Synthesis of Bufalitoxin and Bufotoxin

Article abstract of DOI:10.1021/jo00392a014

Completion of a formal total synthetic route to the toad venom constituents bufotalin (8), cinobufagin (2a), bufalitoxin (3f), and bufotoxin (1a) has been accomplished.Bufalin (3a) was employed as relay and converted to 14-dehydrobufalin 3-acetate (4).Selective oxidation of olefin 4 with a chromium trioxide-pyridine reagent afforded 16-ketone 5, which we had previously transformed to bufotalin (8) and thence to cinobufagin (2a).Condensation of bufalin (3a) with suberic anhydride followed by a mixed carbonic anhydride reaction sequence using arginine monohydrochloride yielded bufalitoxin (3f), and an analogous route from bufotalin (8) led to bufotoxin (1a).