Preparation method of 5-methyl isoxazole-4-ethyl formate
A technology of methylisoxazole and ethyl formate, applied in the field of medicinal chemistry, can solve the problems of high regioselectivity, reduced product purity, low isomer content, etc. high rate effect
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
Example Embodiment
[0039] Example 1: Preparation of ethyl 2-ethoxymethylene acetoacetate (III)
[0040] Add 133.1g (1.02mol) of ethyl acetoacetate, 184.6g (1.24mol) of triethyl orthoformate, and 256.2g (2.01mol) of acetic anhydride into a 1000ml four-necked flask equipped with a rectifying column. 115-125°C, by-products with low boiling points (≤100°C) are fractionated during the reaction. After 2 hours of reaction, TLC detection (ethyl acetate: petroleum ether=1: 2 as the developing solvent) no raw materials to stop the reaction, vacuum distillation collect 106-1 10 ℃ / 0.69kPa fraction, a light yellow liquid 2-ethoxymethylene 156 g of ethyl acetoacetate, the yield was 84.7%, and the content of ethyl 2-ethoxymethylene acetoacetate was 99.10% (detected by gas chromatography).
Example Embodiment
[0041] Example 2: Preparation of ethyl 2-ethoxymethylene acetoacetate (III)
[0042] Add 260.5g (2.00mol) of ethyl acetoacetate, 362.6g (2.44mol) of triethyl orthoformate, and 521.1g (4.09mol) of ethyl acetic anhydride into a 2000ml four-necked flask equipped with a rectifying column. 113-121℃, the by-products with low boiling point (≤100℃) are also fractionated during the reaction. After 2 hours of reaction, TLC detection (ethyl acetate: petroleum ether = 1:2 as the developing solvent) no raw materials to stop the reaction, vacuum distillation to collect 106-108 ℃ / 0.67kPa fraction, a light yellow liquid 2-ethoxymethylene acetyl 309.5 g of ethyl acetate, the yield was 83.1%, and the content of ethyl 2-ethoxymethylene acetoacetate was 99.2% (detected by gas chromatography).
Example Embodiment
[0043] Example 3: Preparation of ethyl 5-methylisoxazole-4-carboxylate (IV) 2.52g (0.036mol) of hydroxylamine hydrochloride and 9ml of water were stirred and dissolved at 5°C, and sodium hydroxide was slowly added under stirring to adjust the pH of the solution To 12.1. Prepare 6.14g (0.033mol) of ethyl 2-ethoxymethylene acetoacetate and mix with 7ml of absolute ethanol solution, add dropwise the above-prepared aqueous hydroxylamine hydrochloride and sodium hydroxide solution at room temperature, and react with stirring at 25°C for 4h ( TLC followed the progress of the reaction, ethyl acetate: petroleum ether = 1:4 as the developing solvent). After the reaction was completed, the reaction solution was divided into two layers, and the upper organic phase solution was separated; the lower aqueous phase solution was extracted with dichloromethane (2×50 ml), and the organic phases were combined. The organic phase was washed with water (4×50ml) until the water layer became neutral,...
PUM
Abstract
Description
Claims
Application Information
- R&D Engineer
- R&D Manager
- IP Professional
- Industry Leading Data Capabilities
- Powerful AI technology
- Patent DNA Extraction
Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.
© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap