Cyclopropanation of Some Alkaloids

Abstract

New derivatives of natural compounds, galanthamine using in treatment of  Alzheimer’s disease and antitumor dimer alkaloids vinblastine and vincristine were synthesized. In the course of the reaction between galanthamine and diazomethane in the presence of a catalyst, such as palladium(II) acetate or copper(I) bromide, methylene insertion into the aromatic ring was observed instead of the expected cyclopropanation of the carbon-carbon double bond. New vindoline derivatives conjugated with amino acid esters were prepared. In Simmons-Smith reaction vinblastine and vincristine cyclopropanated in the carbon carbon double bond in position 14 and 15 of the vindoline monomer were obtained. New dimer alkaloids showed significant inhibiting effects in several tumor cell lines.