- Lamellarins as inhibitors of P-glycoprotein-mediated multidrug resistance in a human colon cancer cell line
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Chemical analysis of a Didemnum sp. (CMB-01656) collected during scientific Scuba operations off Wasp Island, New South Wales, yielded five new lamellarins A1 (1), A2 (2), A3 (3), A4 (4) and A5 (5) and eight known lamellarins C (6), E (7), K (8), M (9), S (10), T (11), X (12) and χ (13). Analysis of a second Didemnum sp. (CMB-02127) collected during scientific trawling operations along the Northern Rottnest Shelf, Western Australia, yielded the new lamellarin A6 (14) and two known lamellarins G (15) and Z (16). Structures were assigned to 1-16 on the basis of detailed spectroscopic analysis with comparison to literature data and authentic samples. Access to this unique library of natural lamellarins (1-16) provided a rare opportunity for structure-activity relationship (SAR) investigations, probing interactions between lamellarins and the ABC transporter efflux pump P-glycoprotein (P-gp) with a view to reversing multidrug resistance in a human colon cancer cell line (SW620 Ad300). These SAR studies, which were expanded to include the permethylated lamellarin derivative (17) and a series of lamellarin-inspired synthetic coumarins (19-24) and isoquinolines (25-26), successfully revealed 17 as a promising new non-cytotoxic P-gp inhibitor pharmacophore. Copyright
- Plisson, Fabien,Huang, Xiao-Cong,Zhang, Hua,Khalil, Zeinab,Capon, Robert J.
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- Synthesis and structure-activity relationship of coumarins as potent Mcl-1 inhibitors for cancer treatment
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Myeloid cell leukemia-1 (Mcl-1) is a validated and attractive target for cancer therapy. Over-expression of Mcl-1 in many cancers allows cancer cells to evade apoptosis and contributes to their resistance to current chemotherapeutics. In this study, more than thirty coumarin derivatives with different substituents were designed and synthesized, and their Mcl-1 inhibitory activities evaluated using a fluorescence polarization-based binding assay. The results showed that the catechol group was a key constituent for Mcl-1 inhibitory activity of the coumarins, and methylation of the catechol group led to decreased inhibitory activity. The introduction of a hydrophobic electron-withdrawing group at the C-4 position of 6,7-dihydroxycoumarin, enhanced Mcl-1 inhibitory capacity, and a hydrophilic group in this position was unbeneficial to the inhibitory potency. In addition, the introduction of a nitrogen-containing group to the C-5 or C-8 position, which allowed an intramolecular hydrogen bond, was also unfavorable for Mcl-1 inhibition. Among all coumarins tested, 4-trifluoromethyl-6,7-dihydroxycoumarin (Cpd 4) displayed the most potent inhibitory activity towards Mcl-1 (Ki = 0.21 ± 0.02 μM, IC50 = 1.21 ± 0.56 μM, respectively), for which the beneficial effect on taxol resistance was also validated in A549 cells. A strong interaction between Cpd 4 and Mcl-1 in docking simulations further supported the observed potent Mcl-1 inhibition ability of Cpd 4. 3D-QSAR analysis of all tested coumarin derivatives further provides new insights into the relationships linking the inhibitory effects on Mcl-1 and the steric-electrostatic properties of coumarins. These findings could be of great value for medicinal chemists for the design and development of more potent Mcl-1 inhibitors for biomedical applications.
