23945-44-0Relevant articles and documents
Preparation method of important intermediate (uracil-5-carboxylic acid) of medicine (avanafil)
-
Paragraph 0014-0020, (2018/09/08)
The invention discloses a preparation method of an important intermediate (uraciluracil-5-carboxylic acid) of a medicine (avanafil), and belongs to the technical field of drug synthesis. The preparation method is characterized in that the uraciluracil-5-carboxylic acid is prepared by adopting thymine as a starting material and using oxygen for further oxidation under the action of an active-carbon-loaded catalyst. The preparation method disclosed by the invention has the advantages of high yield, low cost, economic and environment-friendly effects and applicability to industrialization and thelike and is a synthesis method with industrial production value.
PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
-
, (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.
Photochemical deamination and demethylation of 5-methylcytosine
Privat, Eric,Sowers, Lawrence C.
, p. 745 - 750 (2007/10/03)
Cytosine methylation is believed to play a pivotal role in eucaryotic cellular development as well as in viral latency. We have been investigating chemical mechanisms for the perturbation of methylation patterns, including the effects of ultraviolet radiation. We observed that, upon exposure to UV light, 5-methylcytosine (5mC) was converted to thymine, cytosine, and a series of 5-substituted cytosine derivatives as analyzed by gas chromatography/mass spectrometry. Deamination of 5mC to thymine proceeds via formation of the intermediate photohydrate. Formation of 5-substituted cytosine derivatives results from oxidation of the 5-methyl group with initial formation of 5-(hydroxymethyl)cytosine (hmC). Upon exposure to UV light, hmC is converted to cytosine. The conversion of hmC to cytosine likely results from photohydration and elimination of formaldehyde. It is proposed that endogenous oxidation and hydrolysis could result in demethylation of 5mC residues in DNA. Whereas hydrolytic deamination of 5mC to thymine has been widely discussed, demethylation of 5mC has not as yet been described.