- Microwave-assisted synthesis of derivatives of khellinone under phase-transfer catalytic conditions
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The microwave-assisted synthesis of four new 5-acetyl-4,7-dimethoxy-6- hydroxybenzofuran (khellinone) analogs is described. The structures of the obtained derivatives in the solid state are evaluated on the basis of 13C CP/MAS NMR spectra and theoretical calculations at DFT level. A single crystal X-ray diffraction structure is presented for 8-acetyl-7-hydroxy- 4-methylcoumarin. 1,4-Bis(5-acetyl-4,7-dimethoxybenzofuran-6-yloxy)butane was evaluated for potential anticancer activity in an in vitro screening panel of 60 human tumor cell lines. Selected leukemia, non-small cell lung cancer, CNS, melanoma, ovarian, and breast cancer cell lines were sensitive to this compound.
- Hejchman, Elzbieta,Maciejewska, Dorota,Wolska, Irena
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- 5-HT1A and 5-HT2A receptors affinity, docking studies and pharmacological evaluation of a series of 8-acetyl-7-hydroxy-4-methylcoumarin derivatives
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In this work we describe the synthesis, docking studies and biological evaluation of a focused library of novel arylpiperazinyl derivatives of 8-acetyl-7-hydroxy-4-methylcoumarin. The new compounds were screened for their 5-HT1A and 5-HT2A receptor affinity. Among the evaluated compounds, six displayed high affinities to 5-HT1A receptors (4a-0.9 nM, 6a-0.5 nM, 10a-0.6 nM, 3b-0.9 nM, 6b-1.5 nM, 10b-1 nM). Compound 6a and 10a bearing a bromo- or methoxy- substituent in ortho position of the piperazine phenyl ring, were identified as potent antagonists of the 5-HT1A receptors. In the tail suspension test, mice injected with 6a showed a dose-dependent increase in depressive-like behavior that was related to a decrease in locomotor activity. Compound 10a did not decrease or prolong immobility time nor did it affect home cage activity. Molecular docking studies using 5-HT1A and 5-HT2A homology models revealed structural basis of the high affinity of ortho-substituted derivatives and subtle changes in amino acid interactions patterns depending on the length of the alkyl linker.
- Ostrowska, Kinga,Grzeszczuk, Dawid,G?uch-Lutwin, Monika,Grybo?, Anna,Siwek, Agata,Le?niak, Anna,Sacharczuk, Mariusz,Trzaskowski, Bartosz
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- Antitumor and multikinase inhibition activities of some synthesized coumarin and benzofuran derivatives
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Two new series of coumarin and benzofuran derivatives were designed, synthesized, and assessed for their in vitro and in vivo antitumor activities against breast cancer. Compounds 8, 9, 14, 15, and 17 exhibited the best antiproliferative activities (IC50: 0.07?2.94 μM) against the MCF-7 cell line, compared with lapatinib (IC50: 4.69 μM). Compound 14, with the most potent cytotoxic activity against MCF-7 cells, was capable of enhancing preG1 apoptosis and triggering cell cycle arrest at the G2/M phase. The kinase inhibitory activity of compound 14 against a panel of 22 kinases was examined to reveal multikinase inhibition within ?39% to ?97%. Furthermore, compound 14 exhibited potent in vivo Ehrlich (mammary adenocarcinoma) tumor regression, positive caspase-3, and negative EGFR immunoreaction, and was capable of elevating the catalase level. The physicochemical properties and pharmacokinetic parameters of compound 14 were investigated in silico for its druglikeness.
