排序方式: 共有15条查询结果,搜索用时 16 毫秒
1.
Varamesh Amir Prathapan Ragesh Telmadarreie Ali Li Jia Gourlay Keith Minhas Gurminder Lu Qingye Bryant Steven L. Hu Jinguang 《Cellulose (London, England)》2022,29(2):985-1001
Cellulose - There has been significant interest over recent years in the production and application of sustainable and green materials. Among these, nanocellulose has incurred great interest... 相似文献
2.
Prathapan A Lijo Cherian O Nampoothiri SV Mini S Raghu KG 《Natural product research》2011,25(3):298-309
Saraca ashoka is a widely used medicinal herb claimed to cure many diseases. This study investigated the antiperoxidative, free radical scavenging and xanthine oxidase (XO) inhibitory potential of the ethyl acetate fraction of S. ashoka flowers (SAF) and compared it with standard compounds like gallic acid, ascorbic acid, butylated hydroxyl toluene and allopurinol. The ethyl acetate fraction of SAF exhibited free radical scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl radical and superoxide radical, along with hydroxyl radical scavenging activity. Lipid peroxidation inhibitory potential of SAF was studied using a linoleic acid emulsion system, which shows significant antioxidant potential. SAF also demonstrated significant XO (key enzyme linked to inflammation) inhibitory activity, which revealed its therapeutic potential as an antioxidant and XO inhibitor. HPLC profiling of the ethyl acetate fraction of SAF revealed that it contains ellagic acid as a major compound and thus the beneficial effects of this fraction may be due to the presence of this compound. 相似文献
3.
Nampoothiri SV Binil Raj SS Prathapan A Abhilash PA Arumughan C Sundaresan A 《Natural product research》2011,25(3):277-287
Terminalia bellerica has been used as a traditional medicine in a variety of ailments including anaemia, asthma, cancer, inflammation, rheumatism and hypertension. In this study, the free radical scavenging and antioxidant activities of methanol extract (ME) and its different solvent fractions (namely hexane (HE), ethyl acetate (EA), butanol (BL) and water (WA)) of the T. bellerica fruit pericarp were evaluated and compared with standard antioxidant compounds like gallic acid (GA), catechin and ascorbic acid. Among the different fractions tested, the EA fraction exhibited higher antioxidant and radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide and hydroxyl radicals than the other fractions, which may be attributed to its higher phenolic and flavonoid content, since a linear relation was observed between the phenolic content and the antioxidant parameters. The HPTLC analysis of the EA fraction revealed that it mainly contains GA and ferulic acid (FA) as major phenolics, and the higher antioxidant activities of EA fraction may be due to the presence of these compounds. 相似文献
4.
Solvent effects in the reaction between (anthracen‐9‐yl)methyl sulfides and electron‐deficient acetylenes 下载免费PDF全文
Reshma Gopalakrishnan Jomon P. Jacob Rekha R. Mallia Perupparampil A. Unnikrishnan Sreedharan Prathapan 《Journal of Physical Organic Chemistry》2015,28(7):472-479
Solvent‐dependent diverse reactivity of (anthracen‐9‐yl)methyl sulfides with a few electron‐deficient acetylenes is described. Diversity in reactivity is attributed to competition between one electron transfer, two electron transfer and Diels–Alder reaction of these sulfides with electron‐deficient acetylenes. We have proposed plausible mechanisms to account for various reactions observed by us. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
5.
Jomon P. Jacob Reshma Gopalakrishnan Rekha R. Mallia Jean John Vadakkan Perupparampil A. Unnikrishnan Sreedharan Prathapan 《Journal of Physical Organic Chemistry》2014,27(11):884-891
Herein, we describe diverse reactivity of (anthracen‐9‐yl)methanamines with a few electron‐deficient acetylenes. Depending on the solvent and concentration, (anthracen‐9‐yl)methanamines reacted with acetylenes through one electron transfer, two electron transfer, or Diels–Alder pathways; and under certain conditions, we observed multiple reaction pathways. We have proposed plausible mechanisms to account for various reactions observed by us. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
6.
Jean J. Vadakkan Sreedharan Prathapan Perupparampil A. Unnikrishnan 《Tetrahedron letters》2005,46(35):5919-5922
(Anthracen-9-yl)methanamines were found to undergo single electron-transfer mediated C-N bond cleavage in the presence of excess dimethyl acetylenedicarboxylate (DMAD) in non-polar solvents leading to the formation of lepidopterene (4) and 1,2-bis(9-anthracenyl)ethane (3). The structure of lepidopterene was confirmed on the basis of NMR data and by X-ray crystallography. 相似文献
7.
The dehydration of aldoximes and amides, and oxidation of benzoin are accomplished in one-pot using in situ–generated Burgess-type reagent.
Keywords: Amide, benzil, benzoin, Burgess reagent, Burgess-type reagent, dehydration, nitrile, oxidation, oxime
8.
Hydrogen abstraction and fragmentation occur on acetone-sensitized photolysis of 4-alkylpyrimidines 1a-c with formation of 4-methylpyrimidine (2); the selectivity for primary, secondary, and tertiary hydrogen transfer is considerably greater in 1a-c than in 2-alkylquinolines 7a-c. 相似文献
9.
Miller MA Lammi RK Prathapan S Holten D Lindsey JS 《The Journal of organic chemistry》2000,65(20):6634-6649
We have prepared a linear array of chromophores consisting of a perylene input unit, a bis(free base porphyrin) transmission unit, and a free base phthalocyanine output unit for studies in artificial photosynthesis and molecular photonics. The synthesis involved four stages: (1) a rational synthesis of trans-AB2C-porphyrin building blocks each bearing one meso-unsubstituted position, (2) oxidative, meso,meso coupling of the zinc porphyrin monomers to afford a bis(zinc porphyrin) bearing one phthalonitrile group and one iodophenyl group, (3) preparation of a bis(porphyrin)-phthalocyanine array via a mixed cyclization involving the bis(free base porphyrin) and 4-tert-butylphthalonitrile, and (4) Pd-mediated coupling of an ethynylperylene to afford a perylene-bis(porphyrin)-phthalocyanine linear array. The perylene-bis(porphyrin)-phthalocyanine array absorbs strongly across the visible spectrum. Excitation at 490 nm, where the perylene absorbs preferentially, results in fluorescence almost exclusively from the phthalocyanine (phi(f) = 0.78). The excited phthalocyanine forms with time constants of 2 ps (90%) and 13 ps (10%). The observed time constants resemble those of corresponding phenylethyne-linked dyads, including a perylene-porphyrin (< or = 0.5 ps) and a porphyrin-phthalocyanine (1.1 ps (70%) and 8 ps (30%)). The perylene-bis(porphyrin)-phthalocyanine architecture exhibits efficient light-harvesting properties and rapid funneling of energy in a cascade from perylene to bis(porphyrin) to phthalocyanine. 相似文献
10.
Nampoothiri Suresh V. Raj S. S. Binil Ranjith A. Prathapan A. Sundaresan Aandikkannu 《平面色谱法杂志一现代薄层色谱法》2011,24(1):77-81
JPC – Journal of Planar Chromatography – Modern TLC - For the first time a simple, sensitive, rapid, precise and accurate HPTLC method has been established for quantification of... 相似文献