Ethylene → 6,8-Dichloro-2-tetralone

Participants

Reaction Steps

149.4 g of 2,4-dichlorophenylacetyl chloride dissolved in 200 ml of methylene chloride were added dropwise within 60 minutes to 115 g of aluminum chloride in 700 ml of methylene chloride while stirring at 0° to 5°. Thereafter, ethylene was introduced at between 0° and 5° during 30 minutes, whereupon the mixture was stirred further at room temperature for 1 hour and thereafter treated at between 0° and 5° with 300 ml of ice-water. The methylene chloride phase was washed, respectively, with 2N hydrochloric acid, with water, with saturated sodium bicarbonate solution and again with water. The aqueous phases were extracted with methylene chloride. The methylene chloride phases were combined, dried and evaporated. The residue was triturated with 100 ml of low-boiling petroleum ether, a further 250 ml of low-boiling petroleum ether were later added thereto and the mixture was left to stand in a refrigerator for 72 hours. The solid was filtered off and filtered over 600 g of silica gel (particle size 0.2-0.5 mm) while eluting with chloroform. There was obtained 6,8-dichloro-3,4-dihydro-2(1H)-naphthalenone which exhibits a melting point of 90°-92° after recrystallization from low-boiling petroleum ether at 0° to 5°.

Provenance & Evidence