Berberine is an alkaloid derived from tyrosine. Dimethyltryptamine is an indole alkaloid derived from the shikimate pathway. Decarboxylation leads to tropane alkaloid formation. Atropine is a type of secondary metabolite called a tropane alkaloid. Quinine is an alkaloid, a naturally occurring chemical compound. Lysergamides are amide derivatives of the alkaloid lysergic acid. Coca is known throughout the world for its psychoactive alkaloid, cocaine. The first, oxymorphone, was synthesized from thebaine, an opioid alkaloid in opium poppies, in 1914. Theobromine is the primary alkaloid found in cocoa and chocolate. Baeocystin is a psilocybin mushroom alkaloid and analog of psilocybin. Norbaeocystin is a psilocybin mushroom alkaloid and analog of psilocybin. It is classified as a xanthine alkaloid, others of which include theophylline and caffeine. Strassman has also conducted similar research using psilocybin, a psychedelic alkaloid found in hallucinogenic mushrooms. The biosynthesis of the tropane alkaloid, however, is still uncertain. Vinblastine is a "vinca" alkaloid and a chemical analogue of vincristine.