New alkaloids from THW.

Battersby, A.B.; Kapil, B.S.; Bhakuni, D. S.; Popli, S. P.; Merchant, J. R.; Salgar, S. S.

doi:10.1016/s0040-4039(00)90310-1

Cited by 41 publications

(13 citation statements)

References 7 publications

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“…Herein, we report metal-free reactions of 1,4-diynes and 1-en-4-yn-3-ones with isoquinoline or quinoline N -oxide, affording 3,4-dihydro- 2H -pyrido[2,1- a ]isoquinolines or 2,3-dihydro- 1H -pyrido[1,2- a ]quinolines by cascade CO/CC/C–N bond formation (Scheme e). These products represent interesting targets; pyrido[2,1- a ]isoquinoline and pyrido[1,2- a ]quinoline skeletons are widely found in biologically active alkaloids such as protoemetinol, psychotrine, emetine, and tubulosine . Furthermore, the distinct fluorescence properties of the products are also disclosed.…”

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confidence: 72%

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

et al. 2017

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The metal-free reactions of 1,4-diynes and 1-en-4-yn-3-ones with isoquinoline and quinoline N-oxides are developed, resulting in the formation of 3,4-dihydro-2H-pyrido[2,1-a]isoquinolines and 2,3-dihydro-1H-pyrido[1,2-a]quinolines via cascade C═O/C═C/C-N bond formation. It is the first report in which in the alkyne oxidation by N-oxides both the oxygen atom of N-oxides and the nitrogen atom are involved in a second C-heteroatom bond formation. The reactions showed a broad substrate scope and functional group tolerance. Furthermore, the products were found to display green-blue fluorescence in DMSO with fluorescence quantum yields up to 0.59.

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confidence: 72%

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

et al. 2017

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“…Hz, H-7b), 3.75 (1H, dd, Jϭ12, 6 Hz, H-6Јa), 3.85 (1H, dd, Jϭ11, 5 Hz, H-5Љb), 3 Enzymatic Hydrolysis of 5 to 5a Compound 5 (20.0 mg) was hydrolyzed with crude hesperidinase (16.0 mg) at 37°C for 18 h in 2 ml of H 2 O. The reaction mixture was evaporated to dryness, and then a methanolic solution of the residue was absorbed on silica gel and subjected to silica gel (20 g, Fϭ15 mm, Lϭ20 cm) column chromatography with CHCl 3 (100 ml), and CHCl 3 -MeOH (19 : 1, 100 ml, 9 : 1, 100 ml, 17 : 3, 100 ml and 7 : 3, 300 ml), 20 g fractions being collected.…”

Section: Jϭ6mentioning

confidence: 99%

Platanionosides D—J: Megastigmane Glycosides from the Leaves of Alangium platanifolium (SIEB. et ZUCC.) HARMS var. platanifolium SIEB. et ZUCC.

