Unlock instant, AI-driven research and patent intelligence for your innovation.

Preparation method of α-alkoxymethylene-β-dicarbonyl compound

A technology for alkoxymethylene and dicarbonyl compounds, which is applied in the field of preparation of α-alkoxymethylene-β-dicarbonyl compounds, can solve problems such as difficulty, achieve efficient synthesis, realize industrial application, Improve the effect of low product yield

Active Publication Date: 2021-04-30
LIER CHEM CO LTD +1
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the inventors have found in practice that using acetic anhydride as a solvent will generate the acetylated impurities shown below, and this impurity is more difficult in subsequent processing, so it is necessary to avoid the generation of this impurity

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Preparation method of α-alkoxymethylene-β-dicarbonyl compound
  • Preparation method of α-alkoxymethylene-β-dicarbonyl compound
  • Preparation method of α-alkoxymethylene-β-dicarbonyl compound

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0048] Through extensive screening of reaction conditions, the preparation method of α-alkoxymethylene-β-dicarbonyl compound provided by the present invention comprises the following steps:

[0049] A, in the presence of a Lewis acid, the compound of formula I is reacted with a formylating reagent in a carboxylic acid solvent;

[0050] B, reacting the product obtained in step A with an alkylating agent to obtain α-alkoxymethylene-β-dicarbonyl compounds shown in formula II;

[0051]

[0052] Among them, R 1 is a substituted or unsubstituted benzene ring, R 2 For C1 ~ C6 alkyl or 3 ~ 6 membered cycloalkyl, R 3 It is a C1-C6 alkyl group. The substituent is a C1-C6 alkoxy group, a C1-C6 alkylthio group or a C1-C6 alkyl group substituted by a halogen.

[0053] In the present invention, when R 1 for R 2 is cyclopropane; R 3 When it is methyl or ethyl, the compound of formula II can be used to prepare isoxazole compounds, so as to realize application in the field of medic...

Embodiment 1

[0077] Embodiment one (table 1 number 1)

[0078] Add 20g (0.0662mol, 1.0eq) of compound A, 50g of acetic acid, and 19.6g (0.132mol, 2eq) of triethyl orthoformate into a 250mL three-necked flask, and heat up to 50°C for reaction. After the temperature was stabilized, the reaction was started while the vacuum distillation was carried out. The internal temperature was 50° C., and the diaphragm vacuum pump showed that the internal pressure of the reaction bottle was 50 hPa. After reacting for 8 hours, cool down to room temperature, release the vacuum, and protect it with nitrogen gas when the vacuum is released. 24.6 g of oil was obtained, and the relative content of product liquid phase 254 nm was 40.2%.

Embodiment 2

[0079] Embodiment two (table 1 number 4)

[0080] Add 20g (0.0662mol, 1.0eq) of compound A, 50g of acetic acid, 19.6g (0.132mol, 2eq) of triethyl orthoformate, 0.6g (0.00662mol, 0.1eq) of concentrated sulfuric acid into a 250mL three-necked flask, and heat up to 50°C for reaction . After the temperature was stabilized, the reaction was started while the vacuum distillation was carried out. The internal temperature was 50° C., and the diaphragm vacuum pump showed that the internal pressure of the reaction bottle was 50 hPa. After reacting for 8 hours, cool down to room temperature, release the vacuum, and protect it with nitrogen gas when the vacuum is released. 24.7 g of oil was obtained, and the relative content of product liquid phase 254 nm was 53.3%.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a method for preparing an α-alkoxymethylene-β-dicarbonyl compound, belonging to the technical field of organic synthesis. In order to solve the problem of producing impurities when using acetic anhydride as a solvent to synthesize α-alkoxymethylene-β-dicarbonyl compounds, the present invention provides a preparation of α-alkoxymethylene-β-dicarbonyl compounds Method: under Lewis acid, the compound of formula I is reacted with a formylating agent in a carboxylic acid solvent; then reacted with an alkylating agent to obtain an α-alkoxymethylene-β-dicarbonyl compound. The present invention adopts carboxylic acid solvent to avoid the problem that the raw material reacts with acetic anhydride to generate impurities when acetic anhydride is used as the solvent; at the same time, Lewis acid is added to improve the problem of low product yield caused by using carboxylic acid solvent alone, making the raw material β The conversion rate of the -dicarbonyl compound and the yield of the product α-alkoxymethylene-β-dicarbonyl compound can basically reach more than 95%.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a preparation method of an α-alkoxymethylene-β-dicarbonyl compound. Background technique [0002] α-Alkoxymethylene-β-dicarbonyl compounds are an important class of chemical intermediates that can be used to prepare isoxazole rings. In the prior art, the β-dicarbonyl compound is usually reacted in the presence of acetic anhydride solvent. [0003] CN104529924A discloses a preparation method of 5-cyclopropyl-4-[2-methylthio-4-(trifluoromethyl)benzoyl]isoxazole, and CN105712944A discloses a kind of isoxazole compound and The preparation method of its intermediates, "Study on the Synthesis of Isoxaflutole" ([D]. Shanghai: East China University of Science and Technology. 2103) introduces the synthesis mechanism of α-alkoxymethylene-β-dicarbonyl compounds , but these three documents all use acetic anhydride as solvent. [0004] However, the inventors have foun...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07C319/20C07C323/22
CPCC07C319/20C07C2601/02C07C323/22
Inventor 梁维平曾伟姚中伟左翔程柯
Owner LIER CHEM CO LTD