Hydrochloric Acid → 3-Oxo-3-(5,6,7,8-tetrahydronaphthalen-2-yl)propanenitrile

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Reaction Steps

Acetonitrile (21.48 mL, 411 mmol) was added to a stirred suspension of 60% NaH (7.05 g, 176 mmol) in dioxane (200 mL) and the resulting mixture was stirred at room temp for 20 min. Solution of ethyl 5,6,7,8-tetrahydronaphthalene-2-carboxylate (12 g, 58.7 mmol) in dioxane (50 mL) was then added and the mixture was heated at reflux for 4 h. After cooling to room temp, water followed by 1N HCl (100 mL) was added and the mixture was extracted twice with dichloromethane, dried (Na2SO4), filtered and concentrated to afford 3-oxo-3-(5,6,7,8-tetrahydronaphthalen-2-yl)propanenitrile as dark solid. A mixture of this syrup and hydrazine hydrate (2.77 mL, 88 mmol) in ethanol (200 mL) was heated at reflux for 16 h. The reaction mixture was cooled to room temp and concentrated in vacuo. The residue was diluted with dichloromethane and washed with water, dried (Na2SO4), filtered, concentrated and purified by silica gel chromatography (5-10% MeOH/CH2Cl2) to afford desired 3-(5,6,7,8-tetrahydronaphthalen-2-yl)-1H-pyrazol-5-amine (6.1 g, 28.6 mmol, 48.7% yield) as yellow solid. 1H NMR (400 MHz, CDCl3) δ 7.26 (d, J=3.5 Hz, 2H), 7.12 (d, J=7.8 Hz, 1H), 5.89 (s, 1H), 4.14 (br. s., 3H), 2.88-2.75 (m, 4H), 1.83 (dt, J=6.1, 3.4 Hz, 4H). LCMS (M+H)=214.2.

Provenance & Evidence