ethyl 9,10-bis((tert-butylthio)methyl)-9,10-dihydro-9,10-ethanoanthracene-11-carboxylate

11-ethyl 10,9-dimethyl 9,10-dihydro-9,10-ethanoanthracene-9,10,11-tricarboxylate

11-(ethoxycarbonyl)-9,10-dihydro-9,10-ethanoanthracene-9,10-diyl diacetate

ethyl 9,10-diphenoxy-9,10-dihydro-9,10-ethanoanthracene-11-carboxylate