Synthesis and evaluation of nitrogen-containing derivatives of 3,11-dioxo-olean-12-en-30-oic acid against HIV-1 protease - Liangliang Zheng; Bowen Pan; Tingting Tang; Huilin Xu; Weili Hu; Youqing Zhang; Xin Wei; Xia Liu; Qing Wu; Yang Shi; Jian Yang; Ying Zhou; et al. (Natural Product Research, 2025)