- Xia, Yang-Liu,Wang, Jing-Jing,Li, Shi-Yang,Liu, Yong,Gonzalez, Frank J.,Wang, Ping,Ge, Guang-Bo
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- Psoralen and coumarin photochemistry in HSA complexes and DMPC vesicles
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The photochemistry and photophysics of several psoralens and coumarins have been examined in human serum albumin (HSA) complexes and dimyristoylphosphatidylcholine (DMPC) vesicles. Fluorescence spectroscopy indicates that there are multiple binding sites with polarities that are intermediate between those of acetonitrile and water for the substrates complexed to HSA. In the case of the 6,7-dimethoxycoumarin-HSA complex, laser flash photolysis experiments provide evidence for the formation of radical cation in addition to triplet. Radical cations are not detected for other coumarin-HSA complexes, either due to a lower yield of formation or to rapid reaction of an initial radical cation with adjacent amino acids. Fluorescence spectra for coumarins indicate that they are primarily solubilized in the polar headgroup region in DMPC vesicles. Consistent with this, radical cations generated by photoionization are detected in transient experiments. For dimethoxycoumarins the radical cation is long-lived, indicating rapid exit from the vesicle and decay in the aqueous phase. However, 4,5′,8- trimethylpsoralen and 7-ethoxy-4-hexadecylcoumarin radical cations are much shorter-lived, presumably due to rapid decay by electron recombination in the vesicle. The results for both HSA complexes and vesicles indicate that radical ions may play a role in psoralen and coumarin photochemistry in a cellular environment.
- Chen,Rinco,Popov,Vuong,Johnston, Linda J.
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- Design, Synthesis, and Characterization of Small-Molecule Reagents That Cooperatively Provide Dual Readouts for Triaging and, When Necessary, Quantifying Point-of-Need Enzyme Assays
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A newly designed small molecule reagent provides both qualitative and quantitative readouts in assays that detect enzyme biomarkers. The qualitative readout enables rapid triaging of samples so that only samples that contain relevant concentrations of the target analyte must be quantified. The reagent is accessible in essentially three steps and 34% overall yield, is stable as a solid when heated to 44 °C for >1 month, and does not produce background signal when used in an assay. This paper describes the design and synthesis of the reagent, characterizes its response properties, and establishes the scope of its reactivity.
- Brooks, Adam D.,Mohapatra, Hemakesh,Phillips, Scott T.
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- Cascade synthesis of 3-alkenylcoumarins by palladium-catalyzed reaction of phenols and ethyl propiolate
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A highly effective cascade process giving 3-alkenylcoumarins is furnished by a series of reactions involving palladaarylation of ethyl propiolate with phenols, intramolecular transesterification to 3-coumarylpalladium species, its alkyne insertion, and protonation. [Pd(OAc)2(dppe)] is an effective catalyst for the synthesis of 3-alkenylcoumarins from phenols and ethyl propiolate.
- Kitamura, Tsugio,Tatemoto, Kotaro,Sakai, Mariko,Oyamada, Juzo
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- A Convenient Synthesis of a Simple Coumarin from Salicylaldehyde and Wittig Reagent (I): A Synthesis of Methoxy- and Hydroxycoumarins
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Reaction of methoxy- and hydroxysalicylaldehydes (1) with phosphorane in diethylaniline under reflux gave only coumarins (3) in high yields except for 3-methoxysalicylaldehyde (1b).It was clarified that methoxy group(s) at C4 and C6 on 1 facilitated the formation of 3.
- Harayama, Takashi,Katsuno, Keiko,Nishioka, Hiromi,Fujii, Masako,Nishita, Yoshitaka,et al.
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- 13C NMR SPECTRA AND STRUCTURE OF BUNGEIDIOL AND ITS TRASFORMATION PRODUCTS
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The results are given of a study of the 13C NMR spectra of the new terpenoid coumarin bungeidiol (I) and of the products of its transformation (II) and (III) and some model compounds (IV-VII).On the basis of the results obtained from these 13C NMR spectra and with the use of additive contributions depending on the nature and positions of various substituents (hydroxy and methoxy groups) in the aromatic ring, the structure (I) has been confirmed and a complete assignmant of the signals of all the carbon atoms both in the coumarin ring and in the aliphatic part of the molecule of (I) has been made.
- Abyshev, A. Z.,Zmeikov, V. P.
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- Gold(I)-Catalyzed Intramolecular Hydroarylation of Phenol-Derived Propiolates and Certain Related Ethers as a Route to Selectively Functionalized Coumarins and 2 H-Chromenes
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Methods are reported for the efficient assembly of a series of phenol-derived propiolates, including the parent system 56, and their Au(I)-catalyzed cyclization (intramolecular hydroarylation) to give the corresponding coumarins (e.g., 1). Simple syntheses of natural products such as ayapin (144) and scoparone (145) have been realized by such means, and the first of these subject to single-crystal X-ray analysis. A related process is described for the conversion of propargyl ethers such as 156 into the isomeric 2H-chromene precocene I (159), a naturally occurring inhibitor of juvenile hormone biosynthesis.
