Patent ID: 6310255
Filing Date: 2001-10-30
Classification: C07C,Y02P

Abstract:
A process for producing hinokitiol which comprises the step of obtaining 1-isopropylcyclopentadiene from cyclopentadiene and an isopropylating agent represented by the general formula R--X wherein R is an isopropyl group and X is a halogen atom, a tosyl group or an alkylsulfonate group (first step), reacting the 1-isopropylcyclopentadiene with a dihaloketene to obtain a ketene adduct (second step), and decomposing the ketene adduct (third step), said first step comprising the following three steps:a) a step of preparing a cyclopentadienyl metal from cyclopentadiene and at least one of a metal hydroxide or a metal alkoxide (preparation step of cyclopentadienyl metal);b) a step of obtaining isopropylcyclopentadiene by reacting the cyclopentadienyl metal with the isopropylating agent in the presence of an aprotic polar solvent capable of forming two liquid phases when mixed with isopropylcyclopentadiene as a product (isopropylation step); andc) a step of isomerizing 5-isopropylcyclopentadiene in the isopropylcyclopentadiene selectively to 1-isopropylcyclopentadiene with heat (isomerization step).