Microwave-mediated solventless synthesis of new derivatives of marine alkaloid Leucettamine B

New access to N-alkyl derivatives of the marine alkaloid Leucettamine B are described using two three-step convergent routes. For the formation of the 2-amino imidazolone ring, the key steps involve solvent-free condensations under microwaves and guanylation reactions with non-sterically hindered primary amines.