the 2-cycloalkenylbenzaldoxime methyl ether 4 as an aza 6π-electron system, which was derived in two steps from a Suzuki-Miyaura cross-coupling reaction of 2-bromobenzaldehyde 6 with 2-(3,4-dihydro-6,7- methylenedioxynaphthyl)boronic acid pinacol ester 7. In addition, the exact structure of broussonpapyrine (2f) (2,3,9,10-tetraoxygenated type) was determined to be chelerythrine (2d).
- Ishihara, Yuhsuke,Azuma, Shuhei,Choshi, Tominari,Kohno, Kakujirou,Ono, Kanako,Tsutsumi, Hiroyuki,Ishizu, Takashi,Hibino, Satoshi
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p. 1320 - 1333
(2011/04/16)
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- PSEUDOBASE BENZO [C] PHENANTHRIDINES WITH IMPROVED EFFICACY, STABILITY, AND SAFETY
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Pseudobase benzo[c]ρhenanthridines and the pharmaceutically acceptable salts thereof of Formula I (i) are provided herein. The variables R, Rj, R2, R3, and R4 are defined herein. Certain pseudobase benzo[c]phenanthridines provided herein act as prodrugs, targeting the parent benzo[c]phenanthridinium alkaloid to hydrophilic or hydrophobic regions in the body. Pharmaceutical compositions comprising a pseudobase benzo[c]phenanthridine and a carrier, excipient, or diluent are provided herein. Methods of treating or preventing microbial, fungal and or viral infections and methods of treating diseases and disorders responsive to protein kinase C modulation, topoisomerase I, and/or topoisomerase II modulation are also provided.
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Page/Page column 48-49
(2008/06/13)
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- Total synthesis of chelerythrine, a benzo[c]phenanthridine alkaloid
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By taking advantage of our novel synthetic methods involving CsF-mediated Claisen rearrangement of an aryl propargyl ether to a 2-methylbenzolfuran and oxidative cleavage of the furan ring to a salicylaldehyde, total synthesis of chelerythrine, a benzo[c]phenanthridine alkaloid, was accomplished via the common intermediate (5) prepared through the two routes shown in Chart 3.
- Ishii,Ishikawa,Takeda,Suzuki,Harayaya
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p. 2002 - 2006
(2007/10/02)
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- Chemical Transformation of Protoberberines. Part 9. A Biomimetic Synthesis of Oxychelerythrine, Dihydrochelerythrine, and Chelerythrine from Berberine
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Fully aromatised benzophenanthridine alkaloids, oxychelerythrine (4), dihydrochelerythrine (9), and chelerythrine (10) have been efficiently synthesized from berberine (1), a protoberberine alkaloid, via oxidative C(6)-N bond cleavage, followed by recyclisation betwen the C-6 and C-13 positions of (1) by a biogenetic process.
- Hanaoka, Miyoji,Motonishi, Toshio,Mukai, Chisato
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p. 2253 - 2256
(2007/10/02)
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- A Biomimetic Conversion of Berberine into Chelerythrine and Dihydrochelerythrine
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A novel and efficient synthesis of the benzophenanthridine alkaloids, chelerythrine and dihydrochelerythrine, from berberine was developed via a biogenetic route.
- Hanaoka, Miyoji,Motonishi, Toshio,Mukai, Chisato
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p. 718 - 719
(2007/10/02)
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