- Synthesis of 4-amino-5-fluoropyrimidines and 5-amino-4-fluoropyrazoles from a β-fluoroenolate salt
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A synthesis of fluorinated pyrimidines under mild conditions from amidine hydrochlorides and the recently described potassium 2-cyano-2-fluoroethenolate was developed. A broad substrate scope was tested and mostly excellent yields were obtained. The synthesis of fluorinated aminopyrazoles from the same fluorinated precursor could be demonstrated but proceeded with lower efficiency.
- Dietz, Jule-Philipp,Lucas, Tobias,Opatz, Till
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supporting information
p. 445 - 450
(2020/03/27)
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- Preparation method of 5- flucytosine
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The invention belongs to the technical field of chemical synthesis of medicines and relates to a preparation method of 5-flucytosine. The preparation method comprises the following steps: utilizing ethyl formate and methyl chloroformate to synthesize 2-chloro-3-oxo methyl propionate, then utilizing oxymethylisourea to close rings to obtain pyrimidine rings, utilizing potassium fluoride to substitute chlorine on the pyrimidine rings, utilizing phosphorus oxytrichloride to substitute hydroxyl groups on the pyrimidine rings, then adding ammonia water to lead chloride to be substituted with aminogroups, and hydrolyzing under an acid condition to obtain a product, namely the 5-flucytosine. The preparation method has the beneficial effects that the methyl chloroacetate is adopted for substituting methyl fluoroacetate to be used as a synthetic raw material of the 5-flucytosine, so that the use of highly-toxic chemicals such as the methyl fluoroacetate is avoided; simultaneously, since the price of the methyl chloroacetate is much lower than the price of the methyl fluoroacetate, the production cost can be saved; by utilization of the synthetic route provided by the invention, the higher-purity 5-flucytosine can be prepared without need of complex aftertreatment steps; simultaneously, the preparation method has higher overall yield and obvious industrial value and is worthy of being promoted and used on a large scale.
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- 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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p. 5519 - 5526
(2019/07/17)
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- Method for 5-fluorocytosine
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A disclosed method for 5-fluorocytosine comprises a reaction shown in the specification, and the method is characterized by comprising the following steps: dissolving a compound shown as a formula IV in an organic solvent, adding triethylamine, dropwise adding phosphorus oxychloride at 40-100 DEG C, after dropwise adding is finished, keeping warm and stirring for reaction for 2-10 h, so as to obtain a compound shown as a formula III; adding the formula III compound into an organic solution of ammonia, and stirring at 40-80 DEG C for reacting for 2-8 h, so as to obtain a compound shown as a formula II; and adding the formula II compound into a hydrogen chloride organic solution, and stirring at 40-80 DEG C for reacting for 3-15 h, so as to obtain a compound shown as a formula I. The method realizes low-cost high-yield large-scale preparation of high-purity 5-fluorocytosine, and possesses substantial industrial value.
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Paragraph 0038; 0039; 0040
(2016/11/17)
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