Abstract

Background: A one-pot method for the preparation of the corresponding alkoxy acetic acids by low-temperature ozonolysis of allyl ethers/esters followed by treatment with semicarbazide hydrochloride has been suggested. The reaction occurs via formation of acetoxyhydroperoxide, subsequent reduction of which depends on the process temperature and the nature of the starting substrate.

Objective: The article is aimed at the development of one-pot method for obtaining practically important alkoxy acetic acids, because the ozonolytic cleavage of a С=С double bond is the key step in full syntheses of many biologically active compounds.

Methods: We used a low temperature ozonolysis of functionally substituted olefins in the system acetic acid-methylene dichloride followed by reduction of semicarbazide hydrochloride. To create a method we have used available allyl ethers/esters as starting materials.

Results: We investigated reaction of the peroxide products of ozonolysis of monoallyl ethers, ester and diallyl ethers in an АсОН/CH₂Cl₂ mixture on treatment with semicarbazide hydrochloride at various temperatures. We have discovered that the selectivity of reduction of acetoxyhydroperoxide formed at the first stage depends both on the process temperature and on the nature of the starting substrate. A decrease in temperature favors acid hydrolysis and formation of a carboxylic acid.

Conclusion: We have proposed a simple and highly efficient one-pot method for the preparation alkoxy acetic acids without isolation of intermediate peroxides.

Keywords: Allyl esters, olefins, semicarbazide hydrochloride, low-temperature ozonolysis, acetoxyhydroperoxide, intermediate, alkoxy acetic acids.

Graphical Abstract