- Sitafloxacin three membered ring intermediate preparation method
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The invention discloses a preparation method for a three-membered ring intermediate of sitafloxacin hydrate. The preparation method comprises the following steps: dimethyl malonate and 1,1,2-tribromo-2-fluoroethane react to synthesize a solid A, the solid A is subjected to debromination to prepare an oily liquid B, the oily liquid B is subjected to branched chain removal to prepare a solid C, the solid C is hydrolyzed to prepare a solid D, the solid D is subjected to chiral resolution with L-leucinamide and reduced to prepare a solid F, the solid F is introduced to an amino group and combined with p-toluenesulfonic acid to prepare the three-membered ring intermediate of sitafloxacin hydrate. The preparation method has fewer steps for preparing the three-membered ring intermediate of sitafloxacin hydrate, unnecessary isomer is separated by one step with the chiral resolution method, the product yield and purity are higher, and scale production is easier.
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Paragraph 0038-0064
(2017/07/07)
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- Method for preparing cis-1-amino-2-fluorocyclopropane
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The invention provides a method for preparing cis-1-amino-2-fluorocyclopropane. A preparation process comprises 8 to 10 steps. A structural formula of the cis-1-amino-2-fluorocyclopropane is represented by a formula 1 shown in the description, and the form of benzene sulfonate or hydrochloride is relatively common. An important intermediate product, i.e., cis-fluoro-amine olefin 2 is synthesized. The method has the advantages that the consumption of diiodo-fluoromethane or dibromo-fluoromethane, which is expensive in price and causes heavy pollution in a raw material production process, is avoided; a cis triatomic ring is obtained through the cyclization of high-activity cis-olefin 2, and an absolute-configuration product can be obtained by only one-time resolution, so that the method has especially great advantages in the aspect of either economical efficiency of the raw materials, or the difficulty of resolution of isomers.
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Page/Page column 10; 12
(2016/12/22)
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- Stereoselective synthesis of cis -2-fluorocyclopropanecarboxylic acid
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A rhodium-catalyzed cyclopropanation of 1-fluoro-1-(phenylsulfonyl)ethylene and diazo esters is described as an effective method for the stereoselective synthesis of cis-2-fluorocyclopropanecarboxylic acid. This process provides an example of the cyclopro
- Shibue, Taku,Fukuda, Yasumichi
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p. 7226 - 7231
(2014/08/18)
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- Synthesis of cis-2-fluorocyclopropylamine by stereoselective cyclopropanation under phase-transfer conditions
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cis-2-Fluorocyclopropylamine is stereoselectively synthesized by cyclopropanation of 3-aryl-2-vinyl-3-(methoxy)isoin-dol-1-one by treating dibromofluoromethane with saturated aqueous KOH solution in the presence of 18-crown-6 in dichloromethane, followed by removal of a bromine atom of the formed bromofluorocyclopropane derivative with Raney Ni, and successive three steps-deprotection procedures for generating an amino group on the cyclopropane ring.
- Matsuo, Jun-Ichi,Tani, Yu-Ichirou,Hayakawa, Yu-Ichirou
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p. 464 - 465
(2007/10/03)
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- Synthetic studies on the key component of the new generation of quinolonecarboxylic acid, DU-6859. 1. Synthesis of (1R,2S)-2-fluorocyclopropylamine by the use of optical resolution
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The title synthesis was achieved by employing highly cis-selective cyclopropanation of N-benzyl-N-vinylcarbamates with zinc-monofluorocarbenoid, deprotection of the formed N-benzyl-N-(cis-2-fluorocyclopropyl)carbamates, and optical resolution of the resul
- Tamura, Osamu,Hashimoto, Masaru,Kobayashi, Yuko,Katoh, Tadashi,Nakatani, Kazuhiko,Kamada, Masahiro,Hayakawa, Isao,Akiba, Toshifumi,Terashima, Shiro
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p. 3889 - 3904
(2007/10/02)
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- Synthetic Studies on the Key Component of the New Generation of Quinolonecarboxylic Acid, DU-6859. 2. Asymmetric Synthesis of (1R,2S)-2-Fluorocyclopropylamine
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The title synthesis was achieved by featuring diastereoface-selective cyclopropanation of (4R,5S)-4,5-diphenyl-3-vinyl-2-oxazolidinone and its related compounds, the chiral conformationally rigid N-vinylcarbamates, with zinc-monofluorocarbenoid, followed
- Akiba, Toshifumi,Tamura, Osamu,Hashimoto, Masaru,Kobayashi, Yuko,Katoh, Tadashi,et al.
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p. 3905 - 3914
(2007/10/02)
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- Asymmetric Synthesis of (1R,2S)-2-Fluorocyclopropylamine, the Key Intermediate of the New Generation of Quinolonecarboxylic Acid, DU-6859
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The title synthesis was achieved by featuring diastereoface selective cyclopropanation of (4R,5S)-4,5-diphenyl-3-vinyl-2-oxazolidinone, the chiral and conformationally rigid N-vinylcarbamate, with zincmonofluorocarbenoid followed by hydrogenolysis of form
- Tamura, Osamu,Hashimoto, Masaru,Kobayashi, Yuko,Katoh, Tadashi,Nakatani, Kazuhiko,et al.
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p. 3487 - 3490
(2007/10/02)
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- Synthesis and optical resolution of dl-cis-2-fluorocyclopropylamine, the key component of the new generation of quinolonecarboxylic acid, DU-6859
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The title synthesis was accomplished by featuring highly cis-selective cyclopropanation of an N-vinylcarbamate with zinc-monofluorocarbenoid followed by deprotection of the formed N-(cis-2-fluorocyclopropyl)carbamate. Optical resolution of dl-cis-2-fluoro
- Tamura,Hashimoto,Kobayashi,Katoh,Nakatani,Kamada,Hayakawa,Akiba,Terashima
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p. 3483 - 3486
(2007/10/02)
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