NAPHTHALENE DERIVATIVE, PRODUCTION AND SYNTHETIC INTERMEDIATE THEREOF

NEW MATERIAL:A naphthalene derivative expressed by formula I or salt of said compound [R is H or alkoxycarbonyl; R is alkoxycarbonyl; one of R and R is H or alkoxy and th other is alkoxy; A is benzene ring (allowed of substitution by alkyl, etc.), benzene ring substituted by alkylene dioxy, with a proviso that in a case of R and R are simultaneously methoxycarbonyl, A is formula II or R is H, R is ethoxycarbonyl and A is formula III, one of R and R is H or >=2C alkoxy]. EXAMPLE:1-(3,4-dimethoxyphenyl)-2,3-bis(methoxycarbonyl)-4-hydro-xynap htalene. USE:Medicine having anti-lipemia action. PREPARATION:An acetylene compound expressed by formula IV is reacted with novel aldehyde compound expressed by formula V, lower alkyl acetal of said compound or salt of said compound to obtain the aimed compound expressed by formula I.