- A new method for annulation of the α-pyrone ring
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New derivatives of coumarin, containing annulated α-pyrone rings, were obtained by reaction of the borate complexes of three isomeric acyl(hydroxy)coumarins with acid anhydrides. It was shown that the borate complex of 3-acetyl-4-hydroxy-2-pyrone also condenses with acetic anhydride to form a derivative containing a new annulated α-pyrone ring.
- Traven,Voevodina,Manaev,Podkhalyuzina
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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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- (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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- 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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- Design, synthesis, and biological activity of Schiff bases bearing salicyl and 7-hydroxycoumarinyl moieties
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Abstract: 18 (11 novel) Schiff bases, derivatives of salicylaldehyde, 2-hydroxyacetophenone, and 6-acetyl-, 8-acetyl-, and 8-formyl-7-hydroxy-4-methylcoumarin were synthesized and characterized by their spectral studies. 6-Acetyl-7-hydroxy-4-methylcoumarin was prepared by novel method under microwave assistance. These Schiff bases were evaluated for antibacterial activities against 12 bacterial and six fungi strains in vitro. N-(3,5-Dichloro-2-hydroxybenzylidene)-4-aminobenzenesulfonic acid sodium salt proved to be the most active against Staphylococcus aureus and MRSA strains (MIC 0.0194?μmol/cm3). The substitution pattern, two chlorine atoms in the salicylidene ring and the SO3Na group, is probably the most beneficial for the activity against Gram-(+) bacteria strains. All Schiff bases were evaluated for cancer efficacy against CFPAC-1 and HeLa cell cultures originating from human pancreas cancer or human cervical cancer. Schiff bases derived from salicylaldehyde are highly effective in pancreas and cervical cancer cells; however, they demonstrate also substantial toxicity towards NIH3T3 cells. Derivatives of coumarin contain three highly selective compounds: 7-hydroxy-8-[(4-methoxyphenylimino)methyl]-4-methyl-2H-chromen-2-one, N-[(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene]-4-aminobenzenesulfonic acid sodium salt, and 7-hydroxy-8-[1-(4-hydroxyphenylimino)ethyl]-4-methyl-2H-chromen-2-one suggesting more promising potential of the second group of substances.
- Hejchman, El?bieta,Kruszewska, Hanna,Maciejewska, Dorota,Sowirka-Taciak, Barbara,Tomczyk, Magdalena,Sztokfisz-Ignasiak, Alicja,Jankowski, Jan,M?ynarczuk-Bia?y, Izabela
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p. 255 - 266
(2019/01/16)
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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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- An improved helferich method for the α/β-stereoselective synthesis of 4-methylumbelliferyl glycosides for the detection of microorganisms
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An improved Helferich method is presented. It involves the glycosylation of 4-methyl-umbelliferone with glycosyl acetates in the presence of boron trifluoride etherate combined with triethylamine, pyridine, or 4-dimethylaminopyridine under mild conditions, followed by deprotection to give fluorogenic 4-methylumbelliferyl glycoside substrates. Due to the use of base, the glycosylation reaction proceeds more easily, is uncommonly α- or β-stereoselective, and affords the corresponding products in moderate to excellent yields (51%-94%) under appropriate conditions.
- Wei, Xianhu,Ma, Yanxia,Wu, Qingping,Zhang, Jumei,Cai, Zhihe,Lu, Mianfei,Ferro, Vito
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p. 21681 - 21699
(2016/01/25)
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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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- Manganese(III)-mediated direct Csp2-H radical trifluoromethylation of coumarins with sodium trifluoromethanesulfinate
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Mn(OAc)3-mediated direct Csp2-H radical trifluoromethylation of coumarins with CF3SO2Na (Langlois reagent) to afford selective 3-trifluoromethyl coumarins in moderate to good yields is described. This methodology can also be applied to the trifluoromethylation of quinolinones and pyrimidinones. The Royal Society of Chemistry 2014.
