N ‐ and O ‐Methyl Derivatives of 2,3,5,10‐Tetrahydrobenzo[ g ]isoquinoline‐3,5,10‐triones

Some 2,3,5,10‐tetrahydrobenzo[g]isoquinoline‐3,5,10‐triones 2 were prepared by a Diels‐Alder reaction between different 2‐azadienes 1 and 1,4‐naphthoquinone. The corresponding N ‐ and O ‐methyl derivatives 3 and 4 respectively were obtained by the use of CH 3 I in a basic medium: triethylamine (method A ), K 2 CO 3 and tris[2‐(2‐methoxyethoxy)ethylamine] (method B ) or in the presence of Ag 2 O. The reaction of N ‐methylation was regiospecific, while the O ‐methylation was regioselective. ‐ The in vitro cytotoxic activity of the prepared compounds was evaluated against murine L 1210 leukemia cells and a human tumor cell line MDA‐MB 231. A weak, not significant activity was observed (IC 50 values are ranging from 6 to > 10 μg/ml).