- Abd Elmageed, Zakaria Y.,Abdelhafez, Omaima M.,Ahmed, Eman Y.,Ahmed, Yasmine H.,Ali, Hamed I.,El-Telbany, Rania Farag A.,Serry, Aya M.,Zaafar, Dalia
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- (E)-4 - methyl -7 - hydroxyl -8 - (3 - (ferrocenyl) acryloyl) coumarin as well as preparation method and application thereof
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The invention discloses (E)-4 - methyl -7 - hydroxyl -8 - (3 - (ferrocenyl) acryloyl) coumarin as well as a preparation method and application thereof, and (E)-4 - methyl -7 - hydroxyl -8 - (3 - (ferrocenyl) acryloyl) coumarin has the following structural formula. The present disclosure uses resorcinol as a raw material and condenses with Knoevenagal. 7 (7) Fries-methyl 8 hydroxyl E (-4 - 3 -8 - (ferrocenyl) acryloyl) coumarin is added into ABTBTBTS?, DPPHPHI and galvinvinvinvinylisopropyl -7 -) coumarin to exhibit excellent antioxidation activity, and the antioxidant performance is E superior -4 - to -7 - the -8 - corresponding 3 - ferrocenyl chalcone and coumarin-based chalcone, and has potential application values and is excellent in anti-oxidation activity and excellent in anti-oxidation performance.
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Paragraph 0025; 0037; 0058; 0061; 0063; 0066
(2021/10/20)
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- Synthesis and biological evaluation of new coumarin derivatives as cytotoxic agents
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New coumarin derivatives 9a–f, 10a–e, and 11a–f were synthesized and evaluated for their cytotoxic activity against a human breast cancer cell line (MCF-7). All compounds exhibited good activity in the nanomolar range, using doxorubicin and erlotinib as positive controls. The most active compound 9d with IC50 of 21 nM was tested against the HCT-116, HepG-2, A549, and SGC-7901 cell lines, with IC50 values of 0.021, 0.170, 0.028, and 0.11 μM, respectively. Compound 9d was further investigated for its ability to suppress the expression of epidermal growth factor receptor (EGFR). Compound 9d decreased the concentration of EGFR by 87%, using erlotinib as a positive control. A docking study revealed similar or higher scores than for erlotinib and similar binding poses providing interactions with the hinge region of the tyrosine kinase (TK). Besides the effect on expression, this in silico investigation predicts the possibility of direct binding between the new coumarin derivatives and the EGFR TK. Moreover, computational calculation for ADME properties for the most active compounds 9d, 9e, 10c, and 11c revealed the expected high gastrointestinal tract absorption, moderate water solubility with no central nervous system toxicity, and druglikeness.
- Ragab, Fatma A.,Eissa, Amal A. M.,Fahim, Samar H.,Salem, Mohammad A.,Gamal, Mona A.,Nissan, Yassin M.
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- A multi-responsive crown ether-based colorimetric/fluorescent chemosensor for highly selective detection of Al3+, Cu2+ and Mg2+
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A novel multi-response chemosensor L based on coumarin-chalcone-crown ether was designed and synthesized, which exhibited a high selectivity for the colorimetric detecting Al3+ and Cu2+ and fluorescent recognizing Al3+ and Mg2+ in ethanol. L can monitor Al3+ and Cu2+ via distinct color changes from a slight yellow to pink and to orange, respectively. The sensor L can also monitor Al3+ and Mg2+ by fluorescence emission responses at 592 nm and 547 nm with low detection limits of 0.31 μM and 0.23 μM, respectively. The selectivity of L toward Al3+, Cu2+ and Mg2+ was not interfered by a large number of coexisting ions and was found to be reversible. By means of spectrometric titration, Job's plot, mass spectrometry, 1H NMR titration and IR spectroscopy analysis, it was unanimously confirmed that the sensor L had a stoichiometric ratio of 1:1 with Cu2+ and Mg2+, and 1:2 with Al3+. The order of the stability of the complexes formed by L and Al3+, Cu2+, Mg2+ was as follows: L-Al3+ > L-Cu2+ > L-Mg2+. At the same time, some possible bonding modes and sensing mechanisms were further proposed, and the optimized structure of the sensor L and its sensing mechanism for Al3+, Cu2+ and Mg2+ were confirmed by the calculations of DFT/B3LYP and TD-DFT methods in a suite of Gaussian 09 programs.
