Chemistry of hop constituents. Part XXXVII. Separation and characterisation of cis- and trans-isohumulone and deduction of absolute configurations
Superior conditions for the isomerisation of (–)-humulone into (+)-cis- and (–)-trans-isohumulone are described, together with a highly effective separation on Kieselgel H. The isohumulones are fully characterised for the first time, the mechanism of their formation is discussed, and their absolute configuration is deduced. That of the cis- and trans-humulinic acids follows.