A Simplified Method for Synthesis of Tetrahydroiso-α-acid Standards for High-Performance Liquid Chromatography

Abstract

A simplified method for synthesis of pure tetrahydroiso-α-acid homologs for use as high-performance liquid chromatography standards was developed. The synthesis involved converting phloroglucinol to β-acids followed by hydrogenation to 4-desoxytetrahydro-α-acids, oxidation to tetrahydro-α-acids, and isomerization to tetrahydroiso-α-acids. Carbon and proton nuclear magnetic resonance spectra of the standards showed that each consisted of a single isomer. The standards were assigned the cis configuration based on a comparison of the carbon nuclear magnetic resonance spectra with those of the isohumulones.