Abstract The sesquiterpene β-naphthol, 7-hydroxycadalene, found inter alia in the heartwood of a number of Ulmus spp. undergoes oxidation on silica gel to mansonone C, one of several related sesquiterpene ortho-quinones produced in some Ulmus spp. in response to certain stresses. The reaction, which appears to involve oxygen adsorbed on the silica gel, proceeds under an argon atmosphere and is dramatically retarded in the ...