- Cao, Xiao-Hui,Pan, Xiangqiang,Zhou, Peng-Jun,Zou, Jian-Ping,Asekun, Olayinka Taiwo
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supporting information
p. 3359 - 3362
(2014/03/21)
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- Synthesis, spectral characterization and α-chymotrypsin activity of 7-O-substituted derivatives of 7-hydroxy-4-methyl-1-benzopyran-2-one
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In this work, a series of O-alkyl/arenyl/acyl substituted derivatives of 7-hydorxy-4-methyl-1-benzenpyran-2-one (3a-l) was synthesized. The parent compound 7-hydroxy-4-methyl-1-benzenpyran-2-one (1) was geared up by the coupling of resorcinol (a) with ethylacetoacetate (b) in the presence of conc. sulphuric acid. Further, O-substituted derivatives of parent compound were prepared by treating with different electrophiles (2a-l) using sodium hydride as base and DMF as a solvent. The structure of these synthesized compounds were characterized by IR, EI-MS and 1H NMR. These derivatives were also screened against α-chymotrypsin enzyme to check their enzyme inhibition activity. All the compounds displayed a-chymotrypsin activity to varying degree.
- Aziz-Ur-Rehman,Ilyas, Tehseen,Abbasi, Muhammad Athar,Nafeesa, Khadija,Khaliq, Shaista,Rubab, Kaniz,Hussain, Ghulam,Khurshid, Shazia,Ahmad, Irshad
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p. 326 - 330
(2014/06/09)
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- Synthesis and anti-bacterial activity of novel dihydrochromeno[8,7-e][1,3] oxazine-2(8H)-thiones
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A novel series of sulfur-containing dihydrochromeno[8,7-e][1,3]oxazine- 2(8H)-thiones has been synthesized through an eco-friendly Mannich-type condensation cyclization reaction of 7-hydroxy-4-methyl-2-thiocoumarin or 6-chloro-7-hydroxy-4-methyl-2-thiocoumarin with formaldehyde and primary amines in water at 80-90°C for 2 h. All the synthesized compounds were screened for their in vitro anti-bacterial efficacy against two Gram-positive and three Gram-negative bacterial strains by using the disc diffusion method. The compound (8c) was found to be most potent with the zone of inhibition of 16 and 15 mm against Staphylococcus aureus ATCC 2937 and Klebsiella pneumoniae ATCC 31488, respectively.
- Mathew, Bijoy P.,Aggarwal, Nisha,Kumar, Rajesh,Nath, Mahendra
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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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- Tris(pentafluorophenyl)borane catalyzed acylation of alcohols, phenols, amines, and thiophenols under solvent-free condition
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The acylation of alcohols, phenols, amines, and thiophenols was accomplished with 0.5 mol % of tris(pentafluorophenyl)borane [B(C 6F5)3] at ambient temperature under solvent-free condition. Major advantages of this method include high yield, short reaction time, simple procedure, compatibility with sensitive protecting groups as well as other functional groups, absence of racemization of optical active compounds, and epimerization of sugars.
- Prajapti, Santosh Kumar,Nagarsenkar, Atulya,Babu, Bathini Nagendra
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p. 1784 - 1787
(2014/03/21)
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- Solventless acetylation of alcohols and phenols catalyzed by supported iron oxide nanoparticles
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Supported iron oxide nanoparticles on silicate catalysts were found to be efficient and easily recoverable materials in the acetylation of alcohols and phenols to their corresponding acetyl compounds using acetic anhydride under mild and solvent-less conditions. The supported iron oxide nanoparticles could be easily recovered from the reaction mixture and reused ten times without any loss in activity.
- Rajabi, Fatemeh,Luque, Rafael
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p. 129 - 132
(2014/01/06)
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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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- 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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- 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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p. 1624 - 1638
(2012/05/04)
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- Fluorogenic detection of hydrogen sulfide via reductive unmasking of o-azidomethylbenzoyl-coumarin conjugate
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Selective detection of hydrogen sulfide was achieved with 7-o-2′-(azidomethyl)benzoyl-4-methylcoumarin via analyte mediated reductive removal of the 2′-(azidomethyl)benzoyl moiety and concurrent generation of fluorescent 7-hydroxy-4-methylcoumarin. This journal is The Royal Society of Chemistry 2012.
- Wu, Zhisheng,Li, Zhu,Yang, Liu,Han, Jiahuai,Han, Shoufa
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supporting information
p. 10120 - 10122
(2012/11/13)
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- Lipase catalysed substituted coumarins with antioxidant activity
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Lipase has been employed as a green catalyst to esterify 7- and 6-hydroxy-4-methyl-coumarin with different fatty and acetic acid. The esterified coumarins have been evaluated for antioxidant activities using DPPH and ABTS assays, among them 3a and 5a are known as active antioxidants.