- Zhang, Qiang,Ma, Ruifang,Li, Zhuying,Liu, Zizhong
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- Synthesis of pyrazole-4-carbaldehyde derivatives for their antifungal activity
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A series of pyrazole-4-carbaldehyde containing coumarin derivatives (9a–l) were achieved starting from substituted 6-hydroxy-4-methyl coumarins in a facial manner by Vilsmeier–Haack Formylation reaction in good yields, and their chemical structures were determined by Fourier transform infrared, 1H, 13C-nuclear magnetic resonance and mass spectroscopic techniques. Compounds 9a–l were docked into monoamine oxidase from Aspergillus niger and shown strong π-stacking interactions with the cage forming amino acids of Trp430 and Phe466, and were also further evaluated against antifungal activity on Aspergillus niger by taking Clotrimazole as standard. Out of twelve synthesized compounds 9a, 9b, 9g, and 9h were showed good and 9c, 9d, 9e, 9i, 9j, and 9k were showed moderate antifungal activity.
- Reddy, Vadiyala Naveen,Yamini, Lingala,Rao, Yerrabelly Jayaprakash,Rao, Chitneni Prasad
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p. 1664 - 1674
(2017/06/27)
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- Synthesis and biological evaluation of novel coumarin derivatives as potential antimicrobials agents
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Objective: Synthesize new series of 7-hydroxy-4-methylcoumarin and 7-alkoxy-4-methylcoumarin derivatives featuring thiosemicarbazone or thiazolidin-4-one moieties and to evaluate their antimicrobial activity against two strains of Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), two Gram-negative bacteria (Escherichia Coli and Pseudomonas aeruginosa), and Candida albicans. Methods: Preparation of the new coumarin derivatives was done by adopting Pechmann condensation and attaching different isothiocyanates to give coumarin-thiosemicarbazone hybrids. Thiosemicarbazones were cyclized into thiazolidine-4-ones using chloroacetic acid or diethyl bromo malonate. Results: Compounds VIb, Xb, XIVb, and XVc gave the highest inhibition zones (>20 mm) against Staphylococcus aureus. Their MIC (minimum inhibitory concentration) values ranging from 0.19-0.36 μg/ml were better than the reference drug tobramycin with MIC= 2μg/ml. Conclusion: The newly synthesized compounds with the 7-hydroxyl group showed better antimicrobial activity than those with the 7-alkoxy groups.
- Amin, Kamilia M.,Abou-Seri, Sahar M.,Abdelnaby, Rana M.,Rateb, Heba S.,Khalil, Mahmoud A. F.,Hussein, Mohamed M.
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p. 109 - 116
(2016/04/10)
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- Synthesis and photooxygenation of linear and angular furocoumarin derivatives as a hydroxyl radical source: Psoralen, pseudopsoralen, isopseudopsoralen, and allopsoralen
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Synthesis of linear and angular furocoumarins with new skeleton structure of potential photobiological feature interest was carried out through Williamson reaction of hydroxycoumarins with 3-chloro-2-butanone followed by cyclization with polyphosphoric acid or by heating in a strongly alkaline solution. The photooxygenation reactions of synthesized furocoumarins were performed in chloroform and in the presence of tetraphenylporphyrin as singlet oxygen sensitizer (1O2). The photooxygenation reactions afforded the photocleaved product through [2 + 2] cycloaddition and the photooxygenated products through ene reaction and [4 + 2] cycloaddition. The photoproducts were isolated and fully characterized by spectral analyses.
- Elgogary, Sameh Ramadan,Hashem, Neveen Mohamed,Khodeir, Mohamed Nabeel
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p. 506 - 512
(2015/03/30)
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- Synthesis of two-photon active cinnamoyl coumarins for high-contrast imaging of cancer cells and their photophysical characterization
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A series of two-photon (TP) active 4-dimethylaminocinnamoyl coumarins were synthesized. These compounds exhibit red shift in absorption and considerable Stokes shift in emission spectra in comparison to the parent coumarin. Large TP absorption cross-sections were measured for all the coumarins in dilute solutions. A correlation between the chemical structure and TP characteristics was established. TP confocal microscopy revealed that these coumarin derivatives can be internalized by cancer cells rendering them a potential candidate as a label in TP confocal imaging.
