Abstract
Infrared spectra of structurally known pinocamphone (II), 2-methylenecyclohexanone dimere (III), 2-methylcyclohexanone (IV), and 2-ethylcyclohexanone (V) and that of aritasone were compared at νc=o, and it was concluded that the structure of aritasone, considered to be a dimer of pinocarvone, would be more appropriately represented by (Ib) than (Ia). In this case, the ring with the carbonyl in (Ib) would be in chair form and the bond of the carbonyl and ether is assumed to be in coplanar direction.
