3895-92-9Relevant articles and documents
Structure and NMR properties of 6-substituted-5,6-dihydrobenzo[c] phenanthridine alkaloids
Kadam, Shivaji S.,Maier, Lukas,Solomek, Tomas,Necas, Marek,Smejkal, Karel,Dostal, Jiri,Sklenar, Vladimir,Marek, Radek
, p. 814 - 821 (2013)
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
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
Ishihara, Yuhsuke,Azuma, Shuhei,Choshi, Tominari,Kohno, Kakujirou,Ono, Kanako,Tsutsumi, Hiroyuki,Ishizu, Takashi,Hibino, Satoshi
, p. 1320 - 1333 (2011/04/16)
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).
Total synthesis of chelerythrine, a benzo[c]phenanthridine alkaloid
Ishii,Ishikawa,Takeda,Suzuki,Harayaya
, p. 2002 - 2006 (2007/10/02)
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.
