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Method for synthesizing 5-alkoxy-substituted oxazole compound

A technology for oxazoles and compounds, which is applied in the field of chemical synthesis of 5-alkoxy-substituted oxazoles, can solve problems such as the limitation of large-scale industrial application, and achieves good promotion and application prospects, mild reaction conditions, and reaction yields. high rate effect

Active Publication Date: 2013-04-17
ZHEJIANG UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the above types of substituted oxazole synthesis methods use phosphorus-containing compounds to synthesize, which are easy to produce a large amount of phosphorus-containing by-products, so large-scale industrial applications are greatly limited

Method used

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  • Method for synthesizing 5-alkoxy-substituted oxazole compound
  • Method for synthesizing 5-alkoxy-substituted oxazole compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 14

[0021] The preparation of embodiment 14-methyl-5-ethoxy-2-oxazole carboxylic acid ethyl ester

[0022] (acid-binding agent is triethylamine, and catalyzer is N, N-diethyl-p-chlorobenzamide, and substrate (I) is N-ethoxyoxalylalanine ethyl ester, and the molar ratio of feeding material is ( I): triethylamine: BTC=1: 3.8: 0.4)

[0023] Add 12g N-ethoxyoxalylalanine ethyl ester (0.055mol) and 21.1g triethylamine (0.21mol) in a 250mL three-necked reaction flask equipped with magnetic stirring, drying tube, thermometer and dropping funnel, 3.5 % equivalent catalyst (0.406g, 1.93mmol), after dissolving with 20ml dichloromethane, stir and cool down to 0-5°C under ice-water bath, then add dropwise bis(trichloromethyl)carbonate solution (6.5g, 0.022mol , dissolved in 25ml of dichloromethane), the temperature was controlled at 0-5°C, the dripping was completed in about 1 hour, and the reaction was carried out at 25-30°C for 2 hours after the ice bath was removed. Then it was directly ...

Embodiment 24

[0024] The preparation of embodiment 24-methyl-5-ethoxy-2-oxazolecarboxylic acid ethyl ester

[0025] (acid-binding agent is triethylamine, and catalyzer is N, N-diethyl-p-bromobenzamide, and substrate (I) is N-ethoxyoxalylalanine ethyl ester, and the molar ratio of feeding material is ( I): triethylamine: BTC=1: 3.3: 0.4)

[0026] 20g N-ethoxyoxalylalanine ethyl ester (0.092mol) and 29.8g triethylamine (0.30mol), 3% equivalent catalyst (0.70g, 2.75mmol), after dissolving with 25ml chlorobenzene, under ice-water bath Stir to lower the temperature to 0-5°C, then add bis(trichloromethyl)carbonate solution (11.0g, 0.037mol, dissolved in 35ml chlorobenzene) dropwise, the temperature is controlled at 0-5°C, and the dropwise is completed in about 1 hour. Remove the ice bath and react at 25-30°C for 2 hours. Then it was directly heated to 85-87° C. for 7 hours, followed by TLC (the developing solvent was petroleum ether: ethyl acetate=3:1 (v / v)). After the reaction is over, separa...

Embodiment 34

[0027]Preparation of Example 34-methyl-5-ethoxyl-2-oxazolecarboxylic acid ethyl ester

[0028] (acid-binding agent is triethylamine, and catalyzer is N, N-diethyl-p-fluorobenzamide, and substrate (I) is N-ethoxyoxalylalanine ethyl ester, and the molar ratio of feeding material is ( I): triethylamine: BTC=1: 3.8: 0.5)

[0029] 25g ethyl N-ethoxyoxalylalanine (0.115mol) and 44.1g triethylamine (0.44mol), 5% equivalent catalyst (1.12g, 5.74mmol), with 30ml 1,2-dichloroethane After dissolving, stir in an ice-water bath and cool down to 0-5°C, then add bis(trichloromethyl)carbonate solution (17.1g, 0.057mol, dissolved in 60ml 1,2-dichloroethane) dropwise, and the temperature is controlled at 0-5°C, about 1 hour to finish dripping, remove the ice bath and react at 25-30°C for 2 hours. Then it was directly heated to 80-83° C. for 7 hours, followed by TLC (the developing solvent was petroleum ether: ethyl acetate=3:1 (v / v)). After the reaction is over, separate and purify the react...

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Abstract

The invention discloses a method for synthesizing a 5-alkoxy-substituted oxazole compound, comprising the steps of dissolving an amino-acid ester derivative shown as a formula (I), an acid binding agent (R5) 3N and a catalytic agent shown as a formula (II) into an organic solvent, controlling the temperature to be between 0 DEG C and 8 DEG C and dropwise adding a bis(trichloromethyl) carbonic ester solution which is dissolved with the organic solvent, reacting at a temperature of 25-30 DEG C for 2-3 hours after the dropwise adding ends, heating to 38-93 DEG C and reacting for 6-8 hours, and separating and purifying the reaction liquid after the reaction ends to obtain the 5-alkoxy-substituted oxazole compound. The method for synthesizing the 5-alkoxy-substituted oxazole compound has the advantages of easiness of obtaining the raw materials, mild reaction conditions, convenience of operation, high yield, less pollution and the like, and is a chemical synthetic method with a better popularization and application prospect.

Description

(1) Technical field [0001] The invention relates to a chemical synthesis method of 5-alkoxy-substituted oxazole compounds. (2) Background technology [0002] 5-Alkoxy-substituted oxazoles are important intermediates in organic chemistry and pharmaceutical synthesis. Many compounds containing the parent structure of the oxazole ring have shown wide application and development prospects. For example, 4-methyl-5-alkoxy substituted oxazole is an important intermediate in the synthesis and industrial production of vitamin B6, and plays a particularly important role. [0003] There are many synthetic methods of 5-alkoxyl substituted oxazole existing reports, mainly containing the following classes: (a) P with N-formylalanine ethyl ester as raw material 2 o 5 Dehydration ring method, such as literature: GB966804; (b) thermal isomerization method using α-isocyanoalkyl ester as raw material, such as (1) CN1405158A, (2) Bull.Chem.Soc.Japan, 1971, 44 : 1407-1410; (c) Phosphorus oxy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D263/42
Inventor 苏为科李振华金灿施湘君邹晔章根宝
Owner ZHEJIANG UNIV OF TECH