- A for the synthesis of anti-cancer auxiliary drug pyridine medical process for the preparation of intermediates
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The invention relates to the field of medical chemistry and discloses a method for synthesizing a pyridine medical intermediate, namely 2-bromo-3-chloro-5-trifluoromethyl pyridine, for synthesizing anti-cancer auxiliary medicines. The method comprises the following steps of: (1) reacting 6-hydroxynicotinic acid, hydrofluoric acid and sulfur tetrafluoride at the temperature of between 100 and 120DEG C and under the pressure of 0.1-0.3MPa, and adding water to obtain 2-hydroxy-5-trifluoromethyl pyridine; (2) reacting with N-chlorosuccinimide, and performing water precipitation to obtain 3-chloro-5-trifluoromethyl-2-hydroxypyridine; and (3) adding excessive phosphorus oxybromide, reacting at the temperature of between 145 and 160DEG C for 5 to 8 hours, cooling, violently stirring at the temperature of between -5 and 0DEG C, extracting, combining organic phases, drying, filtering, performing spin drying, and purifying by using a silica gel column. According to the method, raw materials are readily available, the cost is low, the method is suitable for industrial production and the yield exceeds 38 percent.
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Paragraph 0025
(2017/01/26)
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- SOME NEW 2-SUBSTITUTED 5-TRIFLUOROMETHYLPYRIDINES
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The preparation of the derivatives of 2-amino-, hydrazino-, hydroxy-, and mercapto-5-trifluoromethylpyridines via 2-chloro precursors is describes.Experimental and spectral data of the products together with those of the precursors are presented.
- Haga, Takahiro,Fujikawa, Kan-ichi,Koyanagi, Tohru,Nakajima, Toshio,Hayashi, Kouji
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p. 117 - 124
(2007/10/02)
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