2402-77-9Relevant articles and documents
A PROCESS FOR THE PREPARATION OF SUBSTITUTED PYRIDINE COMPOUNDS AND INTERMEDIATES THEREOF
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Page/Page column 28-29, (2022/04/03)
The present invention discloses a process for the preparation of substituted pyridine compounds of formula (I), comprises a step in which vinylogous nitriles of formula (II), are obtained from substituted α,β-unsaturated nitrile compounds of formula (III), and a further step of converting the vinylogous nitrile compounds of formula (II) into substituted pyridines of formula (I); wherein R1, R2, R3, R4 and LG are as defined in the description.
Preparation method of 2, 3-dichloropyridine
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Paragraph 0015-0026, (2021/04/03)
The invention relates to a preparation method of 2, 3-dichloropyridine, which comprises the following steps: by using 2, 3, 6-trichloropyridine and hydrogen as raw materials, carrying out catalytic hydrogenation reaction in the presence of a heterogeneous catalyst and an acid-binding agent to obtain 2, 3-dichloropyridine, wherein the active component of the heterogeneous catalyst is palladium, thecarrier of the heterogeneous catalyst is gamma-Al2O3, and the acid-binding agent is transition metal acetate.
One-pot method 2 and 3 -dichloropyridine synthesis method
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Paragraph 0036-0073, (2021/08/25)
The invention discloses a one-pot method 2 and 3 -dichloropyridine synthesis method, and belongs to the technical field of chloropyridine synthesis. The method comprises the following steps: (1) heating dehydration of dichloromethane and 3 - aminopyridine, dropping the excess chloride sulfoxide, refluxing the temperature, and preserving 5 - 8 hours. (2) Chromatography Tracking 3 - aminopyridine content is less 0.3%, cooling to -10 - 5 °C, dropping into sodium hydroxide, pH9 - 10, maintaining -10 - 5 °C, dropwise adding sodium nitrite solution and cuprous chloride, and completing heat preservation 4 - 6 hours after completion. (3) Warm up to 40 - 50 °C, keep warm 2 - 4 hours, concentrate, freeze, centrifuging and dry, obtain the finished product. In the step (1), 3 - aminopyridine is chlorinated by using thionyl chloride as a chlorinating agent to generate a product. In the step (2), cuprous chloride is used as a chlorination reaction catalyst to carry out diazotization reaction under the action of sodium nitrite as oxidant Sandmeyer.