A series of novel unsymmetrically N, N′-substituted ureas were synthesized from dehydroabietic acid and their structures were characterized by IR, 1 H-NMR, 13 C-NMR spectroscopy and single crystal X-ray diffraction. Three six-membered rings of urea 4c exhibited plane, half-chair and chair configurations, respectively. Their cytotoxicity activities against SMMC7721 liver cancer cells were evaluated by MTT (3-(4, 5-dimethylthiazol-2-yl) ...