- Cervi, Aymeric,Vo, Yen,Chai, Christina L. L.,Banwell, Martin G.,Lan, Ping,Willis, Anthony C.
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p. 178 - 198
(2020/12/22)
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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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- Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and N, N-Dimethylformamide Dimethyl Acetal
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Aluminum triiodide is harnessed by N,N-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers via neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, tert-butyldimethylsilyl (TBS), and tert-butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.
- Sang, Dayong,Yue, Huaxin,Zhao, Zhengdong,Yang, Pengtao,Tian, Juan
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p. 6429 - 6440
(2020/07/14)
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- Escoparone chemical whole synthetic method
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The invention discloses escoparone chemical whole synthetic method, which belongs to the technical field of chemical synthesis, escoparone chemical full-synthetic method is 2, 4, 5 - trimethoxybenzaldehyde de-methyl generating 4 - dihydroxy - 5 - methoxybenzaldehyde; 4 - dihydroxy - 5 - methoxy benzaldehyde with malonic acid to generate the cyclization reaction to produce the 3 - carboxyl scopolamine lactone; 3 - carboxyl scopolamine lactone by microwave auxiliary decarboxylative generating scopolamine lactone; scopolamine lactone by methylation get escoparone, aims to solve the low efficiency of the plant extract, the disadvantage of low yield and the synthetic yield is low, high cost, is not suitable for the industrial application of the shortcomings.
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- Synthesis of 7-Azido-3-Formylcoumarin – A Key Precursor in Bioorthogonally Applicable Fluorogenic Dye Synthesis
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Coumarins represent an important group of natural products and a common part of various drugs and fluorescent dyestuffs. Herein, we present the synthesis of a coumarin that can serve as a key starting material in the design and synthesis of bioorthogonally applicable fluorogenic dyes. The synthesis of 7-azido-3-formylcoumarin started from 7-diallylaminocoumarin. This allyl protected aminocoumarin is otherwise hard to obtain by conventional methods but was conveniently accessed in good yields by a sequential, Wittig-reaction–UV isomerization process. This sequential approach was studied in more details and applied for the synthesis of a series of substituted coumarins even in one-pot.
- Pünk?sti, Zoltán,Kele, Péter,Herner, András
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supporting information
p. 1183 - 1188
(2018/03/21)
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- Synthesis and acaricidal activities of scopoletin phenolic ether derivatives: Qsar, molecular docking study and in silico Adme predictions
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Thirty phenolic ether derivatives of scopoletin modified at the 7-hydroxy position were synthesized, and their structures were confirmed by IR,1H-NMR,13C-NMR, MS and elemental analysis. Preliminary acaricidal activities of these compounds against female adults of Tetranychus cinnabarinus (Boisduval) were evaluated using the slide-dip method. The results indicated that some of these compounds exhibit more pronounced acaricidal activity than scopoletin, especially compounds 32, 20, 28, 27 and 8 which exhibited about 8.41-, 7.32-, 7.23-, 6.76-, and 6.65-fold higher acaricidal potency. Compound 32 possessed the the most promising acaricidal activity and exhibited about 1.45-fold higher acaricidal potency against T. cinnabarinus than propargite. Statistically significant 2D-QSAR model supports the observed acaricidal activities and reveals that polarizability (HATS5p) was the most important parameter controlling bioactivity. 3D-QSAR (CoMFA: q2 = 0.802, r2 = 0.993; CoMSIA: q2 = 0.735, r2 = 0.965) results show that bulky substituents at R4, R1, R2 and R5 (C6, C3, C4, and C7) positions, electron positive groups at R5 (C7) position, hydrophobic groups at R1 (C3) and R2 (C4), H-bond donors groups at R1 (C3) and R4 (C6) will increase their acaricidal activity, which provide a good insight into the molecular features relevant to the acaricidal activity for further designing novel acaricidal agents. Molecular docking demonstrates that these selected derivatives display different bide modes with TcPMCA1 from lead compound and they interact with more key amino acid residues than scopoletin. In silico ADME properties of scopoletin and its phenolic ether derivatives were also analyzed and showed potential to develop as good acaricidal candidates.
