Phytochemical investigation of Smith. (Rubiaceae), an African ethnomedicinal plant, yielded a new indolo[2,3-a]quinolizidine alkaloid, nauclealatimide , two previously unknown lignans named nauclealignan A and B , as well rhemaneolignan B and spicatolignan A from the hydromethanolic extract obtained after ultrasonication of the stem bark. Their chemical structures were elucidated using IR, NMR (1D and 2D) and HRESIMS spectral evidence as well as comparisons with existing literature data.
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A new strictosamide-based indolo[2,3-a]quinolizidine alkaloid and two new lignans from the stem bark of Smith.
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State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China.
Phytochemical investigation of Smith. (Rubiaceae), an African ethnomedicinal plant, yielded a new indolo[2,3-a]quinolizidine alkaloid, nauclealatimide , two previously unknown lignans named nauclealignan A and B , as well rhemaneolignan B and spicatolignan A from the hydromethanolic extract obtained after ultrasonication of the stem bark. Their chemical structures were elucidated using IR, NMR (1D and 2D) and HRESIMS spectral evidence as well as comparisons with existing literature data.
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Chemistry
June 2024
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, 260-8675, Chiba, Japan.
There are many indole alkaloids that contain diverse functional groups attached to the benzene ring on the indole core. Promising biological activities of these alkaloids have been reported. Herein, we report the indole C5-selective bromination of indolo[2,3-a]quinolizidine alkaloids by adding nearly equimolar amounts of Br ⋅ PyH and HCl in MeOH.
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Instituto de Investigacao do Medicamento (iMed.ULisboa), Faculdade de Farmacia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
Corynantheine alkaloids with a tetracyclic indole[2,3-a]-quinolizidine motif are an important issue in academia and in the life science industries due to their broad bioactivity profile. In particular, the main biological effects described for indoloquinolizidines include analgesic, anti-inflammatory, antihypertensive, and antiarrhythmic activities, as well as inhibition of multiple ion channels, affinity for opioid receptors, and activity against Leishmania. For that reason, in the last decades, numerous efforts have been invested in the development of novel synthetic strategies to obtain the indole[2,3-a]-quinolizidine system.
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