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关键词:'pyrans'
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Studies on the biosynthesis of cholesterol. 5. Biosynthesis of squalene from DL-3-hydroxy-3-methyl [2-14C] pentano-5-lactone.
J W CORNFORTH et al.
The Biochemical journal, 69(1), 146-155 (1958-05-01)
Rafat M Mohareb et al.
Steroids, 84, 46-56 (2014-04-02)
The one pot reaction of estrone with the aromatic aldehydes 2a-c and either of malononitrile or ethyl cyanoacetate afforded the fused pyran derivatives 4a-f. On the other hand, carrying the same reaction using thiourea instead of the cyanomethylene reagent gave
zeta-Collidine as a basis for buffering fixatives.
H S BENNETT et al.
The Journal of biophysical and biochemical cytology, 6(1), 113-114 (1959-08-01)
Rafat M Mohareb et al.
Steroids, 98, 80-91 (2015-03-12)
The reaction of androstenedione with bromine gave the 16-bromo derivative 2. The latter reacted with either cyanothioacetamide or thiourea to give the 2-cyanomethylthiazole derivative 4 and the 2-aminothiazole derivative 13. Compound 4 and 13 were used underwent some condensation, coupling
Rafat M Mohareb et al.
Steroids, 86, 45-55 (2014-05-06)
The reaction of androstenedione with either malononitrile or ethyl cyanoacetate and aromatic aldehydes 2a-c gave the pyran derivatives 4a-f, respectively. On the other hand, the reaction of androstenedione with thiourea and the aromatic aldehydes 2a-c gave the pyrimidine derivatives 6a-c
ANTI-INFLAMMATORY ACTIVITY ON NONSTEROIDAL AGENTS IN A RAT GRANULOMA ASSAY.
R I DORFMAN et al.
Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.), 119, 859-862 (1965-07-01)
Rafat M Mohareb et al.
Molecules (Basel, Switzerland), 20(6), 11535-11553 (2015-06-26)
In this work, 3-bromoacetylcoumarin was used as the key starting material for the synthesis of pyran, pyridine, thiophene, thiazole and pyrazole derivatives through its reaction with different reagents. The structures of the newly synthesized compounds were confirmed on the basis
M M V Ramana et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 152, 165-171 (2015-07-25)
In the present work, isopropyl-6-amino-4-(3,5-bis(trifluoromethyl)phenyl)-5-cyano-2-methyl-4H-pyran-3-carboxylate (4H-pyran analog) has been synthesized by a three component reaction catalyzed by CsOH/γ-Al2O3 and characterized. The interaction of 4H-pyran analog with herring sperm DNA (hs DNA) under physiological conditions (phosphate buffer of pH 7.2) was
Santhosh Reddy Mandha et al.
The Journal of organic chemistry, 77(23), 10648-10654 (2012-11-08)
Oxidative difunctionalization of 2-amino-4H-pyrans was accomplished with iodobenzene diacetate (IBD) and N-chlorosuccinimide (NCS) reagents in alcoholic medium. 2-Amino-4H-pyrans undergo geminal dialkoxylation with the migration of an amino group (1a,b, 2a-i, 3a,b, and 4) in IBD, whereas with NCS addition of
Ahmad Shaabani et al.
Chemical & pharmaceutical bulletin, 58(2), 270-272 (2010-02-02)
Pyridine-functionalized MCM-41 catalyzed reactions between tetracyanoethylene and various activated CH-acid compounds are described. These reactions afford the corresponding pyran annulated heterocyclic ring systems in high yields at room temperature within a few minutes. The work-up procedure is very simple and
Mukund P Sibi et al.
Journal of the American Chemical Society, 128(41), 13346-13347 (2006-10-13)
This paper describes a highly site-, diastereo-, and enantioselective intermolecular radical addition/hydrogen atom transfer to hydroxypyrone pyromeconic and kojic acids. The methodology can be extended to the formation of chiral quaternary centers. The products obtained are densely functionalized pyran moieties.
