- Synthetic method for ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate
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The invention discloses a synthetic method for ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate. The method is characterized by comprising the following steps: a, performing chlorination on diketene, and performing alcoholysis to synthesize ethyl 4-chloroacetoacetate; b, performing oximation on the ethyl 4-chloroacetoacetate to synthesize ethyl 4-chloro-2-(hydroxyimino)-3-oxobutanoate; c, performing a reaction on the ethyl 4-chloro-2-(hydroxyimino)-3-oxobutanoate and thiourea to synthesize ethyl 2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetate; and d, performing hydrocarbonylation on the ethyl2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetate to synthesize the ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate. The method has the following advantages: 1, the chlorination reaction in the stepa is a continuous reaction, and has a fast reaction speed and no accumulation of a large amount of dangerous materials, so that the danger is small; 2, the costs of equipment are lower, the equipmentis conventional organic synthesis equipment, no expensive and special equipment is needed, so that the equipment is easy to copy, and the production efficiency is improved; and 3, the diketene is directly used as a raw material, the raw material cost is low, the synthetic steps are simple to operate, so that the method facilitates reducing the production costs of the ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate.
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Paragraph 0016; 0017
(2020/01/12)
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- Method for synthesizing ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate
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The invention relates to a method for synthesizing ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate, and belongs to the technical field of the preparation of antibiotic drug intermediates. The method provided by the invention comprises the following steps: using ethyl acetoacetate, sodium nitrite and concentrated sulfuric acid as raw materials; using purified water as a solvent; performing oximation reaction first, and then performing halogenation reaction; then adding thiourea; using 12-ammonium phosphomolybdate (AMP) as the catalyst, and using methanol as a solvent to perform cyclization reaction, thereby obtaining ethyl2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate. The method provided by the invention is simple in process, shortens the reaction cycle, increases the reaction yield, and reduces corrosion to equipment; the used catalyst is separated from the product easily and can be reused, thereby reducing the production cost, greatly reducing the 'three wastes' pollution, and having an extremely high industrial application value.
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Paragraph 0011; 0035; 0036; 0042; 0043; 0049; 0050
(2017/07/21)
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- One-pot ceftazidime side-chain acid ethyl ester synthesis method
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The invention relates to a preparation method of a pharmaceutical intermediate, in particular to a one-pot ceftazidime side-chain acid ethyl ester synthesis method. The method comprises the following steps that 1, ethyl 4-bromoacetoacetate is dissolved in water, a sodium nitrite water solution and 15%-25% of sulfuric acid are added dropwise, heat preservation reaction is performed after adding is completed dropwise, extraction is performed after the reaction is completed, the extracting solution is washed with a saturated potassium or sodium carbonate solution, and distillation is performed to obtain an oximation solution; 2, thiourea is added into a water and methanol mixed solution, and then the oximation solution is added dropwise to obtain an ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate solution; 3, the pH of the ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate solution is regulated, then tert-butyl alpha-bromoisobutyrate and a phase transfer catalyst are added for heat preservation reaction, and after the reaction is completed, cooling and suction filter are performed to obtain the ceftazidime side-chain acid ethyl ester. The simple processing of the product is simple, the purity and the yield are high, and the yield is up to 96.5% or above.
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- CARBACEPHEM β-LACTAM ANTIBIOTICS
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Carbacephem -lactam antibiotics having structure (I) are disclosed, including stereoisomers, pharmaceutically acceptable salts, esters and prodrugs thereof, wherein Ar1, Ar2, R1 and R2 are as defined herein. The compounds are useful for the treatment of bacterial infections, in particular those caused by methicillin-resistant Staphylococcus spp.
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Page/Page column 66
(2010/04/06)
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- Thiazolylacetamido cephalosporin type compounds
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Novel cephem compounds of the formula; STR1 wherein R1 represents amino or hydroxyl group which may be protected, R2 represents amino or hydroxyl group or a group convertible into these groups, R3 represents hydrogen or methoxy group or a group convertible into methoxy group, R4 represents hydrogen or a residue of a nucleophilic compound and R8 represents hydrogen or a halogen, or a pharmaceutically acceptable salt or ester thereof, have strong antibiotic properties against a wide variety of microorganisms including gram-positive bacteria as well as gram-negative ones, especially by oral administration and can be used as therapeutic agent for various bacterial infections of animals including human beings.
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