4-Toluenesulfonyl chloride → 6-(Dimethylaminomethyl)furo[3,2-c]pyridine

To a solution of triethylamine (3.45 mL, 24.7 mmol) in methylene chloride (16 mL) under a nitrogen atmosphere and cooled below 5° C. was added p-toluenesulfonyl chloride (4.65 g, 24.4 mmol) in one portion. After stirring the mixture for 15 minutes, a solution of 6-hydroxymethylfuro[3,2-c]pyridine (2.68 g, 18 mmol) in methylene chloride (18 mL) was added dropwise. By tlc the reaction was complete in 6-8 hours. Dimethylamine gas was bubbled over the reaction surface until product formation was complete. The reaction solution was washed with water and the product extracted into dilute hydrochloric acid. The acidic aqueous extract was made basic with sodium hydroxide solution and the product extracted into diethyl ether. The ethereal solution was dried over anhydrous sodium sulfate, filtered through a pad of charcoal and evaporated to give an oil (1.76 g). The oil was distilled under vacuum to give 1.56 g (49% yield) of pure product, bp: 93°-94° C./1.6 mm Hg. Upon standing the product crystallized, mp: 42°-44° C.