Fig. 2. Key 1 H– 1 H in Pimarane, abietane, and labdane diterpenoids from Euphorbia pekinensis Rupr. and their anti-tumor activities

Fig. 2. Key 1 H– 1 H COSY (red bold lines) and HMBC (blue→) of compounds 5 (a1) and 16 (a2), NOSEY correlation (blue→) of compounds 5 (b1) and 16 (b2), The ORTEP drawing of compounds 5 (c1) and 16 (c2). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)Published as part of Chen, Yan-Yan, Zeng, Xiao-Tao, Xu, Ding-Qiao, Yue, Shi-Jun, Fu, Rui-Jia, Yang, Xue, Liu, Zhao-Xi & Tang, Yu-Ping, 2022, Pimarane, abietane, and labdane diterpenoids from Euphorbia pekinensis Rupr. and their anti-tumor activities, pp. 1-8 in Phytochemistry (113113) 197 on page 3, DOI: 10.1016/j.phytochem.2022.113113, http://zenodo.org/record/823523