抄録
1, 7-Dimethylnaphthalene was obtained by the dehydrogenation of ethyl hinokiate, C4H21COOC2H5, with selenium. The same dehydrogenation of hinokilol, C14H21CH2OH, yielded 1, 6, 7-trimethylnaphthalene. These results revealed that hinokiic acid is a tricyclic compound possessing a naphthalene nucleus substituted with two methyl groups in 1- and 7-positions and a carboxyl group in the 6-position, and another ring which is unstable to dehydrogenation. The two carbon atoms that liberated during dehydrogenation seem to have combined as a quaternary group with the nucleus, such as gem or angl type side-chain. Bicycloisohinokiic acid, C14H21COOH, the oily bicyclic product obtained on treating hinokiic acid with 50% sulfuric acid, yielded 1, 7-dimethylnaphthalene by dehydrogenation. Bicycloisohinokiic acid was found to contain a conjugated double bond which was identified by bromine absorption, catalytic hydrogenation, and addition of maleic anhydride.
