696-04-8Relevant academic research and scientific papers
Ozone and ozone/vacuum-UV degradation of diethyl dithiocarbamate collector: Kinetics, mineralization, byproducts and pathways
Fu, Pingfeng,Ma, Yanhong,Yang, Huifen,Li, Gen,Lin, Xiaofeng
, p. 23579 - 23588 (2019/08/12)
The diethyl dithiocarbamate (DDC) collector, a precursor of toxic N-nitrosamines, is detected in flotation wastewaters usually at the ppm level. In this study, the O3 and O3/Vacuum-UV (O3/VUV) processes were compared to investigate the efficient removal of DDC with a low risk of N-nitrosamine formation. The results showed that 99.55% of DDC was removed at 20 min by O3/VUV, and the degradation rate constant was 3.99 times higher than that using O3-alone. The C, S and N mineralization extents of DDC using O3/VUV reached 36.36%, 62.69% and 79.76% at 90 min, respectively. O3/VUV achieved a much higher mineralization extent of DDC than O3-alone. After 90 min of degradation, O3/VUV achieved lower residual concentrations of CS2 and H2S, and released lower amounts of gaseous sulfur byproducts compared to O3-alone. The solid phase extraction and gas chromatography-mass spectrometry (SPE/GC-MS) analysis indicated that the main byproducts in O3/VUV degradation of DDC were amide compounds without the detection of N-nitrosamines. The avoidance of N-nitrosamine formation might be attributed to exposure of UV irradiation and enhanced formation of OH radicals in the O3/VUV system. The degradation pathways of DDC were proposed. This work indicated that O3/VUV was an efficient alternative treatment technique for the removal of DDC flotation collector with low risk of N-nitrosamine formation.
Transfer hydrogenation as a redox process in nucleotides
Achrainer, Florian,Emel'yanenko, Vladimir N.,Tantawy, Waled,Verevkin, Sergey P.,Zipse, Hendrik
, p. 10426 - 10429 (2015/04/14)
Using a combined theoretical and experimental strategy, the heats of hydrogenation of the nucleotide bases uracil, thymine, cytosine, adenine, and guanine have been determined. The most easily hydrogenated base is uracil, followed by thymine and cytosine. Comparison of these hydrogenation enthalpies with those of ketones and aldehydes derived from sugar models indicates the possibility of near-thermoneutral hydrogen transfer between uracil and the sugar phosphate backbone in oligonucleotides. (Figure Presented)
Mechanochemical preparation of hydantoins from amino esters: Application to the synthesis of the antiepileptic drug phenytoin
Konnert, Laure,Reneaud, Benjamin,De Figueiredo, Renata Marcia,Campagne, Jean-Marc,Lamaty, Frdric,Martinez, Jean,Colacino, Evelina
, p. 10132 - 10142 (2015/02/19)
The eco-friendly preparation of 5- and 5,5-disubstituted hydantoins from various amino ester hydrochlorides and potassium cyanate in a planetary ball-mill is described. The one-pot/two-step protocol consisted in the formation of ureido ester intermediates, followed by a base-catalyzed cyclization to hydantoins. This easy-handling mechanochemical methodology was applied to a large variety of α- and β-amino esters, in smooth conditions, leading to hydantoins in good yields and with no need of purification steps. As an example, the methodology was applied to the "green" synthesis of the antiepileptic drug Phenytoin, with no use of any harmful organic solvent.
PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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, (2010/03/02)
The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
DIHYDROURACIL COMPOUNDS AS ANTI-ICTOGENIC OR ANTI-EPILEPTOGENIC AGENTS
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Page 34, (2010/11/30)
Methods and compounds useful for the inhibition of convulsive disorders, including epilepsy, are disclosed. The methods and compounds of the invention inhibit or prevent or treat ictogenesis, epileptogenesis, or epileptogenesis-associated conditions. Methods for preparing the compounds of the invention are also described. Particularly preferred compounds of the invention include Formula 1 as described herein.
Hydroxyl radical-induced cross-linking of thymine and lysine: Identification of the primary structure and mechanism
Morimoto, Syota,Hatta, Hiroshi,Fujita, Shin-Ichi,Matsuyama, Tomochika,Ueno, Toru,Nishimoto, Sei-Ichi
, p. 865 - 870 (2007/10/03)
Hydroxyl radical-induced formation of a cross-link of thymine (Thy) and lysine (Lys) in the γ-radiolysis of N2O-saturated aqueous solution was studied. A Thy-Lys cross-link (I) of the formal structure that OH radical and 4-carbon-centered Lys radical added respectively to C(5) and C(6) positions of Thy was isolated by a preparative HPLC and identified by a FAB-HRMS. The primary cross-link I was dehydrated by treatment with HCl at 120°C to yield the secondary structure (II) possessing a C(5)-C(6) double bond in the Thy moiety: the latter structure II was reported previously (Dizdaroglu, M.; Gajewski, E. Cancer Res. 1989, 49, 3463-3467). A pulse radiolysis study with a redox titration method indicated that 4-carbon centered Lys radical intermediate was of neutral redox reactivity in contrast to reducing reactivity of 5-hydroxy-5,6-dihydrothymin-6-yl radical intermediate. The cross-link I could be formed by a conventional radical recombination mechanism, but not by an ionic recombination mechanism involving a redox reaction between the radical intermediates.
Photoinduced reduction of thymine and uracil derivatives by hypophosphite: Unusual high quantum yield of chromophore loss
Wang, Kongjiang,Chai, Zhifang
, p. 1543 - 1544 (2007/10/03)
The quantum yield of chromophore loss of thymine, uracil and their corresponding nucleosides and nucleoside-5′-monophosphates undergoing irradiation with 254 nm UV light was found to be sharply enhanced by hypophosphite; thymine and uracil were reduced by hypophosphite to give 5,6-dihydrothymine and 5,6-dihydrouracil respectively.
Reactions of Ni(II) and its complexes with free radicals derived from thymine
Chakrabarti, S.,Mandal, P. C.,Bhattacharyya, S. N.
, p. 307 - 312 (2007/10/02)
The effects of nickel(II) ions and its complexes on the products arising from the γ-radiolysis of thymine were studied.The decomposition of the pyrimidine base and formation of different radiolytic products indicate that nickel(II) ions or its complexes have little effect on the radiosensitivity of thymine.The transient hydroxyl adduct of thymine reacts with Ni(II) with the formation of a complex having a nickel-carbon bond.The rate constants for the reactions are of the order of 106 dm3mol-1s-1.Possible mechanisms for the formation of different products in the radiolysis of thymine in the presence of nickel(II) compounds are discussed.
