Isopropylamine → [6-(dimethylamino)hexyl]-4,5-diphenyl-1H-pyrazole-1-acetamide

Participants

Reaction Steps

A mixture of 8 g (0.026 mol) of ethyl 4,5-diphenyl-1H-pyrazole-1-acetate of Example 1, 4.1 g (0.028 mol) of dimethylaminohexylamine and 33.3 mL (0.19 mol) of diisopropylethylamine was stirred on a steam bath under nitrogen for 18 hours. Thin layer chromatography on silica gel with 5% isopropylamine in chloroform showed incomplete reaction. Another 1 mL of dimethylaminohexylamine was added and stirring continued on a steam bath for an additional 24 hours. The reaction was stripped in vacuo, taken up in 200 mL of ether, washed two times with water, washed once with half saturated sodium bicarbonate solution, washed with water again, washed with saturated sodium chloride solution, dried over magnesium sulfate, treated with decolorizing carbon, filtered and stripped. The residue was taken up in ether and treated with a slight excess of hydrochloric acid. The hydrochloride salt was extracted into water and washed three times with ether; the water layer was chilled, and made basic with solid sodium carbonate and extracted two times with ether. The ether extracts were combined, washed once with saturated sodium chloride, dried over magnesium sulfate, treated with decolorizing carbon, filtered and stripped. The resulting residue was triturated in pentane to yield 4.14 g of N-([6-(dimethylamino)hexyl]-4,5-diphenyl-1H-pyrazole-1-acetamide, mp 60°-63° C.

Provenance & Evidence