2- and 6-methyl-1,4-naphthoquinone derivatives and potential bioreductive alkylating agents.

A number of antineoplastic agents possess both the quinone nucleus and an appropriate substituent that permits them to function as bioreductive alkylating agents. To develop new compounds of this type with unique properties, we have synthesized a series of 2- and 6-methyl-1,4-naphthoquinone derivatives and have evaluated them for antineoplastic activity against Sarcoma 180 ascites cells. Several of these quinones showed antitumor activity, causing significant prolongation of the survival time of tumor-bearing mice. Among the most active agents were the mesylates, tosylates, and N-(chloroethyl)carbamates of 2- and 6-methyl-1,4-naphthoquinone. That bioreductive activation to a quinone methide might be involved in the mechanism of action of these agents was shown by the finding that compounds with the best leaving groups were the most efficacious as antineoplastic agents.