17117-19-0Relevant articles and documents
Synthesis method of 2, 5-dimethyl-3-bromopyridine
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Paragraph 0023; 0026-0027; 0030; 0031; 0034, (2020/03/09)
The invention relates to the field of organic chemistry, in particular to a synthesis method of 2, 5-dimethyl-3-bromopyridine. The synthesis method comprises the following steps: 1, reacting diethyl malonate with an alkali metal to generate a salt, dropwisely adding a toluene solution of 2 methyl-3-nitro-5-chloropyridine to perform condensation reaction, and decarboxylating under acidic conditionsto obtain 2, 5-dimethyl-3-nitropyridine; 2, carrying out hydrogenation reduction, suction filtration and filtrate concentration on the obtained 2, 5-dimethyl-3-nitropyridine by taking methanol as a solvent under the catalysis of Pd/C so as to obtain 2, 5-dimethyl-3-aminopyridine;, and 3, reacting the obtained 2, 5-dimethyl-3-aminopyridine with an acid to generate a salt, cooling to -9 DEG C to 4DEG C, dropwise adding liquid bromine, dropwise adding a sodium nitrite aqueous solution after dropwise adding of liquid bromine, adjusting the pH value of an obtained solution to be higher than 7 after dropwise adding of the sodium nitrite aqueous solution, and then extracting, drying and concentrating to obtain 2, 5-dimethyl-3-bromopyridine. The method provided by the invention has the beneficial effects of mild reaction conditions, high yield, easily available raw materials, low cost, short process route and an industrial prospect.
A 2, 5 - dimethyl -3 - bromo pyridine synthesis method
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Paragraph 0020; 0023; 0026; 0027; 0030; 0031; 0034, (2019/05/28)
The invention relates to the field of organic chemistry, in particular to a 2, 5 - dimethyl - 3 - bromo pyridine synthesis method, comprises the following steps: 1, malonic acid diethyl ester and alkali metal reaction to produce salt, then dropwise 2 methyl - 3 - nitro - 5 chloro pyridine to a toluene solution of a condensation reaction, after decarboxylation under acidic conditions shall be 2, 5 - dimethyl - 3 - nitro pyridine; 2, 2, 5 - dimethyl - 3 - nitro pyridine in under the catalysis of the Pd/C, methanol as the solvent, hydrogen reduction, filtered, the filtrate is concentrated, shall be 2, 5 - dimethyl - 3 - aminopyridine; 3, 2, 5 - dimethyl - 3 - aminopyridine first with an acid generating salt, cooling to - 9 °C - 4 °C, [...], drops the instillment sodium nitrite aqueous solution, pH adjusting solution is dropped is alkaline, and then extracted, drying, concentration, shall be 2, 5 - dimethyl - 3 - bromo pyridine. The method of the invention is beneficial effect: mild reaction conditions, high yield, and raw materials are easy, and the cost is low, the process route is short, and has industrial prospects.
A 2, 5 - dimethyl - 3 - bromo pyridine synthesis method (by machine translation)
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Paragraph 0023; 0026; 0030; 0034, (2017/09/26)
The invention relates to the field of organic chemistry, in particular to a 2, 5 - dimethyl - 3 - bromo pyridine synthesis method, comprises the following steps: 1, malonic acid diethyl ester and alkali metal reaction to produce salt, then dropwise 2 methyl - 3 - nitro - 5 chloro pyridine to a toluene solution of a condensation reaction, after decarboxylation under acidic conditions shall be 2, 5 - dimethyl - 3 - nitro pyridine; 2, 2, 5 - dimethyl - 3 - nitro pyridine in under the catalysis of the Pd/C, methanol as the solvent, hydrogen reduction, filtered, the filtrate is concentrated, shall be 2, 5 - dimethyl - 3 - aminopyridine; 3, 2, 5 - dimethyl - 3 - aminopyridine first with an acid generating salt, cooling to - 9 °C - 4 °C, instillment fluid bromine, drops the instillment sodium nitrite aqueous solution, pH adjusting solution is dropped is alkaline, and then extracted, drying, concentration, shall be 2, 5 - dimethyl - 3 - bromo pyridine. The method of the invention is beneficial effect: mild reaction conditions, high yield, and raw materials are easy, and the cost is low, the process route is short, and has industrial prospects. (by machine translation)