Trifluoroacetic acid → HCID 67257610, compound

Participants

Reaction Steps

A mixture of (3R,4R)-3-(3-Ethoxy-4-methoxy-phenyl)-N-[(1R)-1-(4-methoxy-phenyl)-ethyl]-tetrahydro-2H-thiopyran-4-amine hydrochloride (1.0 g; compound C14) and trifluoroacetic acid (2 ml) is stirred at reflux temperature for 30 min yielding a dark red solution. Cooled to RT the solution is evaporated, the dark viscous residue is dissolved in a mixture of diethylether (5 ml) and water (5 ml) and the pH of the solution is increased up to 10 by adding some drops of a 40% aqueous solution of sodium hydroxide. The mixture is extracted with diethylether, the organic phase is washed with a saturated aqueous solution of NaHCO3 and then extracted two times with a 20% aqueous solution of citric acid. The pH of the collected aqueous acid solutions of about 2.4 is increased up to 10 by adding a 40% NaOH solution and the basic mixture is extracted with diethylether. The organic phase is washed two times with water, dried over sodium sulfate and then evaporated to give an oily residue. This is dissolved in 2-propanol (10 ml) and to the stirred solution a 5-6 M solution of hydrogen chloride in 2-propanol (1 ml) is added dropwise at RT inducing a spontaneous crystallization. The slurry is concentrated to about half of the volume and stirred for 15 h at RT. The crystals are filtered off, washed with 2-propanol (2 ml), dried in vacuo at 40° C. to give the title compound. M.p. 233° C. (decomposition).

Provenance & Evidence