نتایج جستجو برای: keto enol tautomerism

تعداد نتایج: 7535  

2010
Madhukar Hemamalini Hoong-Kun Fun

The mol-ecular structure of the title compound, C(8)H(12)N(2)O, indicates that 2-isopropyl-6-methyl-pyrimidin-4-ol (the enol-form) undergoes an enol-to-keto tautomerism during the crystallization process. The pyrimidin-4(3H)-one group is essentially planar, with a maximum deviation of 0.081 (1) Å for the O atom. In the crystal structure, symmetry-related mol-ecules are linked into centrosymmeti...

Journal: :The journal of physical chemistry. B 2015
Avisek Ghose Mateusz Rebarz Oleg V Maltsev Lukas Hintermann Cyril Ruckebusch Eduard Fron Johan Hofkens Yves Mély Panče Naumov Michel Sliwa Pascal Didier

The first systematic steady-state and time-resolved emission study of firefly oxyluciferin (emitter in firefly bioluminescence) and its analogues in aqueous buffers provided the individual emission spectra of all chemical forms of the emitter and the excited-state equilibrium constants in strongly polar environment with strong hydrogen bonding potential. The results confirmed the earlier hypoth...

2009
Kentaro Takano Masayuki Takahashi Takaaki Fukushima Takashi Shibahara

The mol-ecule of the title compound, C(21)H(16)N(2)O, exists in the keto form and the C=O and N-H bonds are mutually cis in the crystal structure, although an enol form would be possible through tautomerism. The dihedral angle between the quinoline and the naphthalene systems is 22.04 (2)°. A bifurcated intramolecular N-H⋯(O,N) hydrogen bond is present.

Journal: :journal of physical & theoretical chemistry 2011
m. falahati m. monajjemi

single walled nanotubes (swnt) are common interested nanovehicle to make biosensors more sensitive.carbon nanotubes (cnts) have many distinct properties make them to be exploited to develop the nextgeneration of such nano sensors .the keto-enol tautomerization is one of the most common investigatedsubjects of isomerism in this regards, sensors are devices that are able to detect and change the ...

Journal: :The Journal of antibiotics 1996
R Uchida K Shiomi J Inokoshi H Tanaka Y Iwai S Omura

androstane skeleton with a keto-enol tautomerism at the cyclopentane ring. Wecarried out further isolation for PFTase inhibitors from the cultured broth of strain FO-3929 and found andrastin D (4, Fig. 1). In this paper, fermentation, isolation, structure elucidation, and biological properties of 4 are described. A stock culture of strain FO-3929 was inoculated into six 500-ml Erlenmeyer flasks...

Journal: :Organic & biomolecular chemistry 2012
Arepalli Sateesh Kumar P V Amulya Rao Rajagopal Nagarajan

Biologically and pharmaceutically active core structures containing a new class of 4-hydroxy-α-carbolines, dihydropyrido[2,3-b]indoles, pyrimido[4,5-b] and [5,4-b]indoles have been synthesized in good yields via Pd-catalyzed amidation and cyclizations. The keto-enol tautomerism in 4-hydroxy-α-carbolines has been investigated by DFT calculations and spectroscopic techniques. The fluorescence stu...

2013

In this laboratory exercise we will measure the Equilibrium Constant Kc for the keto-enol tautomerism of two -diketones and two -diketoesters. This will be accomplished by measuring the signal strength of key protons in the Nuclear Magnetic Resonance (NMR) spectrum of the equilibrium system. The influence of the solvent on the equilibrium position will be examined by considering the measured ...

2015
B. ESMAEILI A. MORSALI

The Acamprosate is a significant drug for alcohol abuse therapy, which may be an effective treatment for tinnitus, too. The Acamprosate has two possible tautomers, Keto and Enol tautomers. Each of the tautomers involves two important conformers. In this work, employing density functional theory (DFT) and handling the solvent effects with the PCM model, the structural parameters, energetic behav...

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