Sodium hydride → 1-[3-(Dimethylamino)propyl]-3-(1-methyl-4-piperidinyl)-1H-indazole difumarate

Participants

Reaction Steps

To a stirred suspension of 1.15 g of sodium hydride (50% oil dispersion) in 30 ml of dimethylformamide, under nitrogen, was added dropwise 4.3 g of 3-(1-methyl-4-piperidinyl)-1H-indazole dissolved in 30 ml of hot dimethylformamide. After stirring at ambient temperature for 1 hr, a solution of 3.3 g of dimethylaminopropylchloride in 30 ml of toluene was added dropwise. The reaction was then heated at 60° for 1 hr and then stirred at ambient temperature for 16 hrs. The reaction mixture was poured into water and the aqueous suspension was extracted with ethyl acetate (3×150 ml). The organic extracts were combined, washed with water, brine, dried over anhydrous magnesium sulfate, and the solvent evaporated in vacuo to yield an oil. The oil was dissolved in 25 ml of acetonitrile and 4.6 g of fumaric acid was added. The mixture was warmed on the steam bath (ca. 15 min), and then left at ambient temperature for 15 hrs. The resultant solid was filtered and recrystallized from dimethylformamide (thrice) with cooling (ca. 5°) to yield 1.4 g (18.7%) of product, mp 161°-163° C.

Provenance & Evidence