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-3H-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-3H-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-3H-dibenz[de,h]cinnolin-3,7-dione derivatives, currently being investigated pre-clinically as anticancer agents.