UNUSUAL TRANSFORMATIONS OF 2,3- AND 1,3- BUTHANEDIOL MONOPROPARGYL ETHERS

Research in the field of chemistry of oxygen-containing derivatives of acetylene has acquired considerable interest. Of the simple ethers containing a triple carbon-carbon bond, ethynyl and propargyl ethers of monohydric alcohols and phenols, as well as alkyl and aryl ethers of acetylene glycols have been studied in most detail. Alkynyl, especially propargyl mono- and diesters of polyhydric alcohols have not been studied extensively. Due to the presence of highly reactive centers, ethers occupy a special place in the field of chemistry of oxygen-containing derivatives of acetylenes. Acetylene ethers of glycols usually form ketoxy esters under conditions of acid-catalytic hydration. Using the tendency of propargyl compounds to prototropy in a basic medium, we studied under these conditions the possibility of converting monopropargyl ethers of 2,3- and 1,3-butanediols into oxygen-containing heterocycles. The available data indicate that these types of triple-bonded ethers are of great interest, both theoretically and practically. Among acetylenic ethers of polyhydric alcohols, which are the most interesting class of oxygen-containing alkynes in terms of synthesis and practice, propargyl ethers of acyclic glycols have been studied. In this regard, we have undertaken an experimental study of the synthesis routes of mono- and dipropargyl ethers of glycols and their unusual transformations. Acetylene ethers have proven themselves to be very valuable substances used in various fields of organic synthesis and exhibiting interesting properties of applied nature. Propargyl mono- and diesters of polyhydric alcohols with a triple bond are of great interest, both theoretically and practically. The paper presents the results of a study of acid-catalytic intramolecular cyclohydration and the synthesis of heterocyclic compounds based on propargyl ethers of glycols. The latter were monopropargyl ethers of 2,3- and 1,3-butanediols (I, II). The structure of the obtained heterocyclic compounds was confirmed by NMR and IR absorption spectra. Keywords: cyclohydration, monopropargyl ethers, heterocyclization, butanediols, spectrum, dioxane, t-BuO, NaOH.