Preparation method of hydroxyl pyridine compound

A hydroxypyrimidine and compound technology, applied in the direction of organic chemistry, can solve the problems of low solubility, slow reaction speed, low yield, etc., and achieve the effects of increasing solubility, increasing yield and content, and accelerating production speed.

Active Publication Date: 2013-03-20
湖南海利常德农药化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The main reason that causes yield is not high is because the solubility of alkylguanidine (formula II) in organic solvent toluene, xylene or chlorobenzene is not large, causes it to react with α-alkyl acetoacetate alkyl ester (formula III) Speed ​​is very slow, and α-methyl acetoacetate alkyl ester (formula III) easily decomposes under alkaline conditions:

Method used

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  • Preparation method of hydroxyl pyridine compound
  • Preparation method of hydroxyl pyridine compound
  • Preparation method of hydroxyl pyridine compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Example 1: Synthesis of 2,2-dimethylamino-5,6-dimethyl-4-hydroxyl-pyrimidine

[0026] In the 500ml three-necked reaction flask that stirring, thermometer, reflux condenser are housed, add 200ml toluene, 30ml methyl alcohol, start stirring, add 15.0g (0.05mol) metguanidine sulfate and 4.8g (0.115mol) solid sodium hydroxide, After keeping stirring at 20-40°C for 2 hours, start to add 16.4g (0.12mol) methyl a-methyl acetoacetate dropwise, raise the temperature to reflux after dropping, separate the water and methanol, continue to raise the temperature and react until the boiling point of the solvent, and the reaction ends. Cool down to below 100°C, add 30ml of water and 1g of concentrated sulfuric acid, stir for 15 minutes, adjust the pH of the reaction solution to 7, separate the water layer at rest, remove the solvent from the oil layer under reduced pressure to obtain 16.2g of off-white solid product, content: 98.0%, yield : 95.1%.

Embodiment 2

[0027] Example 2: Synthesis of 2,2-dimethylamino-5,6-dimethyl-4-hydroxyl-pyrimidine

[0028] In the 500ml three-necked reaction flask that stirring, thermometer, reflux condenser are housed, add 200ml toluene, 20ml ethanol, start stirring, add 15.0g (0.05mol) metguanidine sulfate and 4.8g (0.115mol) solid sodium hydroxide, Keep stirring at 20-40°C for 2 hours, start to add 18.1g (0.12mol) ethyl a-methyl acetoacetate dropwise, raise the temperature to reflux after dropping, separate the water and ethanol, continue to raise the temperature to react to the boiling point of the solvent, and the reaction ends. Cool down to below 100°C, add 30ml of water and 1.3g of concentrated sulfuric acid, stir for 15 minutes, adjust the pH of the reaction solution to 7, separate the water layer at rest, remove the solvent from the oil layer under reduced pressure to obtain 16.3g of off-white solid product, content: 97.5%, yield Rate: 95.2%.

Embodiment 3

[0029] Example 3: Synthesis of 2,2-dimethylamino-5,6-dimethyl-4-hydroxyl-pyrimidine

[0030] In a 500ml three-neck reaction flask equipped with stirring, thermometer and reflux condenser, add 200ml xylene and 30ml methanol, start stirring, add 15.0g (0.05mol) metguanidine sulfate and 4.8g (0.115mol) solid sodium hydroxide , keep stirring at 20-40°C for 2 hours, start dropwise adding 16.4g (0.12mol) methyl a-methyl acetoacetate, raise the temperature to reflux after dropping, separate the water and methanol, continue to heat up to the boiling point of the solvent, and the reaction is over , cooled to below 100°C, added 30ml of water and 1g of concentrated sulfuric acid, stirred for 15 minutes, adjusted the pH=7 of the reaction solution, separated the water layer at rest, and decompressed the oil layer to remove the solvent to obtain 16.4g of off-white solid product, content: 98.2%. Rate: 96.4%.

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Abstract

The invention discloses a preparation method of a hydroxyl pyridine compound, which comprises the following steps of: taking hydrochloride or sulfate or nitrate of alkyl guanidine (shown in the formula II) as a reaction raw material; neutralizing with sodium hydroxide or potassium hydroxide; and then, taking toluene or xylene or chlorobenzene as a reaction solvent, and taking methanol or ethanol as a cosolvent for refluxing, dehydrating and dealcoholizing with alpha-alkyl acetoacetic ester (shown in the formula III) to react to obtain the hydroxyl pyridine compound (shown in the formula I). In the invention, by adding the methanol or ethanol as the cosolvent in the hydroxyl pyridine synthesis reaction, the solubility of the alkyl guanidine can be well increased, the decomposition of the reactants (alpha-alkyl acetoacetic ester and alkyl guanidine) is effectively controlled, the formation rate of the target product namely the hydroxyl pyridine compound shown in the general formula (I) is greatly increased, and the yield and content of the hydroxyl pyridine compound product shown in the general formula (I) are obviously improved, wherein the product yield is greater than 94%, and the product content is greater than 97%.

Description

Technical field: [0001] The invention relates to a preparation method of hydroxypyrimidine compounds. Background technique: [0002] Hydroxypyrimidines are the intermediates of very important bactericides and pesticides, and the general structural formula is as follows (formula I): [0003] [0004] Formula I: general structural formula of hydroxypyrimidine [0005] For example: the compound 2-ethylamino-5-n-butyl-6-methyl-4-hydroxy-pyrimidine (ie R 1 is CH 3 , R 2 is H, R 3 is n-C 4 h 9 , compound) is the key intermediate of the fungicide ethirimol (ethirimol) or ethirimol sulfonate (bupirimate) (GB1,182,584, GB1,400,710, J.R.Finney et al Proc.Br.Insectic.Fungic.Conf. 8th.1975,2,667); compound 2,2-dimethylamino-5-n-butyl-6-methyl-4-hydroxyl-pyrimidine (ie R 1 is CH 3 , R 2 is CH 3 , R 3 is n-C 4 h 9 , compound) is the fungicide dimethirimol (dimethirimol, GB1,182,584); compound 2,2-dimethylamino-5-methyl-6-methyl-4-hydroxy-pyrimidine (ie R 1 , R 2 , R 3 ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D239/47
Inventor 王晓光聂平毛春晖庞怀林杨彬黄兰兰陈明
Owner 湖南海利常德农药化工有限公司
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