2-cyclohexyl-4,8-dimesityl-6,6-dimethyl-1-oxa-4,8-diazaspiro[2.5]octane-5,7-dione

4,8-dimesityl-6,6-dimethyl-2-(4-nitrophenyl)-1,4,8-triazaspiro[2.5]oct-1-ene-5,7-dione

4,8-dimesityl-2-(4-methoxyphenyl)-6,6-dimethyl-1,4,8-triazaspiro[2.5]oct-1-ene-5,7-dione