- SINGLE ELECTRON TRANSFER INITIATED PHOTOCYCLIZATION OF SUBSTITUTED CINNAMIC ACIDS TO CORRESPONDING COUMARINS
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Efficient photocyclization of substituted cinnamic acids to corresponding coumarins, initiated by single electron transfer processes, have been reported.A probabale mechanism has been discussed.
- Pandey, G.,Krishna, A.,Rao, Jampani Madhusudana
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- Syntheses and evaluation of daphnetin derivatives as novel G protein-coupled receptor inhibitors and activators
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A series of daphnetin (7,8-dihydroxycoumarin) derivatives 1–22 were synthesized including sixteen new compounds (1–5, 7–14, 18, 21 and 22) and six known compounds (6, 15–17, 19 and 20). Their pharmacological activities on G protein-coupled receptors (GPCRs) were evaluated by double antibody sandwich ELISA (DAS-ELISA) in vitro. Daphnetin derivatives with various substitution patterns/groups were obtained from inhibitors to activators on GPCRs. Derivatives 2–5, 8, 15, 16 and 18–20 possessed moderate activation potency on GPCRs. Among them, derivatives 3–5, 16 and 19 presented significant activation potency on GPCRs with EC50 values in the range of 1.18–1.91 nM. Derivatives 6, 11, 14 and 18 showed significant inhibitory potency on GPCRs with IC50 values in the range of 1.26–1.38 nM. Moreover, the structure-activity relationships (SARs) of daphnetin derivatives were discussed in detail. The new daphnetic-based GPCRs activators and inhibitors have potentials as future drug candidates for the treatment of metabolic diseases.
- Wang, Yinan,Wang, Jiangming,Fu, Zhe,Sheng, Ruilong,Wu, Wenhui,Fan, Junting,Guo, Ruihua
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- Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran-2-one Aromaticity-Mediated Regioselective Control and Biogenetic Implications
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The synthetic feasibility of the oxidative cleavage: epoxidation of 7-O-geranylscopoletin followed by electrocyclic ring-opening, proposed in the biogenesis of transtaganolides/basiliolides is studied. Unlike the proposed pericyclic reactions, this pathway has not yet been addressed. Three synthetic strategies have been tested consisting of: i) Baeyer–Villiger oxidation of p-quinoids, ii) hydrolysis of quinone monoketals, or iii) direct fragmentation by using oxygen donors. Oxidation of the benzene ring of hydroxylated coumarins has been achieved using peroxyacids, but cleavage took place between undesired positions. The aromaticity conservation of the pyran-2-one cycle during oxidation is the controlling factor of these observed regioselectivities. The use of a 4,5-dihydroxy-2-methoxycinnamate model, in which the pyran-2-one ring does not exert influence on oxidation, has allowed the design of a synthetic sequence toward an analogue of the natural pyran-2-one isolated from Thapsia transtagana, key in the biogenesis. Mechanistic proposals for the obtained results as well as their biogenetic implications are raised.
- álvarez, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
(2020/03/05)
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- Inhibitor daphnetin derivative and application and pharmaceutical composition thereof
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The invention provides an inhibitor daphnetin derivative and application and a pharmaceutical composition thereof. The daphnetin derivative (1-13) or the pharmaceutically acceptable salt or solvent compound thereof is shown as the following formula. The p
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Paragraph 0057-0065
(2020/11/25)
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- Monoalkylation of dihydroxycoumarins via Mitsunobu dehydroalkylation under high intensity ultrasound. The synthesis of ferujol
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Monoalkylation of natural dihydroxycoumarins was carried out by Mitsunobu dehydroalkylation under sonochemical conditions. Aesculetin (6,7-dihydroxycoumarin) was selectively alkylated in good yield with prenyl alcohols at position 7, as clearly shown by N
- Cravotto, Giancarlo,Chimichi, Stefano,Robaldo, Bruna,Boccalini, Marco
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p. 8383 - 8386
(2007/10/03)
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- An efficient preparation of coumarins
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o-Methoxyaryl-aldehydes (or -ketones) react in solid-phase with Meldrum's acid under mild conditions, to give benzylidene derivatives which are cyclized in high yield, with cold sulfuric acid to substituted 3-carboxycoumarins. Thermal decarboxylation, spe
- Rouessac,Leclerc
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p. 2709 - 2715
(2007/10/02)
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- Synthetic studies on naturally occurring coumarins. I. A convenient synthesis of 5,8-dimethoxy- and 7,8-dimethoxycoumarins
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The coumarin isolated from Artemisia carvifolia Wall was proved synthetically to be 7,8-dimethoxycoumarin and not 5,8-dimethoxycoumarin as previously proposed. 3,4-Dimethoxy- and 3,6-dimethoxysalicylaldehydes gave the corresponding coumarins in good yield by the method using phosphorane reagent in N,N-diethylaniline under reflux.
- Ishii,Kenmotsu,Dopke,Harayama
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p. 1770 - 1772
(2007/10/02)
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- COUMARINS IN ARTEMISIA CARUIFOLIA
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Isolation of daphnetin 7-methyl ether, daphnetin dimethyl ether, daphnetin methylene ether, daphnetin 7-methyl-8(3,3-dimethylallyl) ether and 3,4-dimethoxy-2-hydroxycinnamic acid from Artemisia caruifolia is reperted. - Key Word Index: Artemisia caruifolia; Compositae; coumarins; daphnetin derivatives; 3,4-dimethoxy-2-hydroxycinnamic acid.
- Barua, Nabin C.,Sharma, Ram P.,Madhusudanan, K. P.,Thyagarajan, Gopalakrishna,Herz, Werner
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p. 2217 - 2218
(2007/10/02)
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