Studies in sesquiterpenes-XLI:Isolongifolene (Part 2): Dehydrogenation

Dehydrogenation of isolongifolene over 10% Pd-C, in the vapour phase, at 450-±5° gave in 23% yield a mixture of naphthalenes, consisting essentially of 1-methylnaphthalene (7·5%). 1-methyl-7-isopropylnaphthalene (eudalene, 67·5%), 1-methyl-6-isopropylnaphthalene (2·8%) and 1,6-dimethyl-7-ethylnaphthalene (7·0%). The formation of these products is in complete accord with the structure I advanced earlier for isolongifolene