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Preparation method of 6-methyl-2-ethyl-3-hydroxy pyridine

A technology of hydroxypyridine and production method, applied in directions such as organic chemistry, can solve the problems of intolerant furan ring to acid, low yield, etc., and achieve the effects of shortening reaction time, controlling pollution, and green process route

Inactive Publication Date: 2012-07-25
SHAOXING UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] The acylation of 2-methylfuran requires an acid as a catalyst, but the furan ring is not acid-resistant, and the yield is 50%; the ring expansion reaction requires a polar organic solvent, and because it is an alkaline environment, a higher temperature is required for the furan ring to open, and May be substituted with pyrrole ring, so the yield is also lower (45-50%), and the pressure due to high temperature is higher

Method used

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  • Preparation method of 6-methyl-2-ethyl-3-hydroxy pyridine
  • Preparation method of 6-methyl-2-ethyl-3-hydroxy pyridine
  • Preparation method of 6-methyl-2-ethyl-3-hydroxy pyridine

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Embodiment 1

[0041] 1. Preparation of 2-propionyl-5-methylfuran:

[0042] Take 30g propionic anhydride, add 2.0g SO 4 2- / ZrO 2 , stir and heat up to 100°C, slowly add 18.8g of 2-methylfuran dropwise, during which the temperature naturally rises to 120°C, continue to keep warm at 120°C for 1h, cool to room temperature, filter to remove solid acid, and use NaOH solution to neutralize the filtrate to pH =7. The organic layer was separated and subjected to vacuum distillation to obtain light yellow liquid 26.4 with a yield of 83% (GC>98%, see attached figure 1 ).

[0043] 2. Synthesis of 6-methyl-2-ethyl-3-hydroxypyridine:

[0044] Add 80g of ammonia water, 30g of ammonium chloride, and 1g of triethylbenzylammonium resin to 20g of 2-propionyl-5-methylfuran, seal and place in an autoclave, and keep the reaction at 170°C and 3.0Mpa for 10h. Remove the catalyst by filtration, cool, add an appropriate amount of hydrazine hydrate, remove the solvent under reduced pressure, dry the filter res...

Embodiment 2

[0046] 1. Preparation of 2-propionyl-5-methylfuran:

[0047] Take 30g propionic anhydride, add 2.0g SO 4 2- / Fe 2 o 3 , stir and heat up to 100°C, slowly add 18.8g of 2-methylfuran dropwise, during which the temperature naturally rises to 120°C, continue to keep warm at 120°C for 1h, cool to room temperature, filter to remove solid acid, and use NaOH solution to neutralize the filtrate to pH =7. The organic layer was separated and distilled under reduced pressure to obtain light yellow liquid 24.5 with a yield of 77%.

[0048] 2. Synthesis of 6-methyl-2-ethyl-3-hydroxypyridine:

[0049] Add 80 g of ammonia water, 30 g of ammonium chloride, and 1 g of tributylbenzyl ammonium resin to 20 g of 2-propionyl-5-methylfuran, seal and place in an autoclave, and keep the reaction at 170°C and 3.0 Mpa for 10 hours. Remove the catalyst by filtration, cool, add an appropriate amount of hydrazine hydrate, remove the solvent under reduced pressure, dry the filter residue, and weigh it....

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Abstract

The invention discloses a preparation method of 6-methyl-2-ethyl-3-hydroxy pyridine, belonging the technical field of chemical synthesis, and comprising the following steps of adding solid acid to propionic andydride, stirring and heating, slowly dropwise adding 2-methylfuran, and reacting to obtain 2-propionyl-5-methylfuran; and then adding aqueous ammonia, ammonium chloride and resin to the 2-propionyl-5-methylfuran, and removing catalyst by filtering after reaction, removing solvent by decompressing, drawing out ammonia gas, taking out the solution for standing, separating out products, adding isopropanol for recrystallizing and filtering, filtering after filtrate is recrystallized, drying the liquor in vacuum to obtain the 6-methyl-2-ethyl-3-hydroxy pyridine. The invention can achieveexcellent yield by utilizing a solid super acidic catalyst; in addition, the invention can efficiently control the pollution, shorten the reaction time by adding a little three-phase transfer catalyst resin in the process of ring-enlargement reaction and reduce the generation of by-products.

Description

Technical field: [0001] The invention relates to a production method of 6-methyl-2-ethyl-3-hydroxypyridine (Mexidole), which belongs to the technical field of chemical synthesis. Background technique: [0002] In recent years, the morbidity and mortality of cardiovascular and cerebrovascular diseases have been increasing continuously, and they have become the first killer of human beings, seriously threatening human health. Prevention and treatment of cardiovascular and cerebrovascular diseases has become one of the most important topics in the medical field. In the past 20 years, cardiovascular and cerebrovascular system drugs have been the leading varieties in the drug market. According to recent public data, the global sales of cardiovascular and cerebrovascular drugs reached US$79 billion in 2007, estimated at an average annual growth rate of 8.5%, and is expected to exceed US$100 billion in 2010. In this field, developing a drug that is safer and more effective than ex...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/65
Inventor 沈永淼
Owner SHAOXING UNIVERSITY