- Synthesis of 5-Fluorocytosine Using 2-Cyano-2-fluoroethenolate as a Key Intermediate
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There is an urgent demand for 5-fluorocytosine (5-FC) due to its activity against HIV-induced fungal infections as well as its use as a key intermediate in the synthesis of the clinically highly important anti-HIV drug emtricitabine (FTC). We report a simple, low-cost five steps synthesis of 5-FC starting from chloroacetamide. Overall yields up to 46 % were achieved and the route is devoid of any chromatographic purifications. The previously unknown key intermediate (Z)-2-cyano-2-fluoroethenolate is obtained through a Claisen-type condensation from fluoroacetonitrile. As the direct cyclization with urea only gave poor yields, 5-fluoro-2-methoxypyrimidin-4-amine, 5-fluoro-2-(methylsulfanyl)pyrimidin-4-amine and 5-fluoropyrimidine-2,4-diamine served as synthetic intermediates.
- Dietz, Jule-Philipp,Derstine, Brenden P.,Ferenc, Dorota,Crawford, Evan T.,Arduengo, Anthony J.,Gupton, B. Frank,McQuade, D. Tyler,Opatz, Till
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supporting information
p. 5519 - 5526
(2019/07/17)
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- Method for preparing fluoroacetamide for quantitative and qualitative determination of forensic science
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The invention discloses a method for preparing fluoroacetamide for quantitative and qualitative determination of the forensic science. The method comprises the following steps: (1) dissolving fluoracyl chloride in an organic solvent, and then adding the obtained solution into a reaction kettle; (2) pumping ammonia into the reaction kettle, and performing stirring for reaction; (3) performing filtering, flushing the filter cake with an organic solvent, and merging organic phases; and (4) washing the organic phases with a saturated salt solution, performing drying, performing reduced pressure distillation to remove the organic solvent and to obtain a white solid, and performing forced air drying to obtain fluoroacetamide. The method is high in productivity, the prepared fluoroacetamide is high in purity and can directly serve as a standard substance or a reference material for use, and the demand for toxicological analysis of the forensic science in the reality is met.
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Paragraph 0021-0028
(2017/09/13)
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- Method for preparing a fluorinated organic compound
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A method for preparing a fluorinated organic compound (II) from an organic compound (I) comprising at least one nucleofugal group Nu, and also a preparation of different specific organic compounds, in particular a fluoro-methylpyrazole compound. The method comprises: a reaction, in the presence of water, of the organic compound (I) and at least one salt providing at least one fluoride anion; and a replacement of at least one nucleofugal group Nu of the compound (I) with a fluorine atom, in order to obtain the fluorinated organic compound (II).
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Paragraph 0293-0294
(2014/06/11)
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- Reactions of Cyclic Peroxides with Aldehydes and Ketones catalysed by Trimethylsilyl Trifluoromethanesulphonate. An Efficient Synthesis of 1,2,4-Trioxanes
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Trimethylsilyl trifluoromethanesulphonate is found to be an efficient catalyst for the reaction of 1,4-endoperoxides and 1,2-dioxetanes with aldehydes and ketones to give 1,2,4-trioxanes in high yields.
- Jefford, Charles W.,Boukouvalas, John,Kohmoto, Shigeo
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p. 523 - 524
(2007/10/02)
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- The photochemical addition of N-haloamides to olefins: the influence of various factors on the competition between 1,2-addition and hydrogen abstraction
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In the photodecomposition of N-haloamides (ZCONRX) in the presence of olefins, the 1,2-addition chain competes with the hydrogen abstraction chain(s) leading to the parent amide (the quantum yields for these processes are greater than unity).The following factors were shown to have an influence on this competition as measured by the yield of 1,2-addition and the yield of parent amide in methylene chloride solutions: (i) the N-halogen (higher yields of addition with X=Cl than with X=Br); (ii) the electronegativity of Z (increase of the yield of addition as the electronegativity of Z increases); (iii) the temperature (higher yields of addition at lower temperatures, and at -70 degC, better yields of addition (>90percent, R=H) for X=Br than for X=Cl); and (iv) the size of R (dramatic decrease of the yield of 1,2-addition in going from R=H to R=CH3).Surprisingly, the presence of a scavenger for HX had no influence on the yield of 1,2-addition.Both the size and electronegativity of Z had an effect on the stereochemistry of 1,2-addition to cyclohexene.High yields of addition to a variety of olefins were obtained with N-chloroamides such as ClCH2CONHCl, C2H5OCONHCl, CF3CONHCl.Their addition to enol ethers at -70 degC led to the synthesis of α-amido acetals or ketals (aldehydes or ketones) and to an α-amido glycoside in good yields.
- Lessard, Jean,Mondon, Martine,Touchard, Daniel
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p. 431 - 450
(2007/10/02)
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