- Yadav, Preeti,Satapathi, Soumitra,Kumari, Meena,Chaturvedi, Akanksha,Li, Lian,Samuelson, Lynne A.,Kumar, Jayant,Sharma, Sunil K.
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- Coumarin moiety can enhance abilities of chalcones to inhibit DNA oxidation and to scavenge radicals
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Coumarin and chalcone are naturally occurring compounds, and coumarin as a functional group was combined with chalcone in this work, aiming to test the inhibitory effects of coumarin-substituted chalcones on the oxidation of DNA and on scavenging radicals. It was found that the antioxidant activity of hydroxyl group attaching to coumarin can be increased by hydroxyl groups attaching to chalcone. The double hydroxyl groups at adjacent position exhibited high abilities to inhibit Cu2+/glutathione-induced oxidation of DNA and to trap 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS+) as well as 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH). Especially, the double hydroxyl groups in chalcone were able to protect DNA against 2,2′-azobis(2-amidinopropanehydrochloride) (AAPH)-induced oxidation significantly. On the other hand, the hydroxyl group attaching to coumarin exhibited high ability to inhibit OH-induced oxidation of DNA. Therefore, coumarin-appended chalcones exhibited higher antioxidant effectiveness with only single or double phenolic hydroxyl groups contained.
- Xi, Gao-Lei,Liu, Zai-Qun
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p. 8397 - 8404
(2015/03/04)
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- Synthesis and antiproliferative and c-Src kinase inhibitory activities of cinnamoyl-and pyranochromen-2-one derivatives
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A series of 6-and 8-cinnamoylchromen-2-one and dihydropyranochromen-2-one derivatives were synthesized and their antiproliferative activities were evaluated against three human cancer cell lines, i.e., ovarian adenocarcinoma (SK-OV-3), leukemia (CCRF-CEM), and breast carcinoma (MCF-7). In general, 8-cinnamoylchromen-2-one derivatives were found to have higher antiproliferative activity against the cancer cells when compared with 6-cinnamoyl analogues. Among all of the hybrid chromen-2-one-chalcone/flavanone compounds, a 7-hydroxy-8-cinnamoylchromen-2-one derivative 35 was found to be consistently active against all the cancer cell lines and inhibited the cell proliferation of SK-OV-3, CCRF-CEM, and MCF-7 by 63%, 50%, and 43%, respectively, at a concentration of 50 μmol/L after 72 h of incubation. This compound also exhibited the highest Src kinase inhibition (IC50 = 14.5 μmol/L). Structure-activity relationship studies provided insights for designing the next generation of chromen-2-one-chalcone hybrid prototypes and the development of new leads as anticancer agents and (or) Src kinase inhibitors.
- Chand, Karam,Shirazi, Amir Nasrolahi,Yadav, Preeti,Tiwari, Rakesh K.,Kumari, Meena,Parang, Keykavous,Sharma, Sunil K.