Otsuka

Tamaki

2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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There are three Alangiaceous plants in Japan. 1) Alangium premnifolium grows in the southernmost part and A. platanifolium var. trilobum in wide areas of the northern to southern parts of Japan, and the title plant is restricted to the areas of western Yamaguchi and Fukuoka Prefectures. In a previous work, considerable numbers of megastigmane glycosides were isolated from the leaves of A. premnifolium. 2) At first, investigation of Alangiaceae plants was performed in order to isolate ipecac alkaloids. 3) However, this has not been successful so far, except for the isolation of alangiside. 4) Phytochemical isolation work on the title plant has afforded three megastigmane glycosides 5) and several phenolic glycosides. 6) Further investigation yielded seven new megastigmane glycosides ( Fig. 1) along with five known compounds (Fig. 2). This paper deals with the structural elucidation of these new megastigmane glycosides. Results and DiscussionAir-dried leaves of A. platanifolium var. platanifolium were extracted with MeOH, followed by partitioning between solvents of increasing polarity, namely, n-hexane, EtOAc and n-BuOH. The n-BuOH-soluble fraction was purified using a highly porous synthetic resin, octadecyl silica (ODS), and silica gel column chromatographies, and then subjected to droplet counter-current chromatography (DCCC) to give 12 pure megastigmane glycosides. Five of them were known glycosides, being identified as (6S,9R)-roseoside, 7) alangionosides A, 8) H 7) and K, 7) and linarionoside C. 9) Platanionoside D (1), [a] D Ϫ25°, was isolated as an amorphous powder and its elemental composition, C 25 H 44 O 12 , was deduced from the observation of a quasi-molecular ion peak in negative-ion high-resolution (HR) FAB-mass spectrometry. The IR spectrum indicated that 1 was a glycosidic compound. The 1 H-NMR spectrum showed the presence of two singlet and two doublet methyls, and two doublet signals (d H 4.335, d, Jϭ8 Hz and 4.338, d, Jϭ8 Hz), which were assigned as two anomeric protons of sugar moieties. The 13 C-NMR spectrum of 1 indicated the presence of two terminal b-glucopyranose units, and the remaining 13 signals were expected to present a megastigmane skeleton. These signals were assigned to four methyls, four methylenes, four methines, two of which were substituted by oxygen atoms (d C 75.8, 76.2), and one quaternary carbon. These functionalities and the relative arrangement of the ring protons, deduced * To whom correspondence should be addressed. e-mail: hotsuka@hiroshima-u.ac. From the leaves of Alangium paltanifolium var. platanifolium, collected in Fukuoka Prefecture, twelve further megastigmane glycosides were isolated. Seven of them, named platanionosides D-J (1-7), were found to be new compounds. Their structures were elucidated from spectroscopic evidence and their absolute structures were determined from b b-D-glucosylation-induced shift trends of 13 C-NMR and by application of a modified Mosher's method.

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“…Emetine 1 and protoemetinol 2 (Scheme ) are two examples of secologanine dopamine alkaloids, a family of compounds that occur in plants and display, among the others, emetic, antiparasitic, antiviral and anticancer properties…”

Section: Introductionmentioning

confidence: 99%

Access to Polycyclic Alkaloid‐Like Structures by Coupling the Passerini and Ugi Reactions with Two Sequential Metal‐Catalyzed Cyclizations

et al. 2016

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Complex polycyclic compoundsr esembling some natural alkaloids have been preparedi no nly three high yieldings teps by combining the Ugi or Passerinim ulticomponent reactions with two metalcatalyzed cyclizations:a ni ntramolecular Tsuji-Trost reactiono ft he isocyanide-derived amide followed by ar ing-closing metathesis. Scaffold diversity mayb e explored by the appropriate choice of starting unsa-turated isocyanides.T he Tsuji-Trost cyclization proceeds with moderate to good diastereoselectivity, and the major diastereomer was in most cases isolated in the pure form.Scheme 3. Assessment of the methodology on model compounds.

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New alkaloids from THW.

Cited by 41 publications

References 7 publications

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

Platanionosides D—J: Megastigmane Glycosides from the Leaves of <i>Alangium platanifolium</i> (S<small>IEB</small>. et Z<small>UCC</small>.) H<small>ARMS</small> var. <i>platanifolium</i> S<small>IEB</small>. et Z<small>UCC</small>.

Access to Polycyclic Alkaloid‐Like Structures by Coupling the Passerini and Ugi Reactions with Two Sequential Metal‐Catalyzed Cyclizations

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New alkaloids from THW.

Cited by 41 publications

References 7 publications

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

Cascade C═O/C═C/C–N Bond Formation: Metal-Free Reactions of 1,4-Diynes and 1-En-4-yn-3-ones with Isoquinoline and Quinoline N-Oxides

Platanionosides D&mdash;J: Megastigmane Glycosides from the Leaves of <i>Alangium platanifolium</i> (S<small>IEB</small>. et Z<small>UCC</small>.) H<small>ARMS</small> var. <i>platanifolium</i> S<small>IEB</small>. et Z<small>UCC</small>.

Access to Polycyclic Alkaloid‐Like Structures by Coupling the Passerini and Ugi Reactions with Two Sequential Metal‐Catalyzed Cyclizations

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Product

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About

Platanionosides D—J: Megastigmane Glycosides from the Leaves of <i>Alangium platanifolium</i> (S<small>IEB</small>. et Z<small>UCC</small>.) H<small>ARMS</small> var. <i>platanifolium</i> S<small>IEB</small>. et Z<small>UCC</small>.