Expedient Synthesis of Lupulones and Their Derivatization to 2,8-7H-Dihydrochromen-7-ones.

A convenient and improved method for the synthesis of beta acids or lupulones, which are known to possess e. g. anti-cancer, anti-inflammatory, anti-oxidative and antimicrobial activity, has been developed successfully. Further derivatization of these complex structures to the corresponding dihydrochromen-7-ones, including the natural product machuone, was realized to simplify their analysis and to confirm their molecular structure. In addition to practical and safe laboratory procedures, the advantages associated with this new approach involve the use of water as a solvent and the direct crystallization of lupunones from acetonitrile, rendering our strategy more efficient and benign as compared to available methods.