Benzaldehyde → 1-(1-Hydroxy-1,2,3,4-tetrahydro-1-naphthyl)-3-dimethylamino-1-phenyl-1-propene

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Reaction Conditions

Reaction Steps

A 1.9M solution (30.4 cc) of tert-butyllithium in pentane is added to a solution of β-dimethylamino-α-methylpropiophenone 2,4,6-triisopropylbenzenesulphonylhydrazone (10.9 g) in 1,2-dimethoxyethane (109 cc), kept under nitrogen atmosphere at a temperature in the region of -75° C. Once the addition has been completed the reaction mixture is warmed slowly to 15° C. When gas evolution has stopped, the reaction mixture is cooled to a temperature in the region of -40° C. Benzaldehyde (4.2 g) is then added and stirring is continued for 20 minutes while the temperature is allowed to rise to approximately -5° C. Distilled water (50 cc), an aqueous solution (7 cc) of concentrated hydrochloric acid, and then ethyl ether (200 cc) are added in succession. The organic phase is separated and then extracted with a 4N aqueous solution of hydrochloric acid (2×25 cc). The aqueous phases are combined, made alkaline to a pH in the region of 10 with a 10N aqueous solution of sodium hydroxide and then extracted with ethyl acetate (3×150 cc). The organic phases are combined, dried over magnesium sulphate, filtered and then concentrated to dryness under reduced pressure (2.7 kPa) at 30° C. The orange oil obtained is dissolved in acetone (91 cc); a 5.6N solution (4.5 cc) of hydrochloric acid gas in ethyl ether is added to the solution obtained. The solid formed is separated off by filtration and then recrystallised from a mixture (48 cc) of isopropanol and isopropyl ether (80/20 by volume). In this way 4-dimethylamino-1,2-diphenyl-3-methyl-2-buten-1-ol (Z) hydrochloride (1.85 g) is obtained in the form of a white powder melting at 212° C.

Provenance & Evidence