- Luo, Jinxiang,Lai, Ting,Guo, Tao,Chen, Fei,Zhang, Linli,Ding, Wei,Zhang, Yongqiang
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- Prenylcoumarins in One or Two Steps by a Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination/Cyclization Sequence
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The one-pot synthesis of 8-prenylcoumarins from 1,1-dimethylallylated salicylaldehydes and the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane under microwave conditions was found to have a limited scope. The sequence suffers from a difficult and sometimes low-yielding synthesis of the precursors and from a competing deprenylation upon microwave irradiation. This side reaction occurs in particular with electron rich arenes with two or more alkoxy groups at adjacent positions, a prominent substitution pattern in naturally occurring 8-prenylcoumarins. Both limitations of this one-step sequence were overcome by a two-step synthesis consisting of a microwave-promoted tandem allyl ether Claisen rearrangement/Wittig olefination and a subsequent olefin cross metathesis with 2-methyl-2-butene. The cross metathesis step proceeds with a high selectivity and yields exclusively the desired prenyl, rather than the alternative crotyl substituent. Several naturally occurring 8-prenylcoumarins that were previously inaccessible have been synthesized in good overall yields along this route.
- Schultze, Christiane,Schmidt, Bernd
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p. 5210 - 5224
(2018/05/17)
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- Scopolamine phenolic ether derivative, and preparation methods and application thereof
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The invention relates to a scopolamine phenolic ether derivative, and preparation methods and an applicationm thereof. The scopolamine phenolic ether derivative is represented by the general formula I and II. The compound of the general formula I prepared through reacting substituted halohydrocarbon with 7-hydroxy-6-methoxycoumarin; and the compound of the formula II is prepared through a substituting reaction of a substituted iodoacetamide compound and scopolamine. The preparation methods are simple, and the scopolamine phenolic ether derivative prepared in the invention has a very good acaricidal effect, can be applied to bio-agriculture, and has a very good application prospect.
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Paragraph 0021-0023; 0027
(2017/08/31)
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- Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
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An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity, and proceeds via C-H bond activation proven by deuterium incorporation studies.
- Gadakh, Sunita K.,Dey, Soumen,Sudalai, Arumugam
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p. 11544 - 11550
(2015/12/04)
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- Semisynthesis, ex vivo evaluation, and SAR studies of coumarin derivatives as potential antiasthmatic drugs
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Asthma is a chronic inflammatory disorder that causes contraction in the smooth muscle of the airway and blocking of airflow. Reversal the contractile process is a strategy for the search of new drugs that could be used for the treatment of asthma. This work reports the semisynthesis, ex vivo relaxing evaluation and SAR studies of a series of 18 coumarins. The results pointed that the ether derivatives 1-3, 7-9 and 13-15 showed the best activity (E max = 100%), where compound 2 (42 μM) was the most potent, being 4-times more active than theophylline (positive control). The ether homologation (methyl, ethyl and propyl) in position 7 or positions 6 and 7 of coumarins lead to relaxing effect, meanwhile formation of esters generated less active compounds than ethers. The SAR analysis showed that it is necessary the presence of two small ether groups and the methyl group at position 4 (site 3) encourage biological activity through soft hydrophobic changes in the molecule, without drastically affecting the cLogP.
