An efficient synthesis of 2‐hydroxy‐6‐methylbenzob]1,6]naphthyridin‐1(2H)‐one was devised. The hydroxy group was alkylated, acylated and replaced by hydrogen. Electrophilic nitration, bromination and chlorosulfonation occurred readily in the 4‐position. From the last, various sulfonamide derivatives were prepared. A selection of the products was screened by the National Cancer Institute. Cytotoxicities were generally low.
