6,8-ditert-butyl-2-oxochromene-3-carbonitrile

6,8-ditert-butyl-2-oxochromene-3-carboxylic acid

2,4-ditert-butyl-6-(4,5-diphenyl-1,3-dihydroimidazol-2-ylidene)cyclohexa-2,4-dien-1-one

2,4-ditert-butyl-6-[(cyclohexylamino)methylidene]cyclohexa-2,4-dien-1-one