Preparation method of 2,6-pyridinedimethanol

Abstract

The invention relates to a preparation method of a compound 2,6-pyridinedimethanol. The preparation method comprises the steps: a raw material 2,6-dimethylpyridine is oxidized by using potassium permanganate, 2,6-pyridinedicarboxylic acid is generated and is reduced by a sodium borohydride / iodine system, and the 2,6-pyridinedimethanol with higher yield is obtained. Compared with the prior art, the method has the advantages that the steps are simplified, the reaction condition is mild, the operation is safe, simple and convenient, the products are easy to separate, the yield is higher and the like.

Description

technical field

[0001] The invention relates to a chemical intermediate and its preparation technology, in particular to a preparation method of 2,6-pyridinedimethanol. Background technique

[0002] 2,6-disubstituted pyridines are a class of important intermediates in organic synthesis, especially 2,6-pyridinedimethanol has strong applicability. Hydroxy groups can be derivatized into many other functional groups such as aldehyde groups, halogenated hydrocarbons, amino groups, etc., and then synthesize other important compounds. Moreover, due to the substitution of the 2 and 6 positions, macrocyclic compounds can also be generated, which are widely used in synthesis and have high research value.

[0003] At present, the more classic route of synthesizing 2,6-pyridinedimethanol is to use 2,6-lutidine as raw material, oxidize it to 2,6-pyridinedicarboxylic acid, then carry out esterification, and then reduce the ester to alcohol , to obtain the target product. This synthetic...

Examples

Embodiment 1

[0009] (1) Synthesis of 2,6-pyridinedicarboxylic acid:

[0010] In a 2L flask equipped with a stirrer and a reflux condenser, add 800mL of water, 53.5g of KMnO 4 , 16.7g2,6-lutidine, heated to reflux, when KMnO 4 When the color fades, add another 53.5gKMnO 4 And 200mL water, continue to reflux until the color fades completely (about 2h), cool, filter out MnO 2 , the filtered insoluble matter was washed in 500 mL of hot water, filtered, and the filtrate was combined, the filtrate was concentrated to 200-300 mL, filtered, then acidified with concentrated HCl, cooled, a precipitate was precipitated, filtered, and dried to obtain 2,6 - picolinic acid. Yield: 80%, m.p. 220°C, consistent with literature.

[0011] (2) Synthesis of 2,6-pyridinedimethanol:

[0012] Add 8.8 g (0.05 mol) of 2,6-pyridinedicarboxylic acid and 200 mL THF into a 500 mL three-necked flask, cool to -5 degrees Celsius in an ice-salt bath, and add 3.8 g (0.1 mol) NaBH in batches while stirring. 4 . React ...

Embodiment 2

[0014] (1) Synthesis of 2,6-pyridinedicarboxylic acid:

[0015] In a 500 four-neck flask equipped with a stirrer and a reflux condenser, add 300 mL of water and 10.7 g (0.1 mol) of 2,6-lutidine, and heat to 60 degrees. 0.5molKMnO 4 Add in small amounts in batches, control the temperature at 85-90 degrees, and continue the reaction until the color fades completely (about 2h). Cool, filter out MnO 2 , wash with 100mL of hot water, filter, combine the filtrates, concentrate to 100-130mL, and then acidify with concentrated HCl, cool to precipitate, filter, and dry to obtain 2,6-pyridinedicarboxylic acid. Yield: 78%, m.p. 220°C, consistent with literature.

[0016] 2) Synthesis of 2,6-pyridinedimethanol:

[0017] Add 8.8g (0.05mol) of 2,6-pyridinedicarboxylic acid and 200mLTHF into a 500mL three-necked flask, and add 7.6g (0.2mol) of NaBH in batches under stirring at room temperature 4 . React for half an hour after the addition, until no more gas is generated. Dissolve 0.05...

technical field

[0001] The invention relates to a chemical intermediate and its preparation technology, in particular to a preparation method of 2,6-pyridinedimethanol. Background technique

[0002] 2,6-disubstituted pyridines are a class of important intermediates in organic synthesis, especially 2,6-pyridinedimethanol has strong applicability. Hydroxy groups can be derivatized into many other functional groups such as aldehyde groups, halogenated hydrocarbons, amino groups, etc., and then synthesize other important compounds. Moreover, due to the substitution of the 2 and 6 positions, macrocyclic compounds can also be generated, which are widely used in synthesis and have high research value.

[0003] At present, the more classic route of synthesizing 2,6-pyridinedimethanol is to use 2,6-lutidine as raw material, oxidize it to 2,6-pyridinedicarboxylic acid, then carry out esterification, and then reduce the ester to alcohol , to obtain the target product. This synthetic...

Examples

Embodiment 1

[0009] (1) Synthesis of 2,6-pyridinedicarboxylic acid:

[0010] In a 2L flask equipped with a stirrer and a reflux condenser, add 800mL of water, 53.5g of KMnO 4 , 16.7g2,6-lutidine, heated to reflux, when KMnO 4 When the color fades, add another 53.5gKMnO 4 And 200mL water, continue to reflux until the color fades completely (about 2h), cool, filter out MnO 2 , the filtered insoluble matter was washed in 500 mL of hot water, filtered, and the filtrate was combined, the filtrate was concentrated to 200-300 mL, filtered, then acidified with concentrated HCl, cooled, a precipitate was precipitated, filtered, and dried to obtain 2,6 - picolinic acid. Yield: 80%, m.p. 220°C, consistent with literature.

[0011] (2) Synthesis of 2,6-pyridinedimethanol:

[0012] Add 8.8 g (0.05 mol) of 2,6-pyridinedicarboxylic acid and 200 mL THF into a 500 mL three-necked flask, cool to -5 degrees Celsius in an ice-salt bath, and add 3.8 g (0.1 mol) NaBH in batches while stirring. 4 . React ...

Embodiment 2

[0014] (1) Synthesis of 2,6-pyridinedicarboxylic acid:

[0015] In a 500 four-neck flask equipped with a stirrer and a reflux condenser, add 300 mL of water and 10.7 g (0.1 mol) of 2,6-lutidine, and heat to 60 degrees. 0.5molKMnO 4 Add in small amounts in batches, control the temperature at 85-90 degrees, and continue the reaction until the color fades completely (about 2h). Cool, filter out MnO 2 , wash with 100mL of hot water, filter, combine the filtrates, concentrate to 100-130mL, and then acidify with concentrated HCl, cool to precipitate, filter, and dry to obtain 2,6-pyridinedicarboxylic acid. Yield: 78%, m.p. 220°C, consistent with literature.

[0016] 2) Synthesis of 2,6-pyridinedimethanol:

[0017] Add 8.8g (0.05mol) of 2,6-pyridinedicarboxylic acid and 200mLTHF into a 500mL three-necked flask, and add 7.6g (0.2mol) of NaBH in batches under stirring at room temperature 4 . React for half an hour after the addition, until no more gas is generated. Dissolve 0.05...

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