A Three-Component Condensation of 2,5-Dialkyl-Phenols, Isobutyric Aldehyde, and Nitriles. Synthesis of New 2-Azaspiro[4.5]Deca-6,9-Dien-8-Ones and 2-Azaspiro[4.5]Deca-1,6,9-Trien-8-Ones

The interaction of 2,5-dialkylphenols (2,5-dimethylphenol and 2-isopropyl-5-methylphenol) with isobutyric aldehyde and nitriles in the presence of concentrated sulfuric acid as catalyst resulted in the formation of 1-R-9-alkyl-3,3,6-trimethyl-2-azaspiro[4.5]deca-6,9-dien-8-ones and 1-R-9-alkyl3,3,6-trimethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones.