- A norfloxacin, ciprofloxacin and enrofloxacin preparation method
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The invention discloses a preparation method of norfloxacin, ciprofloxacin and enrofloxacin. The preparation method comprises the following steps: directly reacting 1-ethyl-6-fluoro-7-chlo-4-oxo-1,4-dihydro-quinoline-3-carboxylate or 1-cyclopropyl-6-fluoro-7-chlo-4-oxo-1,4-dihydro-quinoline-3-carboxylate with piperazine (or N-ethyl piperazine); and then, performing after-treatment to prepare a corresponding target product norfloxacin (or ciprofloxacin or enrofloxacin). The preparation method disclosed by the invention is short in reaction step, convenient to operate, less investment and beneficial to industrial production; consumption of piperazine (or N-ethyl piperazine) can be reduced by more than half; under the catalytic action, the reaction temperature is low, the byproducts are less, the yield is high and the cost is low; heavy use of inorganic acid and inorganic alkaline is avoided, so that the pollution is reduced.
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Paragraph 0061-0062
(2017/04/25)
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- Cycloaracylation of Enamines, I. - Synthesis of 4-Quinolone-3-carboxylic Acids
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Starting with o-halobenzoyl chlorides 4 and open-chain secondary enamines 5, a new synthesis of 4-quinolone-3-carboxylic acids 12 is described.The reaction of 7-haloquinolone-3-carboxylic acids 12a-k with aliphatic amines 14 produces highly active antibacterial 7-aminoquinolone-3-carboxylic acids 15.The main product of the 1-cyclopropyl series, "ciprofloxacin" (15a), is being developed as a broad-spectrum chemotherapeutic agent.
- Grohe, Klaus,Heitzer, Helmut
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