Preparation method of 2,6-pyridinedicarboxylic acid_Industrial additive

Background and overview of preparation methods of 2,6-pyridinedicarboxylic acid

2,6-pyridinedicarboxylic acid derivatives and other organic ligands such as salicylic acid derivatives , o-phenanthroline ligands and β-diketone compounds have stronger sensitizing luminescence capabilities. At the same time, using some rare earth complexes of 2,6-pyridinedicarboxylic acid as chiral molecules, more information can be obtained by measuring the circularly polarized luminescence spectrum.

2,6-pyridinedicarboxylic acid can be used to prepare 2,6-pyridine dimethanol. 2,6-disubstituted pyridine is an important class of organic synthesis intermediates, especially 2,6-pyridine. Dimethanol is very versatile. The hydroxyl group can be derivatized into aldehyde groups, halogenated hydrocarbons, amino groups and many other functional groups to synthesize other important compounds. Moreover, due to the substitution of 2 and 6 positions, macrocyclic compounds can also be generated, which are widely used in synthesis and have high research value.

Preparation method of 2,6-pyridinedicarboxylic acid

Preparation method report of 2,6-pyridinedicarboxylic acid 1.

In a 2L flask equipped with a stirrer and a reflux condenser, add 800mL water and 53.5gKMnO₄ , 16.7g 2,6-lutidine, heated to reflux, when the color of KMnO4 fades, add another 53.5gKMnO₄ and 200mL water, continue to reflux until the color fades completely (about 2h), cool, filter out MnO₂, wash the filtered insoluble matter in 500mL of hot water, filter, combine the filtrate, concentrate the filtrate to 200-300mL, filter, and then Acidify with concentrated HCl, cool, precipitate out, filter, and dry to obtain 2,6-pyridinedicarboxylic acid. Yield: 80%, m.p. 220°C, consistent with literature.

Preparation method report 2 of 2,6-pyridinedicarboxylic acid.

(1) Dissolve 2-methyl-6-carboxylic acid pyridine in In pyridine, add potassium permanganate solution dropwise to the reaction solution and stir continuously. After the dropwise addition is completed, heat the reaction for 10 hours to obtain a mixed solution. The heating temperature is 87°C;

(2) Go to Add sulfuric acid dropwise to the mixed liquid obtained in step (1), stir and adjust the pH value to 2.3, precipitate out and filter to obtain 2,6-pyridinedicarboxylic acid.

Preparation method and application of 2,6-pyridinedicarboxylic acid

Preparation of 2,6-pyridine dimethanol tetrahydrofurancarboxylic acid from 2,6-pyridinedicarboxylic acid The method is as follows:

Add 8.8g (0.05mol) of 2,6-pyridinedicarboxylic acid and 200mLTHF into a 500mL three-necked bottle of carbonic acid, cool to -5 degrees Celsius in an ice-salt bath, and add 3.8g ( 0.1mol) NaBH4. After the addition is complete, react for half an hour until gas is no longer generated. Dissolve 0.05 mol of iodine in 80 mL of THF and drop it into it. After the dropwise addition, remove the ice bath and naturally warm to room temperature. The reaction will stop after 1.5 hours. Add 3 mol/L hydrochloric acid to adjust the pH to neutral, remove the solid by suction filtration, spin the solution to dryness, extract with vibration with ethyl acetate, dry with anhydrous magnesium sulfate and then spin evaporate to obtain 5g of white crystals with a yield of 72%. m.p.111-112℃, consistent with literature.

References

[1] [Chinese invention] CN201410696815.8 A preparation method of 2,6-pyridine dimethanol

[2] [China Invention] CN201310646407.7 A preparation method of 2,6-pyridinedicarboxylic acid