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p. 741 - 754
(2013/08/23)
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- Synthesis and biological evaluation of novel formyl-pyrazoles bearing coumarin moiety as potent antimicrobial and antioxidant agents
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A series of coumarin appended formyl-pyrazoles 14-18 were synthesized by a simple and accessible approach. The reaction of 8-acetyl-4-methyl-7-hydroxy coumarin 3 and phenyl hydrazine hydrochlorides 4-8 produces the intermediate compounds 8-acetyl-4-methyl
- Renuka, Nagamallu,Ajay Kumar, Kariyappa
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p. 6406 - 6409
(2013/11/19)
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- Substrate specificity of acetoxy derivatives of coumarins and quinolones towards Calreticulin mediated transacetylation: Investigations on antiplatelet function
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Calreticulin transacetylase (CRTAase) is known to catalyze the transfer of acetyl group from polyphenolic acetates (PA) to certain receptor proteins (RP), thus modulating their activity. Herein, we studied for the first time the substrate specificity of CRTAase towards N-acetylamino derivatives of coumarins and quinolones. This study is endowed with antiplatelet action by virtue of causing CRTAase catalyzed activation of platelet Nitric Oxide Synthase (NOS) by way of acetylation leading to the inhibition of ADP/Arachidonic acid (AA)-dependent platelet aggregation. Among all the N-acetylamino/acetoxy coumarins and quinolones screened, 7-N-acetylamino-4-methylcoumarin (7-AAMC, 17) was found to be the superior substrate to platelet CRTAase and emerged as the most promising antiplatelet agent both in vitro and in vivo. Further it caused the inhibition of cyclooxygenase-1 (Cox-1) resulting in the down regulation of thromboxane A2 (TxA2), modulation of tissue factor and the inhibition of platelet aggregation. It was also found effective in the inhibition of LPS induced pro-thrombotic conditions.
- Kathuria, Abha,Priya, Nivedita,Chand, Karam,Singh, Prabhjot,Gupta, Anjali,Jalal, Sarah,Gupta, Shilpi,Raj, Hanumantharao G.,Sharma, Sunil K.
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experimental part
p. 1624 - 1638
(2012/05/04)
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- Co(II), Ni(II) and Cu(II) complexes with coumarin-8-yl Schiff-bases: Spectroscopic, in vitro antimicrobial, DNA cleavage and fluorescence studies
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A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial (Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities (Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.
- Patil, Sangamesh A.,Unki, Shrishila N.,Kulkarni, Ajaykumar D.,Naik, Vinod H.,Badami, Prema S.
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experimental part
p. 1128 - 1136
(2011/10/03)
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- Anti-influenza drug discovery: Structure-activity relationship and mechanistic insight into novel angelicin derivatives
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By using a cell-based high throughput screening campaign, a novel angelicin derivative 6a was identified to inhibit influenza A. (H1N1) virus induced cytopathic effect in Madin-Darby canine kidney cell culture in low micromolar range. Detailed structure-activity relationship studies of 6a revealed that the angelicin scaffold is essential for activity in pharmacophore B, while meta-substituted phenyl/2-thiophene rings are optimal in pharmacophore A and C. The optimized lead 4-methyl-9-phenyl-8-(thiophene-2-carbonyl)-furo[2,3-h] chromen-2-one (8g, IC50 = 70 nM) showed 64-fold enhanced activity compared to the high throughput screening (HTS) hit 6a. Also, 8g was found effective in case of influenza A (H3N2) and influenza B virus strains similar to approved anti-influenza drug zanamivir (4). Preliminary mechanistic studies suggest that these compounds act as anti-influenza agents by inhibiting ribonucleoprotein (RNP) complex associated activity and have the potential to be developed further, which could form the basis for developing additional defense against influenza pandemics.
- Yeh, Jiann-Yih,Coumar, Mohane Selvaraj,Horng, Jim-Tong,Shiao, Hui-Yi,Kuo, Fu-Ming,Lee, Hui-Ling,Chen, In-Chun,Chang, Chun-Wei,Tang, Wen-Fang,Tseng, Sung-Nain,Chen, Chi-Jene,Shih, Shin-Ru,Hsu, John T.-A.,Liao, Chun-Chen,Chao, Yu-Sheng,Hsieh, Hsing-Pang
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experimental part
p. 1519 - 1533
(2010/08/20)
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- Anti-AIDS agents 82: Synthesis of seco-(3′R,4′R)-3′,4′-di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK) derivatives as novel anti-HIV agents
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Thirteen novel seco-DCK analogs (4-16) with several new skeletons were designed, synthesized and screened for in vitro anti-HIV-1 activity. Among them, three compounds (5, 13, and 16) showed moderate activity, and compound 9 exhibited the best activity with an EC50 value of 0.058 μM and a therapeutic index (TI) of 1000. The activity of 9 was better than that of 4-methyl DCK (2, EC50: 0.126 μM, TI: 301.2) in the same assay. Additionally, 9 also showed antiviral activity against a multi-RT inhibitor-resistant strain (RTMDR), which is insensitive to most DCK analogs. Compared with 2, compound 9 has a less complex structure, fewer hydrogen-bond acceptors, and a reduced log P value. Therefore, it is likely to exhibit better ADME, and appears to be a promising new lead for further development as an anti-HIV candidate.