- Sánchez-Recillas, Amanda,Navarrete-Vázquez, Gabriel,Hidalgo-Figueroa, Sergio,Rios, María Yolanda,Ibarra-Barajas, Maximiliano,Estrada-Soto, Samuel
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p. 400 - 408
(2014/04/17)
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- Total synthesis of six 3,4-unsubstituted coumarins
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In this article we describe a new methodology for the total synthesis of 3,4-unsubstituted coumarins from commercially available starting materials. Six examples were prepared, including five naturally occurring coumarins-7-hydroxy- 6,8-dimethoxycoumarin (isofraxidin), 7-hydroxy-6-methoxycoumarin (scopoletin), 6,7,8-trimethoxycoumarin, 6,7-dimethoxycoumarin (scoparone), and 7,8-dihydroxycoumarin (daphnetin) and one synthetic coumarin, 7-hydroxy-6-ethoxycoumarin. Moreover, five important o-hydroxybenzaldehyde intermediates were also obtained, namely 2,4-dihydroxy-3,5- dimethoxybenzaldehyde, 2,4-dihydroxy-5-methoxybenzaldehyde, 5-ethoxy-2,4- dihydroxybenzaldehyde, 2-hydroxy-3,4,5-trimethoxybenzaldehyde, and 2-hydroxy-4,5-dimethoxybenzaldehyde. The method developed herein involves just three or four steps and allows for the rapid synthesis of these important molecules in excellent yields. This is the first synthesis of 6,7,8-trimethoxycoumarin and 7-hydroxy-6-ethoxycoumarin.
- Gao, Wenqing,Li, Qingyong,Chen, Jian,Wang, Zhichao,Hua, Changlong
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p. 15613 - 15623
(2014/01/17)
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- New approach for the construction of the coumarin frame and application in the total synthesis of natural products
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A new synthetic approach is described for building the coumarin scaffold through the Lewis acid-promoted cyclization of novel aryl 3-(dimethylamino)prop- 2-enoates 2a - 2f. The latter precursors were prepared via aminomethylenation of the corresponding aryl acetates 4a - 4f with the Bredereck reagent. This approach was used for the synthesis of biologically active natural compounds 1a - 1f, through a three-step procedure starting from the corresponding phenols.
- Jerezano, Alberto,Jimenez, Fabiola,Del Carmen Cruz, Maria,Montiel, Luisa E.,Delgado, Francisco,Tamariz, Joaquin
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p. 185 - 198
(2011/04/17)
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- Design, synthesis, and biological evaluation of coumarin derivatives tethered to an edrophonium-like fragment as highly potent and selective dual binding site acetylcholinesterase inhibitors
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A large series of substituted coumarins linked through an appropriate spacer to 3-hydroxy-N,N-dimethylanilino or 3-hydroxy-N,N,N-trialkylbenzaminium moieties were synthesized and evaluated as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors. The highest AChE inhibitory potency in the 3-hydroxy-N,N-dimethylanilino series was observed with a 6,7-dimethoxy-3-substituted coumarin derivative, which, along with an outstanding affinity (IC50=0.236 nm) exhibits excellent AChE/BChE selectivity (SI>300 000). Most of the synthesized 3-hydroxy-N,N,N- trialkylbenzaminium salts display an AChE affinity in the sub-nanomolar to picomolar range along with excellent AChE/BChE selectivities (SI values up to 138 333). The combined use of docking and molecular dynamics simulations permitted us to shed light on the observed structure-affinity and structure-selectivity relationships, to detect two possible alternative binding modes, and to assess the critical role of π-π stacking interactions in the AChE peripheral binding site.
- Pisani, Leonardo,Catto, Marco,Giangreco, Ilenia,Leonetti, Francesco,Nicolotti, Orazio,Stefanachi, Angela,Cellamare, Saverio,Carotti, Angelo
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experimental part
p. 1616 - 1630
(2011/11/29)
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- Yb(OTf)3-catalyzed reactions of 5-alkylidene Meldrum's acids with phenols: One-pot assembly of 3,4-dihydrocoumarins, 4-chromanones, coumarins, and chromones
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The Yb(OTf)3-catalyzed annulation reactions of phenols with 5-alkylidene Meldrum's acids enabled the synthesis of structurally diverse heterocycles in high isolated yields. A series of 4-substituted 3,4-dihydrocoumarins, 2,2-disubstituted 4-chromanones, coumarins, and 2-substituted chromones were readily and efficiently assembled, including the naturally occurring coumarins citropten, scoparone, and ayapin. Addition of phenols to biselectrophilic 5-alkylidene Meldrum's acids proceeded through two distinct multibond-forming modes: Friedel-Crafts C-alkylation/(O-acylation and Friedel-Crafts C-acylation/O-alkylation. The regioselectivity of the catalytic annulation reaction was controlled by the degree of substitution on the alkylidene moiety.
