- Preparation method of 2, 5-dibromo-3-methylpyridine
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The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of 2, 5-dibromo-3-methylpyridine. The preparation method comprises the following steps: (1) adding 2-amino-3-methylpyridine and acetic anhydride into a four-neck flask, heating to reflux, and carrying out thin-layer chromatography tracking reaction; (2) when the temperature of a reaction liquid obtained in the step (1) is reduced to 20-25 DEG C, dropwise adding liquid bromine, reacting for 2-3 hours at 50-60 DEG C after dropwise adding of liquid bromine, adding water until all solids are dissolved, dropwise adding a sodium hydroxide solution, continuously reacting for 30 minutes after dropwise adding, and carrying out suction filtration, drying and recrystallization to obtain 2-amino-3-methyl-5-bromopyridine; and (3) adding the obtained 2-amino-3-methyl-5-bromopyridine into a hydrogen bromide solution, dropwise adding a saturated sodium nitrite solution under the catalysis of cuprous bromide, controlling the temperature to be -5 to 10 DEG C, and reacting for 2 to 4 hours to obtain 2, 5-dibromo-3-methylpyridine. The method provided by the invention has the beneficial effects ofmild reaction conditions, high yield, low cost and short process route, and is suitable for industrial production.
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Paragraph 0017; 0020-0021; 0023-0024; 0026-0027
(2020/03/09)
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- A 2, 5 - dibromo -3 - methyl pyridine preparation method (by machine translation)
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The invention belongs to the field of organic synthesis, in particular relates to a 2, 5 - dibromo - 3 - methyl pyridine preparation method, comprises the following steps: (1) the 2 - amino - 3 - methyl pyridine and acetic anhydride is added to the four flasks, heating to reflux, thin-layer chromatography the tracking reaction; (2) step (1) of reaction fluids in a temperature drop to 20 - 25 °C when, [...], paused, 50 - 60 °C reaction 2 - 3 h, to all solid-dissolving after adding water, sodium hydroxide solution, after adding continue to reaction 30 min, filtering, drying, recrystallize to get 2 - amino 3 - methyl - 5 - bromo pyridine; (3) the 2 - amino - 3 - methyl - 5 - bromo pyridine is added in a solution of hydrogen bromide, in the catalysis of cuprous bromide, [...] and sodium nitrite solution, temperature control in the - 5 - 10 °C, reaction 2 - 4 h, shall be 2, 5 - dibromo - 3 - methyl pyridine. The method of the invention is beneficial effect: mild reaction conditions, high yield, low cost, the process route is short, it is suitable for industrial production. (by machine translation)
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Paragraph 0017; 0020; 0021; 0023; 0024; 0026; 0027
(2019/05/28)
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- Efficient synthesis of 2-substituted 7-azaindole derivatives via palladium-catalyzed coupling and C-N cyclization using 18-crown-6
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A practical and straightforward preparation of various novel 2-substituted 7-azaindole derivatives from 2-amino-3-iodopyridine by a two-step procedure is described that gives the desired compounds in good overall yields. Georg Thieme Verlag Stuttgart.
- De Mattos, Marcos Carlos,Alatorre-Santamaria, Sergio,Gotor-Fernandez, Vicente,Gotor, Vicente
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p. 2149 - 2152
(2008/03/28)
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- Carboxamidation of pyridines by the system of elemental fluorine- carbonitrile-water: A useful alternative to the chichibabin amination
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The title reaction with pyridine, 4-methylpyridine, 3-methylpyridine, 3- bromopyridine, nicotinonitrile, and quinoline yields 2-carboxamido derivatives regioselectively. Isoquinoline is amidated at position 1.
- Kiselyov,Strekowski
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p. 2387 - 2392
(2007/10/02)
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