Total Synthesis of Endangered Frog Alkaloid ‘Epibatidine’, A Potent Analgesic of the Future

Abstract

’Epibatidine’ is a nicotinic alkaloid’, was first discovered in the skin of neotropical poisonous frog, ’Epipedobates tricolor’ found in Ecuador. John Daly in 1974 first isolated a trace quantity of this alkaloid by scarifying several frogs. With the evolution of NMR techniques the structure of this alkaloid was reported in 1992. An year after, Nobel Laureate Prof. E.J. Corey, devised first total synthesis for this alkaloid. Since then this molecule is constantly attracting the attention of Epibatidine is an agonist at nicotinic acetylcholine receptor. Pharmacologically it is 200 to 300 times stronger than morphine and do not cause any addition. The frog species ’Epipedobates tricolor’ is now been declared as endangered and therefore there is special need for easy syntheses to get the alkaloid for biological evaluations and to save these frogs from extinction. We have developed a Wittig Claisen based protocol for the total synthesis of this drug molecule which would help in investigation rest pharmacological activities of this drug. Structure of Epibatidine Molecule and the frog species from which it was isolated.