Method for synthesizing 4-methyl-5-alkoxyl oxazole

A technology of alkoxy oxazole and alkoxy, which is applied in the field of organic chemical synthesis, can solve the problems that are not suitable for the development requirements of energy-saving and environmental protection industries, cannot meet the requirements of industrialized large-scale production, and have many by-products and three wastes, etc., and achieve low toxicity and low pollution , the effect of high reaction yield

Active Publication Date: 2013-03-13
DAFENG HEGNO PHARMA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The above methods all have defects such as poor reaction selectivity, low yield, and too many by-products and wastes to varying degrees, and are not suitable for the industrial development requirements of energy conservation and environmental protection and cannot meet the needs of industrialized large-scale production.

Method used

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  • Method for synthesizing 4-methyl-5-alkoxyl oxazole
  • Method for synthesizing 4-methyl-5-alkoxyl oxazole
  • Method for synthesizing 4-methyl-5-alkoxyl oxazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. Synthesis of intermediate 1-bromo-1-n-butoxyacetone

[0026] Under argon protection, at first 24.3g of acetyl bromide and 40g of 1,1-di-n-butoxyacetone prepared according to CA1153014A (the molar ratio of the two is 1:1) were heated to 60°C respectively, and then the acetyl bromide Add dropwise into 1,1-di-n-butoxyacetone, after dropping, continue to keep warm and stir for 1 hour, cool to 50°C, start vacuum distillation (11mmHg), gradually raise the temperature, collect fractions at 78-80°C, and obtain 37.7g The molar yield of intermediate 1-bromo-1-n-butoxyacetone relative to 1,1-di-n-butoxyacetone was 91.3%.

[0027] Two, synthetic target product 4-methyl-5-n-butoxy oxazole

[0028] Under the protection of argon, firstly, the obtained 37.7g intermediate 1-bromo-1-n-butoxyacetone was heated to an internal temperature of 130° C., and then 8.5 g of formamide (1-bromo-1-n-butoxyacetone was added dropwise. The molar ratio of methyl acetone and formamide is 1: 1.05); A...

Embodiment 2

[0031] Under the protection of argon, first 48.6g of acetyl bromide and 40g of 1,1-di-n-butoxyacetone (the molar ratio of the two is 2:1) were heated to 76°C respectively, and then the acetyl bromide was added dropwise to In 1,1-di-n-butoxyacetone, after dropping, continue to heat and stir for 1 hour, cool to 50°C, start vacuum (11mmHg) distillation, gradually raise the temperature, collect fractions at 78-80°C, and obtain 38.1g of intermediate 1 -Bromo-1-n-butoxyacetone, the molar yield is 92.2%.

[0032] Under the protection of argon, firstly, the obtained intermediate 1-bromo-1-n-butoxyacetone was heated to an internal temperature of 120° C., and then 8.2 g of formamide (1-bromo-1-n-butoxy The molar ratio of acetone to formamide is 1: 1); After dropping, continue to insulate and stir for 2 hours; Cool to 50°C, start vacuum (11mmHg) distillation, gradually heat up, collect 74~76°C fractions, and obtain the target product 4- Methyl-5-n-butoxyoxazole 26.0 g, GC purity 99.2%, ...

Embodiment 3

[0034] Under argon protection, first 15.5 g of acetyl chloride and 40 g of 1,1-di-n-butoxyacetone (the molar ratio of the two is 1:1) were heated to 51 ° C, and then the acetyl chloride was added dropwise to In 1,1-di-n-butoxyacetone, after dropping, continue to heat and stir for 1 hour, cool to 30°C, start vacuum (11mmHg) distillation, gradually raise the temperature, collect fractions at 52-54°C, and obtain 29.3g of intermediate 1 -Chloro-1-n-butoxyacetone, the molar yield is 90.0%.

[0035] Under the protection of argon, firstly, the obtained intermediate 1-chloro-1-n-butoxyacetone was heated to an internal temperature of 110° C., and then 8 g of formamide (1-chloro-1-n-butoxyacetone The molar ratio to formamide is 1:1); after dropping, continue to keep warm and stir for 2 hours; cool to 50°C, start vacuum (11mmHg) distillation, gradually heat up, collect fractions at 74-76°C, and obtain the target product 4-formamide 25.8 g of 1-5-n-butoxyoxazole, the GC purity was 98.8%,...

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Abstract

The invention discloses a method for synthesizing 4-methyl-5-alkoxyl oxazole, the method comprises a step b or a step a to the step b in a synthesis route, the synthesis route is shown as the follows, the step a is characterized in that 1,1-dialkoxy acetone is reacted to acetyl halides to generate 1-alcoxyl-1-halogenated acetone; the step b is characterized in that 1-alcoxyl-halogenated acetone is performed a cyclization reaction with methanamide to generate 4-methyl-5-alkoxyl oxazole; wherein the substituted group R is C2-C12 alkyl, and the substituted group X is a halogen element. The synthetic method has the advantages of simple operation, easy acquisition and small toxicity of raw material, high reaction yield and less pollution, and the industrial large production requirement can be satisfied.

Description

technical field [0001] The invention relates to a method for synthesizing 4-methyl-5-alkoxy oxazole, which belongs to the technical field of organic chemical synthesis. Background technique [0002] 4-Methyl-5-alkoxyoxazole is a useful intermediate in the preparation of vitamin B6. At present, the preparation method of 4-methyl-5-alkoxy oxazole mainly contains the following several kinds: (1) the isomerization method using alkyl isocyanate as raw material needs to be realized by heating or alkali catalysis; (2) The dehydration method with N-alkoxy oxalylalanic acid alkyl ester as raw material, such as: CN86101512; (3) with N-formylalanic acid alkyl ester as raw material, under the effect of phosphorus pentoxide, Dehydration and cyclization to obtain substituted alkoxy oxazoles, such as: Jornal of American Chemical Society, 2007, 129 (14): 4440 ~ 4445; (4) Chinese patent document CN201010618886 discloses a catalyst with amino acid ester and amine compound Below, the synthet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D263/42
Inventor 刘德铭鲁向阳闫静
Owner DAFENG HEGNO PHARMA
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