- Fillion, Eric,Dumas, Aaron M.,Kuropatwa, Bryan A.,Malhotra, Neil R.,Sitler, Tamsyn C.
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p. 409 - 412
(2007/10/03)
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- Reactions of psoralen radical cations with biological substratest
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The reactions of several psoralen and coumarin radical cations with biological substrates such as nucleotides, amino acids and alkenes that serve as models for unsaturated fatty acids have been examined. The radical cations were generated by laser photoionization of the parent psoralen or coumarin in aqueous buffer in most cases. Easily oxidized substrates such as tyrosine, tryptophan and guanosine monophosphate react with the 8-methoxypsoralen and several methoxy-substituted coumarin radical cations with rate constants in excess of 2 × 109 M-1 s-1. In each case reaction occurs via electron transfer, as demonstrated by the observation of quencher-derived radical cations or radicals by transient absorption spectroscopy. For other substrates such as histidine, methionine and adenosine monophosphate the measured rate constants are significantly slower and vary with the oxidation potential of both the parent psoralen or coumarin and the quencher, again indicative of electron transfer reactivity. Most of the alkenes studied also react with the psoralen or coumarin radical cations via electron transfer, although there is some evidence for addition for linoleic acid. Product studies carried out using both lamp and laser irradiation in the presence of deoxyguanosine as a radical cation trap lead to the formation of characteristic base-derived Type-I (electron transfer) products. This lends support to our previous hypothesis that photoionization occurs via a monophotonic process and is thus relevant to conditions used in clinical phototherapeutic applications of psoralens. The results demonstrate the relevance of electron transfer chemistry to the use of psoralens and related compounds as photoactivated drugs.
- Wood, Paul D.,Mnyusiwalla, Anisa,Chen, Lie,Johnston, Linda J.
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p. 155 - 162
(2007/10/03)
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- Improved Synthesis of Esculetin
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An improved synthesis of esculetin (6,7-dihydroxycoumarin) and 3-hydroxy-6,7-dimethoxycoumarin (4a) is described.
- Jackson, Yvette A.
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p. 1979 - 1986
(2007/10/02)
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- Claisen Rearrangement of Z- and E-4,5-Dimethoxy-2-prenyloxycinnamic Acids: Formation of Scopoletin, Suberosin and 3-Prenylscoparone
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The Z- and E-4,5-dimethoxy-2-prenyloxycinnamic acids (2 and 6), obtained by ring opening of 6,7-dimethoxycoumarin (1; scoparone) under different conditions followed by prenylation, undergo Claisen rearrangement to give scopoletin (3) together with suberosin (4) and 3-prenylscoparone (7), respectively.The steric and sustituent effects have been discussed.
- Koul, S. K.,Taneja, S. C.,Dhar, K. L.
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p. 574 - 575
(2007/10/02)
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- CHROMONES AND COUMARINS FROM SKIMMIA LAUREOLA
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The isolation and characterisation of chromones and coumarins, including the new chromone, skimminin, from S. laureola is reported. - Key Word Index: Skimmia laureola; Rutaceae; chromones; skimminin; coumarins; linear furanocoumarins.
- Razdan, T. K.,Qadri, B.,Harkar, S.,Waight, E. S.
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p. 2063 - 2070
(2007/10/02)
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- An Improved Synthesis of Naturally Occuring Coumarins: Synthesis of Herniarin, Scoparone and 7-Methoxy-6-methylcoumarin
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Vilsmeier-Haack reaction of methoxybenzenes (1a-c) gives aldehydes (2a-c), which on demethylation with AlCl3 in CH2Cl2 yield the hydroxyaldehydes (3a-c).These hydroxyaldehydes on reaction with carbethoxymethylenetriphenylphosphorane furnish the naturally occuring coumarins, herniarin (4a), scoparone (4b) and 7-methoxy-6-methylcoumarin (4c).
- Mali, R. S.,Yadav, V. J.,Zaware, R. N.
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p. 759 - 760
(2007/10/02)
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