Studies of chromenes. Part 10. Oxiranes of nitrochromenes

Abstract

Syntheses of stable oxiranes of 5- and 7-nitro-, and 5,7-dinitro- 2,2-dimethyl(chromenes and of 7–2H-ethoxycarbonylamino)-2,2-dimethyl-5-nitro-2H-chromene are described. Thermal cyclisation of the precursor phenyl prop-2-ynyl ethers proceeds in good yield but in the case of the dinitrophenyl ether the products are highly solvent dependent. The compounds are of interest as possible antitumour alkylating agents that are activated by bioreduction to extremely reactive oxiranes.