- Kidwai, Mazaahir,Poddar, Vaishali,Poddar, Roona
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experimental part
p. 715 - 720
(2011/07/08)
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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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scheme or table
p. 4363 - 4373
(2010/09/12)
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- Enzyme catalyzed acylation of 7-hydroxy-4methyl-2 H-chromenc-2-one using microwave
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Acylation of pharmacologically important 7-hydroxy-4mcihyl-2 H-chromcnc-2-onc has been investigated in the presence of immobilized lipase under the influence of microwave. Commercially available lipase (Novozyme 435) under microwave leads to enhancement in rate of reaction in comparison with conventional heating in immobilized lipase catalyzed acylation with various acids. Different microwave assisted technologies were studied and compared. This paper investigates the synergism between enzyme catalysis and microwaves on acylation of 7hydroxy-4-mcthyl-2 H-chromcnc-2-onc, with different acids using lipase Novozyme 435.
- Kidwai, Mazaahir,Mothsra, Poonam,Poddar, Roona
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experimental part
p. 1307 - 1310
(2010/02/28)
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- A heterogeneous cobalt(II) Salen complex as an efficient and reusable catalyst for acetylation of alcohols and phenols
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Acetylation of various alcohols and phenols was performed successfully using an immobilized cobalt(II) catalyst in high yield. The catalyst shows high thermal stability and was also recovered and reused at least 10 times without any considerable loss of activity.
- Rajabi, Fatemeh
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scheme or table
p. 395 - 397
(2009/05/07)
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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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- COUMARIN COMPOUNDS FOR THE TREATMENT OF CARDIOVASCULAR DISEASES AND PROCESS FOR PREPARING THE SAME
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The present invention relates to compounds of Formula (I): wherein- X and Y represent O, S, NR'; Rn represents alkyl, aryl, OR1, NH2, SR1, NR1R2. wherein R1, R2 = H, alkyl, phenyl, aryl, OCOR3, SCOR3, NHCOR3, NR1COR3, etc. (wherein R3 represents alkyl, phenyl, aryl, heteroaryl); R' and R" represent H, alkyl, phenyl, substituted phenyl, phenyloxy, substituted phenyloxy, amino, monosubstitutedamino, disubstitutedamino, aryl, heteroaryl, aryloxy, heteroaryloxy, alkoxy, thioalkyl, thioalkyloxy, halo and a process for preparing the same.
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Page/Page column 9; 10
(2010/01/30)
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- Structure activity studies with xenobiotic substrates using carboxylesterases isolated from Arabidopsis thaliana
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Carboxylesterases (CXEs) catalyse the hydrolysis of xenobiotics and natural products radically altering their biological activities. Whereas the substrate selectivity of animal CXEs, such as porcine liver esterase (PLE) have been well studied, the respective enzymes in plants have yet to be defined and their activities determined. Using Arabidopsis thaliana (At) as a source, five representative members of the α/β hydrolase AtCXE family of proteins have been cloned, expressed and the purified recombinant proteins assayed for esterase activity with xenobiotic substrates. Two members, AtCXE5 and AtCXE18 were found to be active carboxylesterases, though AtCXE5 proved to be highly unstable as a soluble protein. AtCXE18 and the previously characterised S-formylglutathione hydrolase from Arabidopsis (AtSFGH) were assayed against a series of esters based on methylumbelliferone in which the acyl moiety was varied with respect to size and conformation. The same series was used to assay crude esterase preparation from Arabidopsis plants and the results compared with those obtained with the commonly used PLE. With straight chain esters, AtCXE18 behaved like PLE, but the Arabidopsis hydrolases proved less tolerant of branched chain acyl components than the mammalian enzyme. While none of the enzyme preparations accurately reflected all the activities determined with crude Arabidopsis protein extracts, the plant enzymes proved more useful than PLE in predicting the hydrolysis of the more sterically constrained esters.
- Cummins, Ian,Landrum, Marie,Steel, Patrick G.,Edwards, Robert
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p. 811 - 818
(2008/03/13)
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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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- An efficient ZrCl4 catalyzed one-pot solvent free protocol for the synthesis of 4-substituted coumarins
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A versatile and efficient route to 4-substituted coumarins via a Pechmann reaction using ZrCl4 as the catalyst (10 mol %) is described. This method provides several advantages over alternative procedures such as mild, solvent-free conditions at ambient temperature, and direct isolation of the products in high yields.
