Propargyl bromide → HCID 23468867, compound

Participants

Reaction Steps

4.15 g (0.030 mol) of anhydrous potassium carbonate are added to a solution of 2.29 g (0.010 mol) of 4-(2,3-dimethyl-5-benzofuranyl)-piperidine (c.f. Example 1) in 25 ml of acetone, and a solution of 1.3 g (0.011 mol) of 2-propynyl bromide in 11 ml of acetone is added dropwise in the course of 10 minutes, with stirring. The reaction mixture is heated to 40° for 4 hours and then cooled to room temperature and the inorganic salts are filtered off. The filtrate is evaporated in a rotary evaporator. The brown oil which remains has, in the thin layer chromatogram (silica gel/5% methanol/chloroform), a main spot at an Rf value of about 0.7, in addition to 4 secondary spots. The resulting oil is chromatographed on 50 g of silica gel using chloroform as the solvent and eluting agent, whereupon 1-(2-propynyl)-4-(2,3-dimethyl-5-benzofuranyl)-piperidine is obtained, as the main fraction, as a yellowish oil with an Rf value of about 0.7. This base is dissolved in about 3 ml of methanol and converted into the hydrochloride by acidifcation with hydrogen chloride solution and the hydrochloride is made to crystallise by adding about 20 ml of ether and is filtered off with suction. The hydrochloride thus obtained as white crystals melts at 224°-225°.

Provenance & Evidence