- CASSIADININE, A CHROMONE ALKALOID AND (+)-6-HYDROXYMELLEIN, A DIHYDROISOCOUMARIN FROM CASSIA SIAMEA
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Cassiadinine, a new chromone alkaloid and (+)-6-hydroxymellein, a new dihydroisocoumarin isomer have been isolated together with three triterpenoids, cycloart-23-en-3β,25-diol, friedelin and betulin, a chromone derivative, 5-acetonyl-7-hydroxy-2-methylchromone and γ-sitosterol from the petrol and chloroform extracts of the flowers of Cassia siamea. Key Word Index - Cassia siamea; Leguminosae; alkaloid; cassiadinine; dihydroisocoumarin; (+)-6-hydroxymellein; 5-acetonyl-7-hydroxy-2-methylchromone; cycloart-23-ene-3β,25-diol; betulin; friedelin; γ-sitosterol.
- Biswas, Kshetra M.,Mallik, Haimanti
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- Transformation of barakol into cassiarins A, B, and their derivatives
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Three semi-syntheses of cassiarins A and B from barakol are described. The route involving use of anhydrobarakol chloride as a key precursor showed most versatility because it does not require an expensive catalyst, protection of functional groups, or chromatographic purification, allowing the facile preparation of eight cassiarin derivatives. The photophysical properties of these compounds were characterized by UV-vis absorption, fluorescence emission, and quantum yield.
- Kanputhorn, Sarawut,Petsom, Amorn,Thamyongkit, Patchanita
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experimental part
p. 7539 - 7543
(2010/12/20)
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- Synthesis and structure-activity relationships of cassiarin A as potential antimalarials with vasorelaxant activity
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Cassiarin A 1, a tricyclic alkaloid, isolated from the leaves of Cassia siamea (Leguminosae), shows powerful antimalarial activity against Plasmodium falciparum in vitro as well as P. berghei in vivo, which may be valuable leads for novel antimalarials. Interactions of parasitized red blood cells (pRBCs) with endothelium in aorta are especially important in the processes contribute to the pathogenesis of severe malaria. Nitric oxide (NO) reduces endothelial expression of receptors/adhesion molecules used by pRBC to adhere to vascular endothelium, and reduces cytoadherence of pRBC to vascular endothelium. Cassiarin A 1 showed vasorelaxation activity against rat aortic ring, which may be related with NO production. A series of a hydroxyl and a nitrogen-substituted derivatives and a dehydroxy derivative of 1 have been synthesized as having potent antimalarials against P. falciparum with vasodilator activity, which may reduce cytoadherence of pRBC to vascular endothelium. Cassiarin A 1 exhibited a potent antimalarial activity and a high selectivity index in vitro, suggesting that the presence of a hydroxyl and a nitrogen atom without any substituents may be important to show antimalarial activity. Relative to cassiarin A, a methoxy derivative showed more potent vasorelaxant activity, although it did not show improvement for inhibition of P. falciparum in vitro. These cassiarin derivatives may be promising candidates as antimalarials with different mode of actions.
- Morita, Hiroshi,Tomizawa, Yuichiro,Deguchi, Jun,Ishikawa, Tokio,Arai, Hiroko,Zaima, Kazumasa,Hosoya, Takahiro,Hirasawa, Yusuke,Matsumoto, Takayuki,Kamata, Katsuo,Ekasari, Wiwied,Widyawaruyanti, Aty,Wahyuni, Tutik Sri,Zaini, Noor Cholies,Honda, Toshio
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experimental part
p. 8234 - 8240
(2010/03/25)
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- Biomimetic total syntheses of cassiarins A and B
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(Chemical Equation Presented) Total syntheses of cassiarins A and B have been efficiently accomplished using a common strategy with biomimetic considerations. Key reactions involved in this synthesis include a Negishi-type coupling, a Ag(I)-promoted formation of the tricyclic 8H-pyrano[2,3,4-de] chromen-8-one core, and a sequential amine-condensation and cyclization. Three new analogues of cassiarin A bearing different substituents at the C-11 position were synthesized in parallel from the same intermediate. In addition, two other transformations to the key tricyclic cores and cassiarins A and B were achieved from corresponding chemically equivalent precursors.
- Yao, Yuan-Shan,Yao, Zhu-Jun
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p. 5221 - 5225
(2008/12/21)
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- Syntheses of Naturally Occuring 5-Carbonylmethyl-7-hydroxy-2-methyl-chromones and -chromanone (Studies on the β-Carbonyl Compounds Connected with the β-Polyketides. X)
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Naturally occuring 5-carbonylmethyl-7-hydroxy-2-methyl-chromones, -chromanone and an analogue 1, 2, 3, and 4 were synthesized by two routes from a self condensation product 6 of dimethyl acetonedicarboxylate, and the pyrone 10.
- Takeuchi, Naoki,Sasaki, Yuki,Kosugi, Yoko,Tobinaga, Seisho
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p. 2012 - 2015
(2007/10/02)
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- TWO CHROMONE GLYCOSIDES FROM CASSIA MULTIJUGA
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Two new 2-methylchromone glycosides have been identified in the leaves of Cassia multijuga.Key Word Index - Cassia multijuga; Leguminosae; leaves; chromone glycosides.
- Singh, J.
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p. 1177 - 1179
(2007/10/02)
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