STUDIES ON AROMATIC SESQUITERPENES .14. C ONVERSION OF 2-METHYL-6-(4-METHOXY-3-METHYLPHENYL)-2-HEPTANOL TO BICYCLIC SESQUITERPENES BY ACID CATALYTIC REACTION

o-Methylanisole was converted to 2-methyl-6-(4-methoxy-3-methylphenyl) -2-heptanol (1) via 4-(4-methoxy-3-methylphenyl)pentanoic acid (4). Th e treatment of the monocyclic tertiary alcohol (1) with p-toluenesulfo nic acid in refluxing toluene afforded a mixture of bicyclic compounds , 6-methoxyisocalamenene (11), 7-methoxycalamenene (12), methoxy-4,5-d imethyl-1,2,3,4-tetrahydronaphthalene (13), 6-methoxydaucalene (14) an d 7-methoxycadalene (15), along with a deoxy compound, 2-methyl-6-(4-m ethoxy-3-methylphenyl)heptane (16). Among the products, 11 and 14 were new compounds. In order to identify the structures of the new sesquit erpenes (11) adn (14), these compounds were synthesized by an unambigu ous route via 3, dihydro-7-methoxy-4,6-dimethyl-1(2H)-naphthalenone (1 9) prepared from 4-(4-methoxy-3-methylphenyl)pentanoic acid (4).