Revision of the structure of fagaridine based on the comparison of UV and NMR data of synthetic compounds.
Fagaridine is a quaternary benzo[c]phenanthridine alkaloid, originally isolated from Fagara xanthoxyloides in 1973. The assigned structure of this alkaloid was 7-hydroxy-8-methoxy-5-methyl-2, 3-(methylenedioxy)benzo[c]phenanthridinium (1). We have synthesized this compound, coded NK109, aiming at a practical antitumor drug, and during synthetic studies we questioned the original assigned structure. Thus, we synthesized 8-hydroxy-7-methoxy-5-methyl-2, 3-(methylenedioxy)benzo[c]phenanthridinium (2), isomer of the assigned structure, and compared the spectroscopic data of both 1 and 2. The NMR data of 1 and 2 were very similar, but the UV spectra were completely different. The UV data for fagaridine agreed with these for 2; consequently, the true structure of fagaridine is 2, not 1.
Pharmaceuticals Group, Nippon Kayaku Company, Ltd., 31-12, Shimo 3-Chome, Kita-ku, Tokyo 115-8588, Japan. kendama@kk.iij4u.or.jp
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Nakanishi
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Suzuki
D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry*; D053119:Benzophenanthridines; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010617:Phenanthridines / Q000737:chemistry*; D019685:Rosales / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D000972:Antineoplastic Agents, Phytogenic; D053119:Benzophenanthridines; C108284:NK 109; D010617:Phenanthridines