Tamer S Saleh et al.
Ultrasonics sonochemistry, 19(3), 491-497 (2011-11-29)
Novel fused pyrans were synthesized from the reaction of the tetrahydropyran-4-one with arylidine malononitriles. Different fused pyran derivatives were obtained from the mentioned reaction depending on type of catalyst used and type of energy used. Reactions were carried out under
Andrew Morrell et al.
Bioorganic & medicinal chemistry letters, 16(7), 1846-1849 (2006-01-31)
A method has been developed that relies on a two-step, one-pot condensation between phthalide and 2-carboxybenzaldehydes to provide benz[d]indeno[1,2-b]pyran-5,11-diones in a multi-gram fashion. Treatment of these compounds with a primary amine allows rapid access to various N-substituted indenoisoquinolines, whose in
Issa Yavari et al.
Molecular diversity, 10(2), 265-270 (2006-06-17)
Protonation of the reactive intermediates produced in the reaction between alkyl(aryl) isocyanides and dialkyl acetylenedicarboxylates by indan-1,3-dione leads to vinylnitrilium cations, which undergo carbon centered Michael type addition with the conjugate base of the CH-acid to produce functionalized 5-oxo-4,5-dihydroindeno[1,2-b]pyrans.
Gadepalli Narasimha Krishna Kumari et al.
Zeitschrift fur Naturforschung. C, Journal of biosciences, 59(5-6), 405-407 (2008-11-13)
The microbial transformation of coumarin (1) and 6-methyl coumarin (2) using Colletotrichum capsici gave 2-(3'-hydroxypropyl) phenol (3) and 2-(3'-hydroxypropyl)-4-methyl phenol (4). The phytopathogenic fungi effectively reduced the 2H-pyran-2-one moiety of both parent coumarins to respective alcohols.
Jing Sun et al.
ACS combinatorial science, 13(4), 421-426 (2011-05-17)
A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the
A novel and efficient one-pot four-component tandem approach for the synthesis of pyran derivatives.
Zhanyi Zhang et al.
Molecular diversity, 16(3), 423-430 (2012-06-26)
A series of new pyran derivatives are efficiently synthesized in a one-pot four-component tandem reaction via Suzuki coupling followed by a three-component reaction from readily available 4-bromobenzaldehyde, activated methylene compounds, and carbonyl compounds. Single crystal X-ray structure of the synthesized
Eduardo A Solano Espinoza et al.
Journal of mass spectrometry : JMS, 44(10), 1452-1458 (2009-09-02)
The potential energy profiles for the mutual conversion of the isomeric molecular ions [C5H6O]+* of 2-methylfuran, 3-methylfuran and 4H-pyran and the fragmentations that lead to [C(5)H(5)O](+) ions were obtained from calculations at the B3LYP/6-311G++(3df,3pd)//B3LYP/6-31G(d,p) level of theory. The various competing
Hamid Reza Safaei et al.
Molecular diversity, 16(4), 669-683 (2012-09-13)
CaCl(2) is applied as an efficient reusable and eco-friendly bifunctional catalyst for the one-pot three-component synthesis of 4H-pyrans under ultrasonic irradiation. A broad range of substrates including the aromatic and heteroaromatic aldehydes, indoline-2,3-dione (isatin) derivatives, acenaphthylene-1,2-dione (acenaphthenequinone) and 2, 2-dihydroxy-2H-indene-1,3-dione
Dalip Kumar et al.
European journal of medicinal chemistry, 44(9), 3805-3809 (2009-05-08)
A facile one-pot expeditious synthesis of 2-amino-4H-pyrans and 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes has been described under solvent-free conditions using magnesium oxide as a catalyst in very good yields. The reaction catalyst, magnesium oxide was reused and recycled without any loss of activity and
Joon-Bae Lee et al.
