GB917864A - Tetrahydro naphthalene derivatives and a method for their preparation - Google Patents

Abstract

The invention comprises 1,2,3,4-tetrahydro-4-oxo-2-naphthalene derivatives of the formula <FORM:0917864/IV (b)/1> wherein X represents a hydrogen or halogen atom or a hydroxy p group, R1 represents a halogen atom and R represents a hydrogen atom or an alkyl group containing up to 6 carbon atoms; and a process for their preparation by ring closing a 3-benzyl glutaric acid of the formula <FORM:0917864/IV (b)/2> or the anhydride or diacyl halide thereof, with an acidic reagent to form a product in which X is either a halogen atom or a hydroxy group, and if desired, converting a product in which X is a hydroxy group into one in which X is a halogen atom by treatment with an agent such as oxalyl chloride, phosphorous pentachloride or pentabromide or thionyl chloride or bromide, and further if desired, converting a product in which X is a halogen atom into one in which X is a hydrogen atom by catalytic reduction or alkyl lithium aluminium hydride reduction. The ring closure is preferably effected in the presence of polyphosphoric or sulphuric acid. Examples describe the preparation of 8-chloro-1,2,3,4-tetrahydro-5-hydroxy- and methoxy-4-oxo-2-naphthalene-acetic acid, acetyl chloride and acetaldehyde. b -(2-chloro-5-methoxy-benzyl) - glutaric acid is prepared by converting 2-chloro-5-methoxy-toluene to 2-chloro-5-methoxy benzyl bromide by treatment with N-brom-succinimide, reacting with diethyl malonate to give diethyl 2-chloro-5-methoxy-benzyl malonate, reducing with lithium aluminium hydride to give 2-(21-chloro - 51 - methoxy benzyl) - 1,3-propanediol, esterifying with methane sulphonyl chloride to give the bis-methane sulphonate, reacting with potassium cyanide and hydrolysing.ALSO:An orange-coloured dye is obtained by reacting 1,2,3,4-tetrahydro- 4-oxo-2-naphthalene-acetyl chloride with 1,4-diamino anthraquinone.