4-Methoxyphenylhydrazine hydrochloride → 1-[4-Methoxyphenyl]-3-trifluoromethyl-6-[4-iodophenyl]-1,4,5,6-tetrahydropyrazolo-[3,4-c]-pyridin-7-one

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Reaction Steps

1-(4-iodophenyl)-4-(trifluoroacetyl)-2,3-piperidinedione from Part C (10.0 g, 24.3 mmol) and 4-methoxyphenylhydrazine hydrochloride (4.28 g, 24.3 mmol) were dissolved in HCl (1N, 200 mL) and methanol (400 mL). The mixture was refluxed overnight. The reaction mixture was cooled to room temperature and quenched with water. It was extracted with ethyl acetate, washed with brine, and dried (Na2SO4). Purification by silica gel chromatography using 0%-100% ethyl acetate/hexane gradient as eluent afforded the desired pyrazole 9.28 g (74%). 1HNMR (CDCl3) δ 7.69 (d, 2H), 7.45 (d, 2H), 7.06 (d, 2H), 6.92 (d, 2H), 4.11 (t, 2H), 3.81 (s, 3H), 3.15 (t, 2H) ppm; Mass Spec (M+H)+514.3.

Provenance & Evidence