- Tang, Jian,Qian, Keduo,Zhang, Bei-Na,Chen, Ying,Xia, Peng,Yu, Donglei,Xia, Yi,Yang, Zheng-Yu,Chen, Chin-Ho,Morris-Natschke, Susan L.,Lee, Kuo-Hsiung
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experimental part
p. 4363 - 4373
(2010/09/12)
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- Pyranocoumarins: A new class of anti-hyperglycemic and anti-dyslipidemic agents
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A series of pyranocoumarin derivatives were synthesized and evaluated in vivo for their anti-hyperglycemic as well as anti-dyslipidemic activities. Compounds 7a, 7c, 8a, 8b, 8c, 8e and 8f have shown promising anti-hyperglycemic activities in sucrose loaded model (SLM) as well as sucrose challenged streptozotocin induced diabetic rat model (STZ). Compounds 8a and 8b were showing 38.0% and 42.0% blood glucose lowering activity in db/db mice model. In vitro anti-hyperglycemic activity evaluation exhibited that compounds 8a (IC50 = 24.5 μM) and 8b (IC50 = 36.2 μM) are potential PTP-1B inhibitors thereby revealing their possible mechanism of anti-diabetic action. Compounds 7a, 7b, 8a, 8b, 8d, 8e and 8f have shown significant anti-dyslipidemic activity in triton induced dyslipidemia in rats.
- Kumar, Atul,Maurya, Ram Awatar,Sharma, Siddharth,Ahmad, Pervez,Singh,Bhatia, Gitika,Srivastava, Arvind K.
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supporting information; experimental part
p. 6447 - 6451
(2010/05/02)
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- Synthesis and biological activity of meso-tetrakis (2,10-dioxo-2H, 10H-pyrano [2,3-f] chromene-9-yl) porphyrins
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Synthesis of meso-tetrakis (2, 10-dioxo-2H, 10H-pyrano[2,3-f] chromene-9-yl) porphyrins are synthesized directly by reaction of pyrrole with substituted 4-methyl-2,10-dioxo-2H, 10H-pyrano[2,3-f]chromene-9-carbaldehydes in dichloromethane / acid media. The aldehyde's molar ratio was controlled to optimize the synthesis and purification of the desired porphyrins. This new series of porphyrins was characterized by TLC, Mass Spectrometry (FAB mass), 1H NMR, UV and IR ARKAT.
- Kumar, V. Naveen,Thirupathi Reddy,Narasimhareddy,Rajitha,De Clercq
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p. 181 - 188
(2013/09/12)
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- BENZOPYRONE COMPOUNDS, PREPARATION METHOD AND USE THEREOF
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The invention relates to pesticide and bactericide, specifically to the benzopyrone compounds and its preparation method and use thereof. The benzopyrone compounds of the invention having general formula (I): The present invention, having good pesticide activity and broad bactericide activity, applied for controlling various pests in plants such as army worm, diamond backmoth and aphid, carmine spider mite, two-spotted spider mite, ladybeetle, mites and mosquito larvae. Various disease in plants can be controlled by the invention and that of grape downy mildew, rice sheath and culm blight, rice blast, tomato early blight, tomato late blight ,wheat leaf rust, wheat leaf blotch, wheat powdery mildew, cucumber powdery mildew, cucumber downy mildew, cucumber grey mold and so on.
