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Method for preparing 2,6-diacetyl pyridine

A technology of diacetylpyridine and diethyl pyridinedicarboxylate, which is applied in the direction of organic chemistry, can solve the problems of product failure, cumbersome operation, and yield decline, and achieve product yield improvement, simplification of experimental operations, and The effect of shortening the reaction time

Inactive Publication Date: 2008-04-09
SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] There are two main synthetic methods of 2,6-diacetylpyridine, one is using sodium ethoxide as alkaline reagent, 2,6-pyridinedicarboxylate diethyl and ethyl acetate carry out Claisen condensation, and then hydrolysis decarboxylation Obtain; This method is loaded down with trivial details, time-consuming longer (Luches R., Pergal M.Coll.Czech.Chem.Commun., 1959,24,36); Especially the alkaline reagent sodium ethylate that uses is to obtain with the reaction of ethanol and sodium , it needs to be absolutely dry when used, and the ethyl acetate as the reaction raw material also needs to be treated to remove the ethanol in it. A small amount of ethanol or water in the reaction system will cause the yield to drop sharply, and even the product cannot be obtained.

Method used

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  • Method for preparing 2,6-diacetyl pyridine
  • Method for preparing 2,6-diacetyl pyridine
  • Method for preparing 2,6-diacetyl pyridine

Examples

Experimental program
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Embodiment 1

[0018]

[0019] In a 250ml three-necked flask, add 1.115g (0.005mol) of pyridine diester, 20ml of ethyl acetate and 20ml of toluene in sequence, and add 0.575g (0.025mol) of sodium metal while stirring. After the sodium metal is completely dissolved, heat up to 120°C and reflux for 8 -9h, then add 20ml of water and 20ml of concentrated hydrochloric acid, react at 120°C for 4h, stop the reaction, adjust the pH of the mixture to neutral with sodium carbonate or sodium bicarbonate, then extract with ether 3-4 times, combine the solutions with anhydrous Na 2 SO 4 After drying, the solvent was evaporated and recrystallized with anhydrous methanol to obtain 0.717 g of white crystals with a yield of 88%. 1 HNMR (300MHz, CDCl 3 ,) δ8.20(d, 2H, Py-Hm), 8.04(t, 1H, Py-Hp), 2.81(s, 6H, O=C(CH 3 )).Anal.Calcd for C 9 h 9 NO 2 : C, 66.25; H, 5.56; N, 8.58. Found: C, 66.25; H, 5.52; N, 8.73.mp 79°C.

Embodiment 2

[0021] Add 1.115g (0.005mol) of pyridine diester, 20ml of ethyl acetate and 30ml of toluene to a 250ml three-necked flask, and add 0.69g (0.03mol) of sodium metal while stirring. After the sodium metal is completely dissolved, heat up to 120°C and reflux for 8- 9h, then add 20ml of water and 20ml of concentrated hydrochloric acid, react at 120°C for 4h, stop the reaction, adjust the pH of the mixture to neutral with sodium carbonate or sodium bicarbonate, then extract with ether 3-4 times, combine the solutions with anhydrous Na 2 SO 4 After drying, the solvent was evaporated and recrystallized with anhydrous methanol to obtain 0.701 g of white crystals with a yield of 86%. 1 HNMR (300MHz, CDCl 3 ,) δ8.20(d, 2H, Py-Hm), 8.04(t, 1H, Py-Hp), 2.81(s, 6H, O=C(CH 3 )).Anal.Calcd for C 9 h 9 NO 2 : C, 66.25; H, 5.56; N, 8.58. Found: C, 66.23; H, 5.55; N, 8.62.mp 79°C.

Embodiment 3

[0023] Add 1.115g (0.005mol) of pyridine diester and 30ml of ethyl acetate into a 250ml three-necked flask, and add 0.80g (0.02mol) of calcium metal while stirring. After the calcium metal is completely dissolved, heat up to 100°C and reflux for 8 hours, then slowly add 20ml Water and 20ml of concentrated hydrochloric acid were reacted at 120°C for 4 hours, and the reaction was stopped. The excess acid was neutralized with sodium carbonate, and then extracted with ether for 3-4 times. After combining the solutions, use anhydrous Na 2 SO 4 After drying and evaporating the solvent, it was purified with a silica gel column. The developing solvent was petroleum ether: ethyl acetate (5:1) to obtain 0.75 g of white crystals with a yield of 92%. 1 HNMR (400MHz, CDCl 3 ,) δ8.20(d, 2H, Py-Hm), 8.04(t, 1H, Py-Hp), 2.81(s, 6H, O=C(CH 3 )).Anal.Calcd for C 9 h 9 N0 2 : C, 66.25; H, 5.56; N, 8.58. Found: C, 66.20; H, 5.58; N, 8.63.mp 79.5°C.

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Abstract

The invention relates to a preparative method of 2, 6-diacetylpyridine. By adopting alkali metal or alkaline earth metal as the alkaline reagent, the method carries out the Claisen condensation to 2, 6-pyridine dicarboxylic aid diethyl ester and ethyl acetate to gain the 2, 6-diacetylpyridine. Specifying in the formulate on the right, compared with other methods, the method provided in the invention needs not to conduct special treatment for the reaction raw materials and the alkaline reagents. The minor water or ethanol in the reaction system has no distinct influence to the reaction, and the reaction system cancels drying and purifying treatment in order to simplify the experimental operation, reduce the reaction period, save cost, improve the output rate of the product and demonstrate good applicable valve.

Description

technical field [0001] The invention discloses a method for preparing 2,6-diacetylpyridine and an alkaline reagent used therein. It belongs to the technical field of organic chemistry and also belongs to the technical field of organic fine chemicals. Background technique [0002] 2,6-Diacetylpyridine (DAP for short), molecular formula C 9 h 9 NO 2 , white needle-like or flaky crystals, melting point 79°C, is a very important organic intermediate, mainly used in the synthesis of olefin polymerization catalysts, the synthesis of pharmaceutical intermediates and bioengineering and other fields. [0003] A very important use of 2,6-diacetylpyridine is to generate pyridine bis-imine Schiff base ligands with substituted anilines, and form catalysts with transition metals such as iron and cobalt, which are the successors to the first generation of Ziegler-Natta catalysts , a new generation of high-efficiency olefin polymerization catalysts after the second-generation metallocen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/50
Inventor 谢光勇张东方
Owner SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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