The synthesis of glycyrrhetinic acid derivatives containing a nitrogen heterocycle and their antiproliferative effects in human leukemia cells.

Fifteen novel glycyrrhetinic acid derivatives containing a nitrogen heterocycle at C-30 and with different A-ring substituents were designed and synthesized. All of these derivatives have improved antiproliferative effects against human HL-60 leukemia cells. Compounds with a cyano-enone functionality on the A-ring exhibit greater growth inhibitory effects, compared to those with a 2-hydroxymethylene-3-keto, an isoxazole, or a 2-cyano-3-keto group. N-(2-cyano-3,11-dioxoolean-1,12-dien-30-yl)-4-piperidyl piperidine (9b) was found to be two-fold more potent than methyl 2-cyano-3,11-dioxooleana-1,12- dien-30-oate (CDODO-Me-11).