Mode of attack of hydriodic acid on unsaturated glyceryl ethers

Abstract

The mode of action of hydriodic acid (HI) on a sample rich in selachyl alcohol [1-O-9(cis)-octadecenyl glycerol] has been studied. HI attacked the olefinic bonds as well as the ether bonds, with the formation of at least two diiodides as well as the expected primary iodide. Subsequent conversion of these iodides to the acetates yielded a mixture of saturated diacetates and monounsaturated monoacetates. The unsaturated acetates consisted of a mixture of positional isomers and showed the presence of a trans double bond. On the basis of these results it was concluded that HI can attack on either side of the double bond, with the resultant formation of isomeric products in the subsequent dehydrohalogenation reaction.A reaction scheme for formation of these products is presented. The use of HI in studies of the structure of unsaturated glyceryl ethers is not recommended.

Keywords

• glyceryl ethers
• unsaturated ethers
• hydriodic acid attack
• gas-liquid chromatography
• long-chain iodides
• ether cleavage