- Preparation method of N4-hydroxycytidine
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The invention discloses a preparation method of N4-hydroxycytidine capable of preventing and treating various virus infection including COVID-19. The preparation method comprises the following steps: taking cytosine and tetraacetyl ribose as initial raw materials, and carrying out hydroxyamination, condensation and hydrolysis reaction to prepare the N4-hydroxycytidine. The preparation method is easily available in raw materials, simple in process, economical, environment-friendly and suitable for industrial production.
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Paragraph 0018; 0041-0044
(2021/08/28)
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- Preparation method of 5 '-isobutyryl-N4-hydroxycytidine
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The invention discloses a preparation method of 5 '-isobutyryl-N4-hydroxycytidine which has the effect of preventing and treating infection of various viruses including COVID-19. The preparation method comprises the following steps: taking D-ribose and cytosine as initial raw materials, respectively carrying out acetone protection, acylation and hydroxyamination reaction, and carrying out condensation and hydrolysis reaction on the obtained compound to obtain the compound 5 '-isobutyryl-N4-hydroxy cytidine shown in the formula I. The preparation method has the advantages of easily available raw materials, simple process, economy and environmental protection, and is suitable for industrial production.
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Paragraph 0017; 0051-0054
(2021/08/21)
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- Synthesis of modified pyrimidine bases and positive impact of chemically reactive substituents on their in vitro antiproliferative activity
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The antiproliferative activity screening on human tumor cell lines of a series of modified uracil and cytosine bases as well as some corresponding acyclonucleosides, and comparison of structure-activity relationship revealed the importance of chemical rea
- Noll, Steffi,Kralj, Marijeta,Suman, Lidija,Stephan, Holger,Piantanida, Ivo
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body text
p. 1172 - 1179
(2009/09/30)
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- Deuterium Isotope Effects and the Bunnet w Factor in Elimination Reactions of 4-Alkoxyimino-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-one in Strong Acid Media
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Rate coefficients for the elimination of hydroxylamines from 4-alkoxyimino-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-ones (1a) show maxima at H0 values of -1.8 (for O-benzylhydroxylamine) and -0.8 (for hydroxylamine) in a variety of mineral acids.The hitherto unknown values of H0 for trifluoromethanesulphonic acid are reported and this acid also gives a rate maximum at -1.8 for the elimination of O-benzylhydroxylamine from (1a; R2 = Bz).Bunnett w values for these eliminations fall in the range 6.0-16.0 (dependent upon the acid) implying that water is involved as a proton transfer agent.In contrast, eliminations in formic acid show low and variable w values and formate ion is involved as the proton transfer agent which explains the lack of a rate maximum in this acid.Deuterium isotope effects reveal a highly stereoselective elimination and support the proposal of an E1cB (irreversible) mechanism.The inhibition of elimination by the 5-fluoro-substituent is probably due to destabilisation of the intermediate carbanion by the lone pair electrons on fluorine.
- Atkins, Paul J.,Palling, David J.,Poon, Nai L.,Hall, C. Dennis
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p. 1107 - 1112
(2007/10/02)
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- Elimination and Hydrolysis Reactions of 4-Alkoxyimino-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-ones and 4-Alkoxyimino-5-fluoro-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-ones in Strong Acid Media
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The rate of elimination of hydroxylamines from 4-alkoxyimino-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-ones (Ia) in a number of acids is shown to be maximal at a H0 value of -1.8, with the exception of trifluoroacetic acid for which a linear increase in rate constant is observed with increasing acid strength.The results are explained by a mechanism involving the doubly protonated form of the substrate.With 4-alkoxyimino-5-fluoro-5,6-dihydro-6-alkoxyaminopyrimidin-2(1H)-ones (Ib), acid-catalysed hydrolysis to form 5-fluoro-5,6-dihydro-6-alkoxyaminopyrimidine-2,4(1H,3H)-diones (V) occurs in preference to the elimination reaction which in this case is ca. 750 times slower than with (Ia).The rate differences for elimination are explained by differences in conformation between the two substrates (Ia and b).
- Palling, David J.,Schalke, Peter M.,Atkins, Paul J.,Hall, C. Dennis
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p. 113 - 120
(2007/10/02)
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