- Sharma,Janardhan Reddy,Sree Lakshmi,Radha Krishna
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p. 6119 - 6121
(2007/10/03)
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- Novel thiocoumarins as inhibitors of TNF-α induced ICAM-1 expression on human umbilical vein endothelial cells (HUVECs) and microsomal lipid peroxidation
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Different coumarin/thiocoumarin derivatives, that is, 7-hydroxy-4- methylcoumarin, 7,8-dihydroxy-4-methylcoumarin, 7-acetoxy-4-methylcoumarin, 7,8-diacetoxy-4-methylcoumarin, 7-hydroxy-4-methylthiocoumarin, 7,8-dihydroxy-4-methylthiocoumarin, 7-acetoxy-4-methylthiocoumarin and 7,8-diacetoxy-4-methylthiocoumarin were synthesized and evaluated for their effects on TNF-α induced expression of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells and on NADPH-catalyzed rat liver microsomal lipid peroxidation with a view to identify modulators for expression of cell adhesion molecules and to establish structure-activity relationship. We found that dihydroxy and diacetoxy derivatives of thiocoumarin were more potent in comparison to the corresponding coumarin derivatives in inhibiting TNF-α-induced expression of ICAM-1. However, coumarin derivatives were found to be more potent in comparison to the corresponding thiocoumarins in inhibiting microsomal lipid peroxidation. We have also tested the intermediate compounds 7,8-dibenzyloxy-4-methylcoumarin and 7,8-dibenzyloxy-4- methylthiocoumarin for their inhibitory activity on TNF-α-induced ICMA-1 expression. We found that dibenzyloxy-4-methylthiocoumarin is better than dibenzyloxy-4-methylcoumarin. The mechanisms underlying the observed activities of coumarins and thiocoumarins have been discussed with reference to their structures. Such structure-function relationship studies may help in developing molecules with better anti-inflammatory and anti-oxidant activities.
- Kumar, Sarvesh,Singh, Brajendra K.,Kalra, Neerja,Kumar, Vineet,Kumar, Ajit,Prasad, Ashok K.,Raj, Hanumantharao G.,Parmar, Virinder S.,Ghosh, Balaram
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p. 1605 - 1613
(2007/10/03)
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- Synthesis of novel amino and acetyl amino-4-methylcoumarins and evaluation of their antioxidant activity
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The six novel 4-methylcoumarins bearing different functionalities such as amino, hydroxy, N-acetyl, acetoxy and nitro have been synthesized and confirmed on the basis of their spectral data (1H-, 13C-NMR, UV, IR and EI mass). They were examined for the first time for their effect on NADPH dependent liver microsomal lipid peroxidation in vitro, and the results were compared with other model 4-methylcoumarin derivatives to establish the structure-activity relationship. Our studies demonstrated that amino group is an effective substitute for the hydroxyl group for antioxidant property and produced a dramatic inhibition of lipid peroxidation. Ortho dihydroxy and ortho hydroxy-amino coumarins were found to possess highest antioxidant and radical scavenging activities.
- Tyagi, Yogesh K.,Kumar, Ajit,Raj, Hanumantharao G.,Vohra, Parag,Gupta, Garima,Kumari, Ranju,Kumar, Pankaj,Gupta, Rajinder K.
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p. 413 - 420
(2007/10/03)
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- A cheap, simple, and versatile method for acetylation of alcohols and phenols and selective deprotection of aromatic acetates under solvent-free condition
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Acyclic and cyclic acetates of various alcohols and phenols were obtained in excellent yields under mild reaction conditions in the presence of a catalytic amount of sodium hydroxide under solvent-free conditions and microwave irradiation. Selective deprotection of acetate group from the corresponding phenolic compounds was carried out in the presence of LiClO4· 2H2O. Copyright Taylor & Francis, Inc.
- Rajabi, Fatemeh,Saidi, Mohammad R.
