Water → 1-(p-chlorophenyl)-1,4-dihydro-beta,beta,1-trimethyl-3,1-benzazasiline-3(2H)-ethanol

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Reaction Steps

The crude benzazasilinium chloride (34.8 g., 92 m mol) obtained in part (a) above is dissolved in 20 ml. of water and 10 ml. of methanol and the solution is added with stirring to 52.6 g. (1.38 mol) of sodium borohydride in 500 ml. of peroxide free 1,2-dimethoxyethane between 20° and 30° C. After stirring 16 hours, the reaction mixture is poured into an ice-toluene-sodium potassium tartrate-water mixture. The organic phase is washed with water, dried with sodium sulfate and concentrated to an oil. The latter is passed in chloroform through a short silica gel column. The main portion of the effluent is concentrated to yield the title product as an oil. When dissolved in acetone and upon adding 2 g. of HCl gas with cooling and addition of ethyl ether, the free base is converted into the hydrochloride salt. The resultant crystals (m.p. 197°-198° C.) are recrystallized from ethanol-acetone-ether (ca. 1:2:5) and methanol-acetone-ether (ca. 1:3:5) and then acetone to obtain the purified salt (199°-200.5° C.).

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