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Preparation method of 2-acetylpyridine

A technology of acetylpyridine and picolinic acid is applied in the field of preparation of 2-acetylpyridine and achieves the effects of high yield, less three wastes and mild reaction conditions

Active Publication Date: 2019-03-22
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The document reports that the yield of 2-acetylpyridine is 25.2%, in fact the applicant repeats the test product yield according to the document method is only 5%

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Add 1.23 kg (10 mol) of p-2-pyridinecarboxylic acid, 57.8 mL of N,N-dimethylformamide, and 10 L of toluene into a reaction flask equipped with a drying tube and an exhaust gas absorption device, stir to raise the temperature to 60°C, and dropwise add 1.78 kg (15.0 mol) of thionyl chloride, after dropping, heat up to reflux for about 2-3 hours, no obvious bubbles are released from the tail gas absorption device, cool to room temperature, and distill off excess thionyl chloride and toluene under reduced pressure to obtain light yellow The oil (2-pyridinecarbonyl chloride, formula II) was directly used in the next reaction;

[0034] Add 2.16 kg (10 mol) of di-tert-butyl malonate, 500 g of anhydrous calcium chloride, 10.0 L of ethyl acetate, and 2.0 L of triethylamine into the reaction flask. , heat up to 60°C and react for about 1-2h, thin-layer chromatography (TLC) detects the end of the reaction, cool down, adjust the pH to 5-6 with hydrochloric acid, separate the organi...

Embodiment 2

[0037] Add 12.3 g (0.1 mol) of 2-pyridinecarboxylic acid, 1.0 ml of triethylamine, and 100 mL of benzene into a reaction flask equipped with a drying tube and an exhaust gas absorption device, stir and raise the temperature to 60°C, and dropwise add 17.8 g (0.15 mol) of chlorinated Thionoxide, after dropping, heat up to reflux reaction for about 2-3 h, no obvious bubbles are released from the tail gas absorption device, cool to room temperature, and distill off excess thionyl chloride and toluene under reduced pressure to obtain light yellow oil (2-pyridine Formyl chloride, formula II), directly used in the next step reaction;

[0038]Add 21.6 g (0.1 mol) of di-tert-butyl malonate, 5.0 g of anhydrous calcium chloride, 100 mL of ethyl acetate, and 20.0 mL of triethylamine into the reaction flask, stir well, then drop into the light yellow oily solution from the previous step Raise the temperature to 60°C and react for about 1-2 h, TLC detects the end of the reaction, cool down,...

Embodiment 3

[0041] Add 12.3 g (0.1 mol) of 2-pyridinecarboxylic acid, 0.95 mL of N, N-dimethylaniline, and 100 mL of benzene into a reaction flask equipped with a drying tube and an exhaust gas absorption device, stir and raise the temperature to 60°C, and add 20.6 g of (0.15mol) phosphorus trichloride, after dropping, heat up to reflux reaction for about 2-3 hours, no obvious bubbles are released from the tail gas absorption device, cool to room temperature, and distill off excess phosphorus trichloride and benzene under reduced pressure to obtain light yellow The oil (2-pyridinecarbonyl chloride, formula II) was directly used in the next reaction;

[0042] Add 21.6g (0.1 mol) of di-tert-butyl malonate, 5g of anhydrous calcium chloride, 100mL of ethyl acetate, and 20mL of triethylamine into the reaction flask. After stirring thoroughly, drop in the light yellow oil from the previous step and heat up React at 60°C for about 1-2 h, TLC detects that the reaction is complete, cool, adjust th...

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PUM

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Abstract

The invention discloses a preparation method of 2-acetylpyridine. The preparation method comprises the following steps: (1) with 2-picolinic acid as a raw material, adding a first inert solvent and acatalyst, stirring and heating to 55-65 DEG C, dropwise adding a chlorinating agent, heating until a reflux reaction is occured, and performing reduced pressure distillation to obtain 2-pyridinecarbonyl chloride; (2) adding an inorganic salt catalyst, a second inert solvent, an alkaline substance and dialkyl malonate in a reaction bottle, sufficiently stirring, dropwise adding the 2-pyridinecarbonyl chloride, performing a heating reaction, neutralizing with hydrochloric acid, separating out an organic layer, washing with saturated sodium bicarbonate and a saturated salt solution in sequence, drying, and performing vacuum concentration to obtain 2-pyridinecarbonyl Di-tert-Butyl malonate; and (3) adding the 2-pyridinecarbonyl Di-tert-Butyl malonate in a mixed solution of water, organic acidand inorganic acid to perform a reflux reaction, regulating to be neutral with alkaline liquid, extracting with an organic solvent, and performing vacuum concentration to obtain 2-acetylpyridine. Thepreparation method has the advantages of being simple in raw materials, simple in operation, mild in condition, high in yield and small in pollution.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of 2-acetylpyridine. Background technique [0002] 2-Acetylpyridine has the aroma of popcorn and tobacco, and is widely used as flavor additives in the beverage, candy, meat products, baked food and cigarette industries, and has a large market demand. In addition, 2-acetylpyridine is also an important intermediate in the fields of organic synthesis and drug synthesis, and is widely used. [0003] The preparation method about 2-acetylpyridine mainly contains: [0004] Oxidation method: This method uses 2-ethylpyridine or (1-hydroxy) ethylpyridine as a raw material, using tert-butyl nitrite (KangY. B., et al., CN107011133; Hu Y. K. et al., Catalysis Communications. 2016,83, 82-87) or tert-butyl hydroperoxide (Tan, J. J, et al., RSC Advances, 2017, 7, 15176-15180). Raw materials for the above methods are rare, and the large-scale use of such oxidants has seri...

Claims

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Application Information

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IPC IPC(8): C07D213/50
CPCC07D213/50
Inventor 朱锦桃洪小平赵飞
Owner ZHEJIANG SCI-TECH UNIV
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