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p. 483 - 491
(2007/10/03)
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- Psoralens for pathogen inactivation
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Psoralen compound compositions are synthesized which have primaryamino substitutions on the 3-, 4-, 5-, and 8- positions of the psoralen, which yet permit their binding to nucleic acid of pathogens. Reaction conditions that photoactivate these psoralens result in the inactivation of pathogens which contain nucleic acid. The compounds show similar activity in test systems to 4'' and 5'' derivatives of psoralen useful for inactivation of pathogens in blood products. In addition to the psoralen compositions, the invention contemplates such inactivating methods using the new psoralens.
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- New routes for the synthesis of some hydroxy 2H-1-benzopyran-2-thione derivatives
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The title compounds hydroxy 2H-1-benzopyran-2-thiones, (3a-e, 5a-f) have been synthesised from acetoxythiones by AlCl3 catalysed hydrolysis of -OCOCH3 group and in the second case by using the Lawesson's reagent for thionation of various hydroxycoumarin derivatives.
- Gadre,Audi,Karambelkar
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- New Phenolic Components from Dalbergia Volubilis
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Phytochemical examination of non green branches of Dalbergia volubilis on extensive column and preparative thin layer chromatography yielded twelve compounds eight of which are already known compounds and were identified as sitosterol, 7-hydroxy-4-methyl-coumarin, dalbergin, biochanin-A, umbelliferone, p-hydroxy cinnamic acid, kaempferol and quercetin-3-O-glucoside.The other four compounds were new natural products, three of which were identified as novel 4-phenyl-2H-1-benzopyran-2-ones while the fourth one was a new 12a-hydroxy rotenoid.The structure of these new compounds has been established on the basis of chemical and spectral evidences and through derivatization, as 4',7-dihydroxy-3'-methoxy-4-phenyl-2H-1-benzopyran-2-one, 3',7-dihydroxy-4',5-dimethoxy-2H-1-benzopyran-2-one, 3',7-dihydroxy4',5-dimethoxy-6-formyl-2H-1-benzopyran-2-one and a complex rotenoid determined to be as (VII).The co-occurence of 4-methyl-2H-1-benzopyran-2-ones, 4-phenyl-2H-1-benzopyran-2-ones, isoflavones and rotenoids is of interest from biogenetic considerations.
- Chawla, H. Mohindra,Johny, C. J.,Mittal, Ram S.
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- 13C Nuclear Magnetic Resonance Spectroscopy of 4-Methylcoumarins (4- Methyl-2H-1-benzopyran-2-ones)
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The 13C NMR spectra of 36 differently substituted 4-methylcoumarins (4-methyl-2H-1-benzopyran-2-ones) have been recorded.The effects of an alkyl side-chain at C-3 on the chemical shift values and that of a methoxy or an acetoxy group in place of a hydroxy group have been observed and rationalized.This study may be helpful in the structure elucidation of nei and natural 4-methylcoumarins. KEY WORDS 13C NMR chemical shifts 4-Methylcoumarins 4-Methyl-2H-1-benzopyran-2-ones.
- Parmar, V. S.,Singh, S.,Boll, P. M.
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p. 430 - 433
(2007/10/02)
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- Studies on Stable Diazoalkanes as Potential Fluorogenic Reagents. I. 7-Substituted 4-Diazomethylcoumarins
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As a new type of stable diazoalkane, 4-diazomethylcoumarins (4) bearing various 7-substituents were prepared for potential use in introducing fluorophores into acidic substances.Selenium dioxide oxidation of 4-methylcoumarins to the corresponding coumarin-4-carbaldehydes followed by triethylamine-mediated Bamford-Stevens reaction of their tosylhydrazones readily gave 4 as excellently stable and almost non-fluorescent crystals, exhibiting characteristic diazomethyl 1H- and 13C-nuclear magnetic resonance signals.Labeling reactions of carboxylic acids using 4 in refluxing chloroform in the presence of silica gel catalyst gave excellent yields of fluorescent coumarin-4-ylmethyl esters.In view of their stability, accessibility and fluorogenicity, these compounds (4), especially those bearing 7-methoxy and 7-acetyloxy substituents, should be practically useful fluorogenic reagents for carboxylic acids.Keywords - stable diazoalkane; 4-diazomethylcoumarin; selenium dioxide oxidation; Bamford-Stevens reaction; diazomethyl NMR; silica gel-catalyzed reaction; fluorescent esterification of carboxylic acid; coumarin-4-ylmethyl ester fluorescence
- Ito, Keiichi,Maruyama, Junko
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p. 3014 - 3023
(2007/10/02)
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