Fig. 3. Key 1H–1H in Pimarane, abietane, and labdane diterpenoids from Euphorbia pekinensis Rupr. and their anti-tumor activities

Fig. 3. Key 1H–1H COSY (red bold lines) and HMBC (blue→) of compound 9 (a), NOSEY correlation (blue→) of compound 9 (b), The ORTEP drawing of compound 9 (c). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)