the further novel antibiotics tetracycline, doxycycline, and tigecycline. Further examples of semisynthesis include the early commercial production of the anti-cancer agent paclitaxel from 10-deacetylbaccatin isolated from the needles of Taxus baccata (European yew), the preparation of LSD from ergotamine isolated from fungal cultures of ergot, and the semisynthesis of the antimalarial drug artemether from naturally-occurring artemisinin. As the field of synthetic chemistry advances, certain transformations become cheaper or easier, and the economics of a semisynthetic route may become less favorable. See also Chemurgy Drug discovery Drug development Production of cephalopsporins from 7-ACA Production of penicillins from 6-APA Production of steroids from 16-DPA References Chemical synthesis Medicinal chemistry