Hydrochloric Acid → 2-[4-(1,2,3,4-Tetrahydro-8-methoxy-2-naphthalenyl)-1-piperazinyl]pyrimidine

Participants

Reaction Steps

8-Methoxy-2-tetralone (3.5 g, 20 mmole), 1-(2-pyrimidinyl) piperazine dihydrochloride (4.6 g, 20 mmole), 0.38 g of p-toluenesulfonic acid and 3.48 ml of diisopropylethylamine were combined in 200 ml of toluene and the mixture refluxed under N2 for three days with water removal via a Dean-Stark trap. After the reaction had cooled, 10.5 ml of 4 N isopropanolic HCl was added, followed in portions by 5.93 g of tetra-n-butyl ammonium cyanoborohydride. The mixture was refluxed under N2 for one hour and the solvent removed in vacuum. The residue was redissolved in 300 ml of CHCl3, washed with saturated NaHCO3 solution, dried over MgSO4, filtered, and evaporated in vacuum. The crude product was column chromatographed on 75 g of silica gel employing chloroform as the eluent and the relevant fractions were combined and concentrated in vacuum. The crude title compound was crystallized from 50 ml of isopropanol with addition of 4 N isopropanolic HCl to obtain 2.0 g of the title compound as the monohydrochloride. A second crystallization from isopropanol gave 1.3 g of monohydrochloride, m.p. 273°-276° C. (d).

Provenance & Evidence