The chemistry of 2H‐3,1‐benzoxazine‐2,4(1H)‐dione (isatoic anhydride). 9. Synthesis of 2‐arylquinoline alkaloids

A one‐step synthesis of N ‐methyl‐2‐aryl‐4‐quinolone alkaloids is described. These compounds are readily prepared from the reaction of an N ‐methylisatoic anhydride with the lithium enolate of an acetophenone. By this method, the reaction of N ‐methylisatoic anhydride ( 5 ) or 5‐methoxy‐ N ‐methylisatoic anhydride ( 7 ) with acetophenone produces the alkaloids N ‐methyl‐2‐phenyl‐4‐quinolone ( 1 ) and eduline ( 2 ) in 81% and 70% yield, respectively. An analogous reaction of 5 with 3,4‐methylenedioxyacetophenone gives graveoline ( 3 ) in 63% yield whereas 7 and α‐methoxyacetophenone affords japonine ( 4 ) in 61% yield.