Molecules (Basel, Switzerland), 25(1) (2019-12-28)
Methanol is metabolized in the body to highly toxic formaldehyde and formate when consumed accidentally. Methanol has been typically analyzed with gas chromatography-flame ionization detector (GC-FID). However, its retention time may overlap with other volatile compounds and lead to confusion.
Penchal Reddy Nandaluru et al.
Organic letters, 14(1), 310-313 (2011-12-17)
A multicomponent domino reaction that affords 6H-dibenzo[b,d]pyran-6-ones is reported. The overall transformation consists of six reactions: Knoevenagel condensation, transesterification, enamine formation, an inverse electron demand Diels-Alder (IEDDA) reaction, 1,2-elimination, and transfer hydrogenation. Both the diene and dienophile for the key
Lei Dong et al.
Chemistry (Weinheim an der Bergstrasse, Germany), 26(63), 14445-14452 (2020-08-31)
Two red-emitting dicyanomethylene-4H-pyran (DM) based fluorescent probes were designed and used for peroxynitrite (ONOO- ) detection. Nevertheless, the aggregation-caused quenching effect diminished the fluorescence and restricted their further applications. To overcome this problem, tetraphenylethylene (TPE) based glycoclusters were used to
Gary E Keck et al.
Journal of the American Chemical Society, 133(4), 744-747 (2010-12-24)
Bryostatin 1 is a marine natural product that is a very promising lead compound because of the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The
Rafat Milad Mohareb et al.
Chemical & pharmaceutical bulletin, 63(9), 678-687 (2015-09-04)
A series of coumarin analogues bearing 4H-pyran rings 2a-d, 11a-d and 1,4-dihydropyridine rings 3a-d, 12a-d at position 3 were synthesized starting from either 3-acetyl coumarin (1) or the coumarin acetohydrazide derivative 4. Condensation of 3-acetylcoumarin (1) with 2-cyanoacetohydrazide afforded 2-cyano-N'-{1-[2-oxo-2H-chromen-3-yl]ethylidene}acetohydrazide
J Marco-Contelles et al.
Carbohydrate research, 335(1), 63-70 (2001-09-13)
The reaction of DIBALH with bis(heteroannulated)-pyranosides containing the perhydrofuro[2,3-b]pyran moiety is described. The hydride attack at the anomeric carbon (C-9a) resulted in the exclusive tetrahydrofuran ring opening. The selectivity of this reaction has been evaluated as other benzylidene acetals built
Eun-Mi Lee et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 92, 33-36 (2012-03-10)
Temperature and pH responsive poly(N-isopropylacrylamide) (poly(NIPAM)) copolymer containing D-π-A type pyran-based fluorescent dye (fluorophore) and basic comonomer, N-[3-(dimethylamino)propyl]-methacrylamide (DMAPAM) was prepared by free radical polymerization. With increase of pH values, aqueous poly(NIPAM-co-DMAPAM-co-fluorophore) solution showed decrease of a lower critical solution
E Abdel-Sattar
Archives of pharmacal research, 21(6), 785-786 (1998-12-30)
The aerial parts of Teucrium yemense yielded two iridoid glycosides. Their structures were elucidated by spectral means as teucardosid and 8-O-acetylharpagid.
Yang Li et al.
Carbohydrate research, 344(16), 2270-2273 (2009-09-19)
X-ray diffraction analyses of iridoid glycoside aucubin (1) and its aglycone aucubigenin (2) are reported. It was found that crystals of 1 are orthorhombic, with P2(1)2(1)2(1) space group, both cyclopentane ring and pyran ring adopt envelope conformations, and the Glc
M M Santos et al.
World journal of microbiology & biotechnology, 28(6), 2435-2440 (2012-07-19)
The aim of this work is to study the conversion of oleuropein-a polyphenol present in olives and olive oil by-products-into hydroxytyrosol, a polyphenol with antioxidant and antibacterial properties. The hydrolysis reaction is performed by lactic acid bacteria. Six bacterial strains
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