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Page/Page column 19
(2008/06/13)
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- Intermolecular character of the Fris rearrangement in the series of acyloxycoumarins
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In the study of the Fris rearrangement in the series of 7-and 4-acyloxycoumarins we obtained certain data indicating intermolecular character of the rearrangement. The Fris rearrangement of a mixture of 7-benzoyloxy-4-metylcoumarin and 7-acetoxycoumarin results in formation of four reaction products in approximately equal molar ratio. Also, four products were obtained in the Fris rearrangement of 7-and 4-acyloxycoumarins in the presence of hydroxycoumarins. The Fris rearrangement of acyloxycoumarins in the presence of m-xylene at acylcoumarin-m-xylene ratio of 1:6 leads to the corresponding hydroxycoumarins and acylated m-xylenes. Intermediate formation of acylium ions was also detected by evolution of carbon monooxide at the Fris rearrangement of 7-pyvaloyloxy-and 7-isobutyryloxy-4-methylcoumarins. A product of intermolecular migration, 3-acetyl-4-hydoxy-6-methylcoumarin, was discovered also in the rearrangement of 4-acetoxycoumarin in the presence of 4-hydoxy-6-methylcoumarin catalyzed by phosphorus oxychloride.
- Kravchenko,Chibisova,Traven'
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p. 899 - 909
(2007/10/03)
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- New synthetic procedure for oxazolo[4,5-h]coumarins
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Oximes of 8-acyl-7-hydroxycoumarins when treated with excess acetic anhydride in the presence of concentrated sulfuric acid afford oxazolo[4,5-h]coumarins in good yield. Similar treatment without sulfuric acid results in O,N-diacetates of oximes of 8-acyl
- Chibisova,Solov'eva,Pozhidaeva,Manaev,Traven'
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p. 263 - 268
(2007/10/03)
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- Claisen rearrangement of 3-bromo-, 3,6-dibromo-, 3,8-dibromo- and 8- iodo/aminomethyl/acetyl-7-allyloxy-4-methylcoumarins
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7-Hydroxy-4-methylcoumarin 1 has been brominated under different conditions to obtain the corresponding 3-bromo-2; 3,6-dibromo- 4; 3,8- dibromo- 3; and 3,6,8-tribromo- 8 derivatives. The 24 are allylated and subjected to Claisen rearrangement in N,N-DMA when only 8-allyl-7-hydroxy-4- methylcoumarin 13 is obtained. The Claisen rearrangement of 8-iodo and 8- aminomethyl coumarins also give 13. In all these rearrangements the 8- substituent is removed and the migration takes place at the 8-position. The N,N-DMA serves as the scavenger for the substituent lost. The Claisen rearrangement of 8-acetyl-7-allyloxy-4-methylcoumarin gives 8-acetyl-6-allyl- 7-hydroxy-4-methylcoumarin, in which the acetyl group remains intact.
- Ghantwal,Samant
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p. 1242 - 1247
(2007/10/03)
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- 4'-Methylangelicins: New potential agents for the photochemotherapy of psoriasis
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Three derivatives of angelicin (1) [4'-methyl-, 4,4'-dimethyl-, and 4',5-dimethylangelicin (2a-c)] have been prepared with the aim of obtaining new agents for the photochemotherapy of psoriasis. These compounds form a complex in the dark with DNA that shows an affinity for the macromolecule higher than that of the parent angelicin (1). A correlation between their octanol/water partition coefficients and the association constants of the complexes has been observed. Compounds 2a-c photobind to DNA to a much higher extent than 1 and also more effectively than 8-methoxypsoralen (8-MOP), taken as reference compound. When activated with UV-A, the three compounds strongly inactivate T2 phage and inhibit epidermal DNA synthesis in mice. Moreover, they show a mutagenic activity markedly lower than that of 8-methoxypsoralen on Escherichia coli wild-type strain. Due to its lack of skin phototoxicity, its low mutagenic activity, and its antiproliferative activity, 2c was chosen for clinical evaluation. It proved to be effective in clearing psoriasis in two patients.
- Dall'Acqua,Vedaldi,Bordin,Baccichetti,Carlassare,Tamaro,Rodighiero,Pastorini,Guiotto,Recchia,Cristofolini
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p. 870 - 876
(2007/10/02)
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