Sodium Hydroxide → (5-Amino-1H-pyrazol-4-yl)(thiophen-2-yl)methanone

Participants

Reaction Steps

To a mixture of aminoguanidine nitrate (17.1, 125 mmol) and α-[(dimethylamino)methylene]-β-oxo-2-thiophenepropanenitrile (3) (20.6 g, 100 mmol) in commercial absolute ethanol (120 mL) is added 10N NaOH (5 g of solid NaOH in 12.5 mL of water). The reaction mixture is refluxed for 6 hrs and the solvents removed at reduced pressure on a rotary evaporator. Water (250 mL) is added and an initial precipitate forms and is filtered (13.3 g, 68.8 mmol, 69%). On further standing the aqueous layer deposits an additional quantity of the titled compound (3.42 g, 17.7 mmol, 18%), yielding product (4) as a tan solid (total 16.72 g, 86.5 mmol, 87%).

Provenance & Evidence