A New Method for the Preparation of Intermediates for 2,6‐Substituted Anthrapyridazones

A new method for the preparation of 2‐substituted 6‐chloro‐2,7‐dihydro‐3 H ‐dibenzo[ de , h ]cynnoline‐3,7‐diones has been developed. The compounds have been obtained in an original three‐step procedure comprising the oxidation of 1‐methyl‐9,10‐anthraquinones with periodate or permanganate/brominating reagent systems, cyclization to 6‐chloro‐2,7‐dihydro‐3 H ‐dibenzo[ de , h ]cynnoline‐3,7‐dione, and selective alkylation thereof. The selected processes were applied in the efficient scale‐up of specific 2,6‐substituted 2,7‐dihydro‐3 H ‐dibenz[ de , h ]cinnolin‐3,7‐dione derivatives, currently being investigated pre‐clinically as anticancer agents.